(19)
(11)EP 3 208 855 B1

(12)EUROPEAN PATENT SPECIFICATION

(45)Mention of the grant of the patent:
26.06.2019 Bulletin 2019/26

(21)Application number: 16156120.4

(22)Date of filing:  17.02.2016
(51)International Patent Classification (IPC): 
H01L 45/00(2006.01)

(54)

RESISTIVE SWITCHING MEMORY CELL

WIDERSTANDSSCHALTENDE SPEICHERZELLE

CELLULE DE MÉMOIRE À COMMUTATION RÉSISTIVE


(84)Designated Contracting States:
AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

(43)Date of publication of application:
23.08.2017 Bulletin 2017/34

(73)Proprietor: Heraeus Deutschland GmbH & Co. KG
63450 Hanau (DE)

(72)Inventor:
  • NEUMANN, Christian
    35410 Hungen (DE)

(74)Representative: Maiwald Patent- und Rechtsanwaltsgesellschaft mbH 
Elisenhof Elisenstraße 3
80335 München
80335 München (DE)


(56)References cited: : 
GB-A- 1 386 098
US-A1- 2009 200 535
US-A1- 2006 109 708
US-B1- 9 246 091
  
  • SCHINDLER C ET AL: "Bipolar and Unipolar Resistive Switching in Cu-Doped SiO2", IEEE TRANSACTIONS ON ELECTRON DEVICES, vol. 54, no. 10, October 2007 (2007-10), pages 2762-2768, XP011193103, ISSN: 0018-9383, DOI: 10.1109/TED.2007.904402
  • HSIEH W-K ET AL: "Asymmetric resistive switching characteristics of In2O3:SiO2 cosputtered thin film memories", JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B, vol. 32, no. 2, 3 February 2014 (2014-02-03), XP012181480, ISSN: 2166-2746, DOI: 10.1116/1.4863915 [retrieved on 1901-01-01]
  
Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention).


Description

FIELD OF THE INVENTION



[0001] The present invention relates to a resistive switching memory cell, a process for the manufacture of a resistive switching memory cell and a memory device comprising the resistive memory switching cell.

BACKGROUND OF THE INVENTION



[0002] Non-volatile memory devices are used in a multitude of everyday electronics, e.g. smartphones, music players, USB-sticks, memory cards, e.g. for digital cameras, solid-state disks (SSDs) etc.

[0003] Non-volatile memories such as the so-called EPROM-technology has certain limits as regards the storage density, access, erase and writing times making it undesirable for the constantly increasing data volume in modern applications, such as the ones mentioned above.

[0004] A further technology for non-volatile memories are resistive switching memories which are formed of arrays of resistive switching elements. Each of these elements has two or more stable resistive states. Switching between the states is accomplished by specific voltage pulses.

[0005] Resistive switching elements use a "forming process" to prepare a memory device for use. The forming process is typically applied at the factory, at assembly, or at initial system configuration. A resistive switching material is normally insulating, but a sufficient voltage (known as a forming voltage) applied to the resistive switching material will form a conductive pathway in the resistive switching material. Through the appropriate application of various voltages (e.g. a set voltage and reset voltage), the conductive pathways may be modified to form a high resistance state or a low resistance state. For example, a resistive switching material may change from a first resistivity to a second resistivity upon the application of a set voltage, and from the second resistivity back to the first resistivity upon the application of a reset voltage which voltages are usually different from each other.

[0006] Two types of ReRAM switching elements are currently under investigation, namely valence change memory (VCM) and electrochemical metallisation memory (ECM). In VCMs oxygen anions are removed from a metal oxide matrix whereupon the conductivity of the metal oxide matrix increases. In ECMs metal ions are reduced and build filaments within the matrix between the two electrodes thereby increasing the electrical conductivity. It has recently been found (cf. http://www.fz-juelich.de/SharedDocs/Pressemitteilungen/UK/DE/2015/15-09-28nnano_reram.html) that in VCMs in addition to the oxygen ion movement also filaments are formed. However, in VCMs elemental oxygen needs to be stored which may migrate to the surface of the electrode and cause delamination thereof.

[0007] US 2009/200535 A1 discloses an ECM cell with a GeS matrix comprising 1-5% of In, Sn or Sb to increase the amount of mobile Ag and the temperature stability of the device. A similar ECM cell is disclosed by US 2006/109708 A1, wherein a few percent of A1 or Cu are added to stabilise a GeSe matrix.

[0008] GB 1 386 098 describes a bistable resistance switch/memory based on a 6:1:6 lead-alumino-silicate glass electrolyte with Cu ions.

[0009] C Schindler et al (IEEE Transactions on Electron Devices, vol. 54, no. 10, October 2007, pages 2762-2768) teaches a Cu ion ECM cell with SiO2 matrix, and W-K Hsieh et al (Journal of Vacuum Science & Technology B, vol. 32, no. 2, February 2014, 020601) investigates a VCM cell with In2O3 doped SiO2 matrix.

[0010] In current solid states electrolytes usually amorphous metal oxides are used as matrix whereby the transport of a metal ion therethrough leads to built-up and dissolution of a metallic filament between the two electrodes attached thereto. After a multitude of switching processes the structure of the solid state electrolyte changes leading to separate metallic phases of the ion to be transported and, in turn continuously changes the switching behaviour of the electrolyte making the switch unusable as memory. Moreover, a high degree of purity is desired in order to suppress side reactions and phase separations.

[0011] Thus, a resistive switching memory cell is needed which is not prone to changes in the switching behaviour or which at least has a significant lower rate of change thereof due to the charge-state stabilization of the mobile ion in the matrix.

[0012] It has been found that this can be achieved by introducing a fixed local charge compensation element into the crystalline or amorphous matrix which has a lower valence state that the metal ion of the matrix.

[0013] Hence, the present invention provides a resistive switching memory cell comprising a switchable solid electrolyte (E) according to the independent claim 1, the electrolyte (E) consisting of a composition comprising
  • a matrix comprising a metal oxide as matrix material, the metal oxide comprising at least two metals M1 and M2;
  • a metal M3 which is mobile in the matrix;
    wherein
    • the atomic ratio of M1 to M2 is within the range of 75:25 to 99.99:0.01, preferably 90:10 to 99.99:0.01;
    • the valence states of M1, M2 and M3 are all positive;
    • the valence state of M1 is larger than the valence state of M2;
    • the valence state of M2 is equal to or larger than the valence state of M3; and
    • the metals M1, M2 and M3 are different.


[0014] It has been found that the above switching element has a significantly improved switching behaviour. It is the current understanding that the negative localized charges caused by the metal M2 in the matrix improves the ion hopping conductivity by simply enlarging the number of accessible hopping centers. Moreover, the solubility of the metal M3 is also believed to be improved such that the build-up of localized phases, e.g. consisting of secondary metallic nanoparticles, is avoided or at least significantly reduced. Thus, the valence state of the metal M3 seems to be stabilized. Hence, undesired change of the switching behaviour, especially changes of the set and reset voltages after a certain number of switching cycles is significantly reduced and, thus, the lifetime of the device is improved. Moreover, the variation of the resistance of the respective resistance state around their respective maxima is lower (i.e. their Gaussian distribution is narrower) possibly enabling to use three or more states within the same memory cell. Even in case only two states are used these states are more clearly distinguished from each other. Moreover, the variation of the set and re-set voltages, respectively, of different cells having the same assembly is lower.

[0015] The resistive switching memory cell of the present invention is preferably a resistive switching memory cell based on electrochemical metallisation (ECM).

[0016] In the present invention the term "metal" generally denotes the elements of the periodic table except hydrogen, the noble gases, the halogenides, B, C, N, O, P, S, Se and Te.

Composition the switchable solid electrolyte (E) is consisting of



[0017] The valence states of M1, M2 and M3 are all positive. Thus, in the composition according to the present invention the metal are present in cationic form.

[0018] The metals M1, M2 and M3 are different. In the present invention this denotes that M1, M2 and M3 are each based on a different element of the periodic table.

[0019] As outlined above, the matrix is comprising a metal oxide comprising at least two metals M1 and M2, and the atomic ratio of M1 to M2 is within the range of 75:25 to 99.99:0.01, preferably 90:10 to 99.99:0.01.

[0020] The matrix is a metal oxide of the metal M1, wherein the metal M2 partially substitutes the metal M1. Due to the lower valence state of M2 compared with M1 localized negative charges results. This negative localized charge is believed to improve the mobility of the metal M3 and stabilizes its oxidation state.

[0021] The metal M3 is mobile in the matrix. Usually, the ratio of the diffusion coefficient of M3 in the composition to the diffusion coefficient of M2 in the composition is at least 1000:1, preferably at least 10,000:1, more preferably at least 100,000:1 and most preferably 1,000,000:1. The method for determining the diffusion coefficient is described in the experimental part. Usually the ratio of the diffusion coefficients will not exceed 108:1.

[0022] Preferably the diffusion coefficient of the metal M2 at 1100°C is 1·10-10 cm2/s or below, more preferably 1·10-10 cm2/s or below and most preferably 1·10-12 cm2/s or below.

[0023] Preferably the diffusion coefficient of the metal M3 at 1100°C is 1·10-7 cm2/s or higher, more preferably 5·10-6 cm2/s or higher and most preferably 1 ·10-5 cm2/s or higher.

[0024] The method for determining the diffusion coefficient is described in detail in the experimental part.

[0025] The composition is preferably essentially free of alkaline metals and alkaline-earth metals. In the present invention "essentially free of alkaline metals and alkaline-earth metals" denotes that the total concentration of alkaline metals and alkaline-earth metals is below 100 ppm, based on the total weight of the composition.

[0026] According to the present invention, the total concentration of metals different from M1, M2 and M3 is below 100 ppm, based on the total weight of the composition.

[0027] As outlined above, the valence state of M2 is equal to or larger than the valence state of M3, preferably, the valence state of M2 is larger than the valence state of M3.

[0028] According to the present invention, the valence state of M1 is +III or +IV, preferably +IV. The valence state of M2 is lower than the valence state of M1. Preferably the valence state of M2 is +I to +III, more preferably +II or +III and most preferably +III. Preferably the valence state of M3 is +I to +III, more preferably +I or +II.

[0029] In one embodiment, the valence state of M1 is +IV, the valence state of M2 is +II or +III and the valence state of M3 is +I or +II.

[0030] In yet another, preferred embodiment the valence state of M1 is +IV, the valence state of M2 is +III and the valence state of M3 is +I or +II.

[0031] According to the present invention, M1 is selected from Si and Ge, more preferably M1 is Si.

[0032] According to the present invention, M2 is selected from the group consisting of Al, Ga, In, Tl, Sc, Y, La, Ac or mixtures thereof, preferably Al, Ga, In, and most preferably is selected from Al and/or Ga.

[0033] As outlined above, the metal M2 may also be a mixture of two or more metals, although M2 being a single metal is preferred.

[0034] According to the present invention, M3 is selected from the group consisting of Ag and Cu, and is most preferably Cu.

[0035] The atomic ratio of M1 to M2 is within the range of 75:25 to 99.99:0.01, preferably 90:10 to 99.99:0.01, more preferably within the range of 95.0:5.0 to 99.9:0.10, even more preferably within the range of 96.0:4.0 to 99.0:1.0.

[0036] Preferably,
  • the amount of M2 is 0.01 to 25 atom% based on the entirety of metals present in the composition; and/or
  • the amount of M3 is 0.01 to 10 atom% based on the entirety of metals present in the composition;
    more preferably,
  • the amount of M2 is 0.1 to 10.0 atom% based on the entirety of metals present in the composition; and/or
  • the amount of M3 is 0.1 to 8.0 atom% based on the entirety of metals present in the composition;
    even more preferably,
  • the amount of M2 is 1.0 to 5.0 atom% based on the entirety of metals present in the composition; and/or
  • the amount of M3 is 1.0 to 4.0 atom% based on the entirety of metals present in the composition.


[0037] Preferably,
  • the amount of M2 is 0.01 to 25 atom% based on the entirety of metals present in the composition; and
  • the amount of M3 is 0.01 to 10 atom% based on the entirety of metals present in the composition;
    more preferably,
  • the amount of M2 is 0.1 to 10.0 atom% based on the entirety of metals present in the composition; and
  • the amount of M3 is 0.1 to 8.0 atom% based on the entirety of metals present in the composition;
    even more preferably,
  • the amount of M2 is 1.0 to 5.0 atom% based on the entirety of metals present in the composition; and
  • the amount of M3 is 1.0 to 4.0 atom% based on the entirety of metals present in the composition;


[0038] In a preferred variant of the present invention the composition comprises
  1. (i) a matrix comprising a metal oxide as matrix, the matrix comprising two metals M1 and M2, M1 being Si;
  2. (ii) a metal M3 which is mobile in the matrix
wherein
  • the atomic ratio of M1 to M2 is within the range of 75:25 to 99.99:0.01, preferably 90:10 to 99.99:0.01;
  • the valence states of M1, M2 and M3 are all positive;
  • the valence state of M1 is +IV;
  • the valence state of M2 is +III or below;
  • the valence state of M2 is equal to or larger than the valence state of M3; and
  • the metals M1, M2 and M3 are different.


[0039] In the following preferred features of this variant are described.

[0040] In this variant the matrix is formed of amorphous or crystalline silicon dioxide, preferably amorphous silicon dioxide with the metal M2 partially replacing the silicon atoms.

[0041] The metal M3 is mobile in the matrix. Usually, the ratio of the diffusion coefficient of M3 to the diffusion coefficient of M2 is at least 1000:1, preferably at least 10,000:1, more preferably at least 100,000:1 and most preferably 1,000,000:1. The method for determining the diffusion coefficient is described in the experimental part. Usually the ratio of the diffusion coefficients will not exceed 108:1.

[0042] Preferably the diffusion coefficient of the metal M2 at 1100°C is 1·10-10 cm2/s or below, more preferably 1·10-10 cm2/s or below and most preferably 1·10-12 cm2/s or below.

[0043] Preferably the diffusion coefficient of the metal M3 at 1100°C is 1·10-7 cm2/s or higher, more preferably 5·10-6 cm2/s or higher and most preferably 1 ·10-5 cm2/s or higher.

[0044] The method for determining the diffusion coefficient is described in detail in the experimental part.

[0045] The composition is preferably essentially free of alkaline metals and alkaline-earth metals. In the present invention "essentially free of alkaline metals and alkaline-earth metals" denotes that the total concentration of alkaline metals and alkaline-earth metals is below 100 ppm, based on the total weight of the composition.

[0046] The total concentration of metals different from M1, M2 and M3 is below 100 ppm, based on the total weight of the composition.

[0047] As outlined above, the valence state of M2 is equal to or larger than the valence state of M3, preferably, the valence state of M2 is larger than the valence state of M3.

[0048] Preferably the valence state of M2 is +I to +III, more preferably +II or +III and most preferably +III.

[0049] Preferably the valence state of M3 is +I to +III, more preferably +I or +II.

[0050] Preferably the valence state of M2 is +III and the valence state of M3 is +I or +II.

[0051] M2 is selected from the group consisting of Al, Ga, In, Tl, Sc, Y, La or Ac, preferably Al, Ga, In, and most preferably is selected from Al and/or Ga.

[0052] M3 is selected from the group consisting of Ag and Cu, and is most preferably Cu.

[0053] In one embodiment of this variant, M2 is selected from the group consisting of Al, Ga, In, and M3 is Cu.

[0054] The atomic ratio of M1 to M2 is within the range of 75:25 to 99.99:0.01, more preferably 90:10 to 99.99:0.01, preferably within the range of 95.0:5.0 to 99.9:0.10, more preferably within the range of 96.0:4.0 and 99.0:1.0.

[0055] Preferably,
  • the amount of M2 is 0.01 to 25 atom% based on the entirety of metals present in the composition; and/or
  • the amount of M3 is 0.01 to 10 atom% based on the entirety of metals present in the composition;
    more preferably,
  • the amount of M2 is 0.1 to 10.0 atom% based on the entirety of metals present in the composition; and/or
  • the amount of M3 is 0.1 to 8.0 atom% based on the entirety of metals present in the composition;
    even more preferably,
  • the amount of M2 is 1.0 to 5.0 atom% based on the entirety of metals present in the composition; and/or
  • the amount of M3 is 1.0 to 4.0 atom% based on the entirety of metals present in the composition.


[0056] Preferably,
  • the amount of M2 is 0.01 to 25 atom% based on the entirety of metals present in the composition; and
  • the amount of M3 is 0.01 to 10 atom% based on the entirety of metals present in the composition;
    more preferably,
  • the amount of M2 is 0.1 to 10.0 atom% based on the entirety of metals present in the composition; and
  • the amount of M3 is 0.1 to 8.0 atom% based on the entirety of metals present in the composition;
    and most preferably,
  • the amount of M2 is 1.0 to 5.0 atom% based on the entirety of metals present in the composition; and
  • the amount of M3 is 1.0 to 4.0 atom% based on the entirety of metals present in the composition.


[0057] In the following preferred features of all embodiments of the invention are described unless explicitly stated to the contrary.

[0058] In one embodiment
  • M1 is selected from Si and Ge, more preferably M1 is Si;
  • M2 is selected from the group consisting of Al, Ga, In, TI, Sc, Y, La, Ac or mixtures thereof, preferably Al, Ga, In, and most preferably is selected from Al and/or Ga; and
  • M3 is selected from the group consisting of Ag and Cu, and is most preferably Cu.


[0059] In another embodiment
  • M1 is Si;
  • M2 is selected from the group consisting of Al, Ga, In, and most preferably is selected from Al and/or Ga; and
  • M3 is selected from the group consisting of Ag and Cu, and most preferably is Cu.


[0060] In yet another embodiment
  • M1 is Si;
  • M2 is Al; and
  • M3 is Cu.


[0061] In one further variant
  • M1 is selected from Si and Ge, more preferably M1 is Si;
  • M2 is selected from the group consisting of Al, Ga, In, Tl, Sc, Y, La, Ac or mixtures thereof, preferably Al, Ga, In, and most preferably is selected from Al and/or Ga; and
  • M3 is selected from the group consisting of Ag and Cu, and is most preferably Cu; the total concentration of metals different from M1, M2 and M3 is below 100 ppm, based on the total weight of the composition, and
  • the amount of M2 is 0.01 to 25 atom% based on the entirety of metals present in the composition; and/or
  • the amount of M3 is 0.01 to 10 atom% based on the entirety of metals present in the composition;
    more preferably,
  • the amount of M2 is 0.1 to 10.0 atom% based on the entirety of metals present in the composition; and/or
  • the amount of M3 is 0.1 to 8.0 atom% based on the entirety of metals present in the composition;
    even more preferably,
  • the amount of M2 is 1.0 to 5.0 atom% based on the entirety of metals present in the composition; and/or
  • the amount of M3 is 1.0 to 4.0 atom% based on the entirety of metals present in the composition.


[0062] In another variant
  • M1 is Si;
  • M2 is selected from the group consisting of Al, Ga, In, and most preferably is selected from Al and/or Ga; and
  • M3 is selected from the group consisting of Ag and Cu, and is most preferably Cu, the total concentration of metals different from M1, M2 and M3 is below 100 ppm, based on the total weight of the composition, and
  • the amount of M2 is 0.01 to 25 atom% based on the entirety of metals present in the composition; and
  • the amount of M3 is 0.01 to 10 atom% based on the entirety of metals present in the composition;
    more preferably,
  • the amount of M2 is 0.1 to 10.0 atom% based on the entirety of metals present in the composition; and
  • the amount of M3 is 0.1 to 8.0 atom% based on the entirety of metals present in the composition;
    even more preferably,
  • the amount of M2 is 1.0 to 5.0 atom% based on the entirety of metals present in the composition; and
  • the amount of M3 is 1.0 to 4.0 atom% based on the entirety of metals present in the composition.


[0063] In yet another variant
  • M1 is Si;
  • M2 is Al; and
  • M3 is Cu; the total concentration of metals different from M1, M2 and M3 is below 100 ppm, based on the total weight of the composition
    and
  • the amount of M2 is 0.1 to 10.0 atom% based on the entirety of metals present in the composition; and
  • the amount of M3 is 0.1 to 8.0 atom% based on the entirety of metals present in the composition;
    preferably,
  • the amount of M2 is 1.0 to 5.0 atom% based on the entirety of metals present in the composition; and
  • the amount of M3 is 1.0 to 4.0 atom% based on the entirety of metals present in the composition.


[0064] The switchable solid electrolyte as defined in the present invention can be applied in a normal resistive switching memory cell.

[0065] Such a resistive switching memory cell usually comprises
  1. (i.) a substrate;
  2. (ii.) a first electrode applied onto the substrate;
  3. (iii.) the switchable solid electrolyte (E) according to the present invention applied onto the first electrode;
  4. (iv.) optionally a layer selected from the chalcogenides of Ag, Cu, e.g. sulphides, selenides and tellurides, especially selenides and tellurides, more preferably chalcogenides of Cu, e.g. sulphide, selenide and telluride, especially telluride;
  5. (v.) a second electrode applied onto the switchable solid electrolyte (E) or the optional layer selected from the chalcogenides of Ag, Cu, e.g. sulphides, selenides and tellurides, if present.


[0066] Suitable materials for the substrate and the first and second electrode are known in the art.

[0067] Suitable substrates are known in the art.

[0068] Usually the substrate is featuring CMOS logic for addressing specific cells for read and/or write operations.

[0069] Furthermore, usually the second electrode is connected to an interconnector as known in the art.

[0070] After depositing a dielectric layer on the interconnector applied onto the second electrode a three-dimensional structure can be obtained by applying layers (ii) to (v) onto the dielectric layer. This may be repeated several times.

[0071] Preferred substrates are selected from silicon-based 1T1R CMOS logic circuitry or 1TnR crossbar logic for improved storage density optionally comprising so-called selectors as, for example, described in S.H. Jo, et al., Cross-Point Resistive RAM Based on Field-Assisted Superlinear Threshold Selector, IEEE Transactions on electron devices, Vol. 62, no 11, November 2015, p. 3477-3481.

[0072] An example for an 1T1R assembly is given in figure 4. In case of a cross-bar assembly the CMOS-logic is replaced by an interconnector and the CMOS-logic is applied to address the interconnector lines and rows of the assembly.

[0073] Preferably the materials of the first electrode and the second electrode are different.

[0074] Preferably the material of the first electrode is selected from Pt, W, Mo, TiN, more preferably W or TiN and most preferably TiN. Optionally a plug may be applied between the substrate, optionally comprising the CMOS-logic and the first electrode. The plug can be made from W.

[0075] Preferably the material of the second electrode is selected from Ag and/or Cu, and most preferably is Cu. Optionally a plug may be applied onto the second electrode or between the second electrode and the interconnector, if present. The plug can be made from W.

[0076] More preferably, the material of the first electrode is selected from Pt, W, Mo, TiN and the material of the second electrode is selected from Ag and Cu, even more preferably the material of the first electrode is selected from W or TiN and the material of the second electrode is selected from Ag and/or Cu, and most preferably the material of the first electrode is TiN and the material of the second electrode is Cu.

[0077] In one embodiment the metal of the second electrode and the metal M3 are identical.

[0078] The present invention is furthermore directed to a process for the production of the resistive switching memory cell according to the present invention. Such processes are generally known in the art. Suitable processes are, for example atomic layer deposition (ALD), chemical vapour deposition (CVD) and physical vapour deposition (PVD), for example sputtering.

[0079] Preferably, the process according to the present invention is comprising the following steps
  1. a) providing a substrate;
  2. b) applying a first electrode on the substrate;
  3. c) applying the switchable solid electrolyte (E) as defined in the present invention on the first electrode;
  4. d) optionally, applying a layer selected from the chalcogenides of Ag, Cu, e.g. sulphides, selenides and tellurides, especially selenides and tellurides, more preferably chalcogenides of Cu, e.g. sulphide, selenide and telluride, especially telluride;
  5. e) applying a second electrode onto the switchable solid electrolyte (E) obtained in step c) or the optional layer selected from the chalcogenides of Ag, Cu, e.g. sulphides, selenides and tellurides, obtained in step d), if present.


[0080] Suitable substrates are known in the art.

[0081] Usually the substrate is featuring CMOS logic for addressing specific cells for read and/or write operations.

[0082] Usually, after applying the second electrode an interconnector is applied onto the second electrode.

[0083] After depositing a dielectric layer on the interconnector applied onto the second electrode a three-dimensional structure can be obtained by repeating steps b) to e). This may be repeated several times.

[0084] Preferred substrates are selected from silicon-based 1T1R CMOS logic circuitry or 1TnR crossbar logic for improved storage density optionally comprising so-called selectors as, for example, described in S.H. Jo, et al., Cross-Point Resistive RAM Based on Field-Assisted Superlinear Threshold Selector, IEEE Transactions on electron devices, Vol. 62, no 11, November 2015, p. 3477-3481.

[0085] An example for an 1T1R assembly is given in figure 4. In case of a cross-bar assembly the CMOS-logic is replaced by an interconnector and the CMOS-logic is applied to address the interconnector lines and rows of the assembly.

[0086] As already outlined above, methods for applying the individual parts are generally known in the art, e.g. atomic layer deposition (ALD), chemical vapour deposition (CVD) and physical vapour deposition (PVD), for example sputtering.

[0087] The application of the switchable solid electrolyte (E) in step c) is preferably carried out by atomic layer deposition (ALD), chemical vapour deposition (CVD) or physical vapour deposition (PVD), for example sputtering.

[0088] In case the switchable solid electrolyte (E) is deposited layer by layer, e.g. by atomic layer deposition, the applied layers may comprise only one of the metals M1, M2 or M3 or the applied layers may comprise a mixture of two or more of M1, M2 and M3.

[0089] Applying layers only comprising one of the metals M1, M2 or M3 is usually preferred. Thereby side reactions between the precursors of the metals M1, M2 and M3 cannot take place. Moreover, in a mixture of two or more metal precursors the precursor of one of the metals may better physio- and chemisorb with the surface than the precursor of the other metal and, thus, the layer composition, i.e. content of the individual metals in the final layer may not be identical to the content in the reactant mixture.

[0090] In case layers only comprising one of the metals M1, M2 or M3 are applied subsequently the desired concentration in the final switchable solid electrolyte (E) can be easily achieved by selecting the number of the respective layers appropriately. In either case usually an annealing step is performed after all layers of the switchable solid electrolyte (E) are applied in step c) thereby forming the switchable solid electrolyte (E) according to the invention. It is also possible to apply some of the layers of the switchable solid electrolyte (E) perform an annealing step and apply further layer(s) of the switchable solid electrolyte (E) perform another annealing step until all layers of the switchable solid electrolyte (E) are applied. However, applying all layers and perform a single annealing step thereafter is preferred.

[0091] The annealing step, if present is usually performed at a temperature lower than the transition temperature of the oxide of M1, such as 50°C to 400°C.

[0092] In this regard the "transition temperature" denotes the temperature at which a material changes from one state to another, usually from a solid state to a viscous state, e.g. liquid state, or vice versa. Preferably the material is heated to the glass transition temperature or melting temperature of the oxide of M1.

[0093] The thickness of the layer is usually 1 to 100 nm, preferably 5 to 10 nm.

[0094] Preferred features of the composition and the switchable solid electrolyte (E) of the present invention are also preferred features of the process of the present invention and vice versa.

[0095] The present invention is furthermore directed to a memory device comprising the resistive switching memory cell according to the present invention or the resistive switching memory cell prepared according to the process according to the present invention. The resistive switching memory cell is preferably an electrochemical metallisation memory (ECM).

[0096] Such a memory device may be a solid state disk, a memory card, a USB-stick, a RAM-module, a memory module integrated into an electronic device, e.g. internal memory of a smartphone, digital camera, etc.

[0097] Preferred features of the composition and the process of the present invention are also preferred features of the use according to the present invention and vice versa.

[0098] The invention will now be described with the following non-limiting examples.

Experimental part


Measurement methods


Diffusion coefficient of M2 and M3



[0099] The method is performed analogous to the method described by Günther H. Frischat, in Sodium Diffusion in SiO2 Glass, Journal of The American Ceramic Society, Vol 51, No. 9, 1968, p. 528-530.

[0100] The sample was prepared by applying the solution of a radioactive tracer of the metal to be determined onto a polished glass specimen (size 10 mm · 10 mm) of Heraeus Infrasil 302® and a second glass specimen of Heraeus Infrasil 302® was applied on top thereof, thereby obtaining a sandwiched structure. Thereafter the specimen was heated to 1100°C in an oven for an appropriate time. The further procedure was as described in the above paper of Frischat items (2) and (3).

[0101] Suitable tracers are known in the art, e.g. 65Cu or 26Al.

Transition temperature, glass transition temperature, melting temperature



[0102] Determination of glass transition temperature Tg (glass)

[0103] The glass transition temperature Tg for glasses is determined using a DSC apparatus Netzsch STA 449 F3 Jupiter (Netzsch) equipped with a sample holder HTP 40000A69.010, thermocouple Type S and a platinum oven Pt S TC:S (all from Netzsch). For the measurements and data evaluation the measurement software Netzsch Messung V5.2.1 and Proteus Thermal Analysis V5.2.1 are applied. As pan for reference and sample, aluminum oxide pan GB 399972 and cap GB 399973 (both from Netzsch) with a diameter of 6.8 mm and a volume of about 85 µl are used. An amount of about 20-30 mg of the sample is weighted into the sample pan with an accuracy of 0.01 mg. The empty reference pan and the sample pan are placed in the apparatus, the oven is closed and the measurement started. A heating rate of 10 K/min is employed from a starting temperature of 25°C to an end temperature of 1000°C. The balance in the instrument is always purged with nitrogen (N2 5.0 nitrogen gas with quality 5.0 which represents a purity of 99,999%) and the oven is purged with synthetic air (80% N2 and 20% O2 from Linde) with a flow rate of 50 ml/min. The first step in the DSC signal is evaluated as glass transition using the software described above and the determined onset value is taken as the temperature for Tg.

[0104] The melting temperature Tm is determined in an analogous manner whereby the maximum in the DSC-signal is evaluated as the melting temperature Tm.

Metal content (of M1, M2, M3, alkaline and alkaline earth metals etc.)



[0105] The determination was carried out using a Varian Vista MPX ICP-OES instrument (available from Varian Inc). The system was calibrated using two reference solutions with known metal content in a 3:1 mixture of hydrofluoric acid (40 wt.%) and nitric acid (60 wt.%).

[0106] The settings of the Varian Vista MPX ICP-OES instrument were as follows.
Power settings: 1.25 kW
plasma: 15.0 l/min (Argon)
auxiliary gas: 1,50 l/min (Argon)
atomizer pressure: 220 kPa (Argon)
repetitions: 20 s
equilibration time: 45 s
observation height: 10 mm
suction time: 45 s
purging time: 10 s
pumping speed: 20 rpm
repetitions: 3


[0107] 0.10 ± 0.02 g of the sample are combined with 3 ml nitric acid and 9 ml hydrofluoric acid and heated in an Anton Paar Multiwave 3000 microwave oven at 800 to 1200 W for 60 minutes. The sample is introduced into a 100 ml volumetric flask using hydrochloric acid (50 Vol.%) and used for the measurement.

XRD measurement



[0108] In an air conditioned room with a temperature of 22 ± 1 °C equipment and materials are equilibrated prior the measurement. Crystallinity measurements were performed using a "STOE Stadi P" from STOE & Cie GmbH, Darmstadt, Germany, equipped with a CuKα1 (0.154056 nm) x-ray source, a curved Ge single crystal (111) monochromator, with transmission equipment (detector: linear PSD (position sensitive detector) from STOE), a generator "Seifert ISO-DEBYEFLEX 3003" from GE Sensing and inspection Technologies GmbH (40 kV, 40 mA) and the software "STOE Powder Diffraction Software (win x-pow) Version 3.05" from STOE. This device is applying the x-ray scattering measuring principle. Calibration of the device is in accordance to the NIST-standard Si (lot number: 640 c). As reference for the analysis the ICDD database is applied. The sample is placed in a quantity in order to achieve a thin film between two foils (comes with the sample holder from STOE) in the middle of the sample holder prior to placing it in the x-ray beam. The sample was measured in a transmission mode at 22 °C with following parameters: 2θ : 3.0-99.8 °, ω: 1.5-49.9 °, step: 2θ 0.55 °, ω: 0.275 °, step time: 20 s, measure time: 1.03 h. When plotting 2θ versus intensity using the equipped software package, the presence of peaks representing crystalline material can be detected.

Particles size determination using laser scattering



[0109] For particle size determination of the particles a laser diffraction method was used according to ISO Standard 13320. A Mastersizer 3000 from Malvern equipped with a He-Ne Laser and a blue LED and wet dispersing unit has been employed for the measurements performed at room temperature of 23°C. The conditions of the wet dispersion unit were set to 80% ultrasonic power before measurement and as a dispersant water was used. The values for d10, d50, d90 were determined using the Malvern software 21 CFR, a form factor of 1 and the Fraunhofer theory.

Porosity and pore size by Hg porosimetry



[0110] Mercury porosimetry analysis was performed according to ISO15901-1 (2005). A ThermoFisher Scientific PASCAL 140 (low pressure up to 4bar) und a PASCAL 440 (high pressure up to 4000bar) and SOLID Version 1.3.3 (08.02.2012) software (all from ThermoFisher Scientific) were calibrated with porous glass spheres with a pore diameter of 75 nm (University of Leipzig, Fakultät für Chemie und Mineralogie, Institut für Technische Chemie). During measurements the pressure was increased or decrease continuously and controlled automatically by the instrument running in the PASCAL mode and speed set to 6 for intrusion and 8 for extrusion. The Washburn method was employed for the evaluation and the density of Hg was corrected for the actual temperature. Value for surface tension was 0.484 N/m and contact angle 141.1°. Sample size was between about 30 and 40 mg. before starting a measurement samples were heated to 120°C for 24 hours. Evacuation is performed automatically by the instrument for 10 minutes to an absolute pressure of 0.01 kPa.
Used materials 
Amorphous SiO2 pyrogenic silica is slurried in deionised water and dried in a drying tower at a temperature of > 100°C thereby obtaining porous silica having a particle size (d50) of about 100 - 500 µm with an inner pore volume of about 0.7 ml/g
Al precursor anhydrous AlCl3 obtained from Alfa Aesar
Cu precursor anhydrous CuSO4 obtained from Alfa Aesar
The compositions have been prepared by infiltration of mixed solution into inner porosity of porous silica particles as follows. The properties are shown in table 1 below.

Comparative Example 1 (CE1)



[0111] 0.133 g CuSO4 are added to a round-bottomed flask and dissolved in deionized water. To this solution 500 g of the porous SiO2 as defined above are added and shaken until the mixture shows Newtonian behaviour. Subsequently the mixture is dried at 130°C on a rotary evaporator until a dry powder is obtained. The powder is transferred to an aluminium bowl and dried for 48h in a drying oven at 150 °C. Thereafter the residual humidity is determined and the sample cooled to room temperature (25°C).

[0112] Thereafter the resulting product was heated to 1700°C under a vacuum of 5 mbar for melting.

Comparative Example 2 (CE2)



[0113] Comparative example 1 has been repeated whereby 1.33 g CuSO4 have been used.

Comparative Example 3 (CE3)



[0114] Comparative example 1 has been repeated whereby 13.3 g CuSO4 have been used.

Inventive example 4 (IE4)



[0115] The procedure of comparative example 1 has been repeated whereby 0.133 g CuSO4 is added to a round-bottomed flask and dissolved in deionized water. 0.166 g AlCl3 are carefully added. To this solution 500 g of the porous SiO2 as defined above are added and the procedure of comparative example 1 has been repeated. The properties are shown in table 1 below.

Inventive example 5 (IE5)



[0116] Inventive example 4 has been repeated whereby 1.33 g CuSO4 and 1.66 g AlCl3 as prepared above have been used.

Inventive example 6 (IE6)



[0117] Inventive example 4 has been repeated whereby 13.3 g CuSO4 and 16.6 g AlCl3 as prepared above have been used.
Table 1
 appearanceCu [ppm]1)Al [ppm] 1)
CE1 slightly red, no inhomogeneity visible 135 82)
CE2 individual, separated areas of high Cu-concentration visible under the microscope 1270 12)
CE3 individual, separated areas of high Cu-concentration visible under the microscope 10102 0
IE4 no individual areas as in case of CE2 and CE3 visible 169 148
IE5 no individual areas as in case of CE2 and CE3 visible 1213 1485
IE6 no individual areas as in case of CE2 and CE3 visible 11014 14067
1) determined in powder form
2) The minimal Al-content results from impurities due to handling

XRD measurment



[0118] Figure 1 shows the XRD-curve of sample 3 and figure 2 the XRD curve of sample 6. As can be seen from the curves intensities of the peaks at about 43.5 2Theta, 50.5 2Theta and 74.0 2Theta of inventive sample 6 are significantly lower. These peaks indicate the presence of crystalline metallic copper phases having a size of 100 to 250 nm. Thus, inventive sample 6 has nearly no such phases albeit the copper content is higher compared with comparative example 3.

[0119] Sample 6 has been used as sputtering target. Onto a silicon substrate a platin electrode layer has been applied by sputtering.

[0120] Thereafter a layer of composition 6 as outlined above was applied by radio frequency sputtering at a frequency of 13.56 Mhz, at a power of 150 W (without reflection) at a pressure of 0.002 mbar with the pressure being maintained using 9 sccm (standard cubic centimeters per minute) argon and 1 sccm oxygen. The obtained sample was cleaved and an SEM image has been recorded. The result is shown in figure 3. As can be seen from Figure 3 the platinum forms a homogeneous and amorphous layer (bright area above the coarse substrate). Likewise the Cu and Al-containing composition (dark area on top of the bright area) also forms a homogenous layer not containing any intermetallic phases or the like.


Claims

1. A resistive switching memory cell comprising a switchable solid electrolyte (E), the electrolyte (E) consisting of a composition comprising

- a matrix comprising a metal oxide as matrix material, the metal oxide comprising at least two metals M1 and M2;

- a metal M3 which is mobile in the matrix; wherein

- the atomic ratio of M1 to M2 is within the range of 75:25 to 99.99:0.01, preferably 90:10 to 99.99:0.01;

- the valence states of M1, M2 and M3 are all positive;

- the valence state of M1 is larger than the valence state of M2;

- the valence state of M2 is equal to or larger than the valence state of M3; and

- the metals M1, M2 and M3 are different;
wherein

- M1 is selected from Si and Ge;

- M2 is selected from the group consisting of Al, Ga, In, Tl, Sc, Y, La, Ac or mixtures thereof;

- M3 is selected from the group consisting of Ag and Cu; and

- the total concentration of metals different from M1, M2 and M3 in the composition is below 100 ppm, based on the total weight of the composition.


 
2. The resistive switching memory cell according to claim 1, wherein the ratio of the diffusion coefficient of M3 in the composition to the diffusion coefficient of M2 in the composition is at least 1000:1.
 
3. The resistive switching memory cell according to any one of the preceding claims, wherein the resistive switching memory cell is a resistive switching memory cell based on electrochemical metallisation (ECM).
 
4. The resistive switching memory cell according to any one of the preceding claims, wherein in the composition the total concentration of alkaline metals and alkaline-earth metals is below 100 ppm, based on the total weight of the composition.
 
5. The resistive switching memory cell according to any one of the preceding claims, wherein M1 is Si.
 
6. The resistive switching memory cell according to any one of the preceding claims, wherein M2 is selected from Al, Ga, In, and most preferably is selected from Al and/or Ga.
 
7. The resistive switching memory cell according to any one of the preceding claims, wherein M3 is Cu.
 
8. The resistive switching memory cell according to any one of the preceding claims, wherein

- the amount of M2 is 0.01 to 25 atom% based on the entirety of metals present in the composition; and/or

- the amount of M3 is 0.01 to 10 atom% based on the entirety of metals present in the composition.


 
9. The resistive switching memory cell according to any one of the preceding claims, wherein the resistive switching memory cell comprises

(i.) a substrate;

(ii.) a first electrode applied onto the substrate;

(iii.) the switchable solid electrolyte (E) applied onto the first electrode;

(iv.) optionally a layer selected from the chalcogenides of Ag, Cu, e.g. sulphides, selenides and tellurides, especially selenides and tellurides, more preferably chalcogenides of Cu, e.g. sulphide, selenide and telluride, especially telluride;

(v.) a second electrode applied onto the switchable solid electrolyte (E) or the optional layer selected from the chalcogenides of Ag, Cu, e.g. sulphides, selenides and tellurides, if present.


 
10. The resistive switching memory cell according to claim 9, wherein

- the substrate is featuring CMOS logic for addressing specific cells for read and/or write operations; and/or

- the material of the first electrode is selected from Pt, Mo, W and TiN; and/or

- the material of the second electrode is selected from Ag and Cu; and/or

- the second electrode is connected to an interconnector.


 
11. A process for the production of the resistive switching memory cell according to one of the claims 1 to 10 comprising the following steps

a) providing a substrate;

b) applying a first electrode on the substrate;

c) applying the switchable solid electrolyte (E) as defined in any one of the preceding claims 1 to 8 on the first electrode;

d) optionally, applying a layer selected from the chalcogenides of Ag, Cu, e.g. sulphides, selenides and tellurides, especially selenides and tellurides, more preferably chalcogenides of Cu, e.g. sulphide, selenide and telluride, especially telluride;

e) applying a second electrode onto the switchable solid electrolyte (E) obtained in step c) or the optional layer selected from the chalcogenides of Ag, Cu, e.g. sulphides, selenides and tellurides, obtained in step d), if present.


 
12. A memory device comprising the resistive switching memory cell according to any one of the preceding claims 1 to 10 or the resistive switching memory cell prepared according to the process of claim 11.
 


Ansprüche

1. Widerstandsschaltelement-Speicherzelle, umfassend einen schaltbaren festen Elektrolyten (E), wobei der Elektrolyt (E) aus einer Zusammensetzung besteht, die umfasst:

- eine Matrix, die ein Metalloxid als Matrixmaterial umfasst, wobei das Metalloxid wenigstens zwei Metalle M1 und M2 umfasst;

- ein Metall M3, das in der Matrix mobil ist; wobei

- das Atomverhältnis von M1 zu M2 in dem Bereich von 75:25 bis 99,99:0,01, vorzugsweise 90:10 bis 99,99:0,01, liegt;

- die Valenzzustände von M1, M2 und M3 alle positiv sind;

- der Valenzzustand von M1 größer als der Valenzzustand von M2 ist;

- der Valenzzustand von M2 gleich dem oder größer als der Valenzzustand von M3 ist;
und

- die Metalle M1, M2 und M3 verschieden sind; wobei

- M1 ausgewählt ist aus Si und Ge;

- M2 ausgewählt ist aus der Gruppe bestehend aus Al, Ga, In, Tl, Sc, Y, La, Ac und Gemischen davon;

- M3 ausgewählt ist aus der Gruppe bestehend aus Ag und Cu; und

- die Gesamtkonzentration von Metallen, die von M1, M2 und M3 verschieden sind, in der Zusammensetzung kleiner als 100 ppm, bezogen auf das Gesamtgewicht der Zusammensetzung, ist.


 
2. Widerstandsschaltelement-Speicherzelle gemäß Anspruch 1, wobei das Verhältnis des Diffusionskoeffizienten von M3 in der Zusammensetzung zu dem Diffusionskoeffizienten von M2 in der Zusammensetzung wenigstens 1000:1 beträgt.
 
3. Widerstandsschaltelement-Speicherzelle gemäß einem der vorstehenden Ansprüche, wobei die Widerstandsschaltelement-Speicherzelle eine Widerstandsschaltelement-Speicherzelle auf der Grundlage elektrochemischer Metallisierung (ECM) ist.
 
4. Widerstandsschaltelement-Speicherzelle gemäß einem der vorstehenden Ansprüche, wobei in der Zusammensetzung die Gesamtkonzentration von Alkalimetallen und Erdalkalimetallen kleiner als 100 ppm, bezogen auf das Gesamtgewicht der Zusammensetzung, ist.
 
5. Widerstandsschaltelement-Speicherzelle gemäß einem der vorstehenden Ansprüche, wobei M1 Si ist.
 
6. Widerstandsschaltelement-Speicherzelle gemäß einem der vorstehenden Ansprüche, wobei M2 ausgewählt ist aus Al, Ga, In, und höchst bevorzugt ausgewählt ist aus Al und/oder Ga.
 
7. Widerstandsschaltelement-Speicherzelle gemäß einem der vorstehenden Ansprüche, wobei M3 Cu ist.
 
8. Widerstandsschaltelement-Speicherzelle gemäß einem der vorstehenden Ansprüche, wobei

- die Menge von M2 0,01 bis 25 Atom-%, bezogen auf die Gesamtmenge von in der Zusammensetzung vorhandenen Metallen, beträgt; und/oder

- die Menge von M3 0,01 bis 10 Atom-%, bezogen auf die Gesamtmenge von in der Zusammensetzung vorhandenen Metallen, beträgt.


 
9. Widerstandsschaltelement-Speicherzelle gemäß einem der vorstehenden Ansprüche, wobei die Widerstandsschaltelement-Speicherzelle umfasst:

(i.) ein Substrat;

(ii.) eine erste Elektrode, die auf das Substrat aufgebracht ist;

(iii.) den schaltbaren festen Elektrolyten (E), der auf die erste Elektrode aufgebracht ist;

(iv.) gegebenenfalls eine Schicht ausgewählt aus den Chalcogeniden von Ag, Cu, z. B. Sulfiden, Seleniden und Telluriden, insbesondere Seleniden und Telluriden, bevorzugter Chalcogeniden von Cu, z. B. Sulfid, Selenid und Tellurid, insbesondere Tellurid;

(v.) eine zweite Elektrode, die auf den schaltbaren festen Elektrolyten (E) oder die optionale Schicht ausgewählt aus den Chalcogeniden von Ag, Cu, z. B. Sulfiden, Seleniden und Telluriden, falls vorhanden, aufgebracht ist.


 
10. Widerstandsschaltelement-Speicherzelle gemäß Anspruch 9, wobei

- das Substrat CMOS-Logik zum Ansprechen spezifischer Zellen für Lese- und/oder Schreibvorgänge aufweist; und/oder

- das Material der ersten Elektrode ausgewählt ist aus Pt, Mo, W und TiN;
und/oder

- das Material der zweiten Elektrode ausgewählt ist aus Ag und Cu;
und/oder

- die zweite Elektrode mit einem Verbindungselement verbunden ist.


 
11. Verfahren zur Herstellung der Widerstandsschaltelement-Speicherzelle gemäß einem der Ansprüche 1 bis 10, umfassend folgende Schritte:

a) Bereitstellen eines Substrats;

b) Aufbringen einer ersten Elektrode auf das Substrat;

c) Aufbringen des schaltbaren festen Elektrolyten (E) gemäß einem der vorstehenden Ansprüche 1 bis 8 auf die erste Elektrode;

d) gegebenenfalls Aufbringen einer Schicht ausgewählt aus den Chalcogeniden von Ag, Cu, z. B. Sulfiden, Seleniden und Telluriden, insbesondere Seleniden und Telluriden, bevorzugter Chalcogeniden von Cu, z. B. Sulfid, Selenid und Tellurid, insbesondere Tellurid;

e) Aufbringen einer zweiten Elektrode auf den bei Schritt c) erhaltenen schaltbaren festen Elektrolyten (E) oder die bei Schritt d) erhaltene optionale Schicht ausgewählt aus den Chalcogeniden von Ag, Cu, z. B. Sulfiden, Seleniden und Telluriden, falls vorhanden.


 
12. Speichervorrichtung, umfassend die Widerstandsschaltelement-Speicherzelle gemäß einem der vorstehenden Ansprüche 1 bis 10 oder die gemäß dem Verfahren von Anspruch 11 hergestellte Widerstandsschaltelement-Speicherzelle.
 


Revendications

1. Cellule de mémoire à commutation de résistance comprenant un électrolyte solide commutable (E), l'électrolyte (E) étant constitué d'une composition comprenant

- une matrice comprenant un oxyde métallique en tant que matériau de matrice, l'oxyde métallique comprenant au moins deux métaux M1 et M2 ;

- un métal M3 qui est mobile dans la matrice ;
dans laquelle

- le rapport atomique de M1 à M2 est dans la plage de 75:25 à 99,99:0,01, de préférence de 90:10 à 99,99:0,01 ;

- les états de valence de M1, M2 et M3 sont tous positifs ;

- l'état de valence de M1 est supérieur à l'état de valence de M2 ;

- l'état de valence de M2 est supérieur ou égal à l'état de valence de M3 ; et

- les métaux M1, M2 et M3 sont différents ;
dans laquelle

- M1 est choisi entre Si et Ge ;

- M2 est choisi dans le groupe constitué par Al, Ga, In, Tl, Sc, Y, La, Ac ou les mélanges de ceux-ci ;

- M3 est choisi dans le groupe constitué par Ag et Cu ; et

- la concentration totale de métaux différents de M1, M2 et M3 dans la composition est au-dessous de 100 ppm, par rapport au poids total de la composition.


 
2. Cellule de mémoire à commutation de résistance selon la revendication 1, dans laquelle le rapport du coefficient de diffusion de M3 dans la composition au coefficient de diffusion de M2 dans la composition est d'au moins 1000:1.
 
3. Cellule de mémoire à commutation de résistance selon l'une quelconque des revendications précédentes, la cellule de mémoire à commutation de résistance étant une cellule de mémoire à commutation de résistance basée sur la métallisation électrochimique (ECM).
 
4. Cellule de mémoire à commutation de résistance selon l'une quelconque des revendications précédentes, dans laquelle dans la composition la concentration totale de métaux alcalins et de métaux alcalinoterreux est au-dessous de 100 ppm, par rapport au poids total de la composition.
 
5. Cellule de mémoire à commutation de résistance selon l'une quelconque des revendications précédentes, dans laquelle M1 est Si.
 
6. Cellule de mémoire à commutation de résistance selon l'une quelconque des revendications précédentes, dans laquelle M2 est choisi entre Al, Ga et In et le plus préférablement il est choisi entre Al et/ou Ga.
 
7. Cellule de mémoire à commutation de résistance selon l'une quelconque des revendications précédentes, dans laquelle M3 est Cu.
 
8. Cellule de mémoire à commutation de résistance selon l'une quelconque des revendications précédentes, dans laquelle

- la quantité de M2 est de 0,01 à 25 % at. par rapport à la totalité des métaux présents dans la composition ; et/ou

- la quantité de M3 est de 0,01 à 10 % at. par rapport à la totalité des métaux présents dans la composition.


 
9. Cellule de mémoire à commutation de résistance selon l'une quelconque des revendications précédentes, la cellule de mémoire à commutation de résistance comprenant

(i.) un substrat ;

(ii.) une première électrode appliquée sur le substrat ;

(iii.) l'électrolyte solide commutable (E) appliqué sur la première électrode ;

(iv.) éventuellement une couche choisie parmi les chalcogénures, par exemple les sulfures, les séléniures et les tellurures, en particulier les séléniures et les tellurures, d'Ag ou de Cu, plus préférablement les chalcogénures, par exemple le sulfure, le séléniure et le tellurure, en particulier le tellurure, de Cu ;

(v.) une seconde électrode appliquée sur l'électrolyte solide commutable (E) ou la couche facultative choisie parmi les chalcogénures, par exemple les sulfures, les séléniures et les tellurures, d'Ag ou de Cu, si elle est présente.


 
10. Cellule de mémoire à commutation de résistance selon la revendication 9, dans laquelle

- le substrat présente une logique CMOS pour l'adressage de cellules particulières pour des opérations de lecture et/ou d'écriture ; et/ou

- le matériau de la première électrode est choisi entre Pt, Mo, W et TiN ; et/ou

- le matériau de la seconde électrode est choisi entre Ag et Cu ; et/ou

- la seconde électrode est connectée à un interconnecteur.


 
11. Procédé pour la production de la cellule de mémoire à commutation de résistance selon l'une des revendications 1 à 10 comprenant les étapes suivantes

a) l'utilisation d'un substrat ;

b) l'application d'une première électrode sur le substrat ;

c) l'application de l'électrolyte solide commutable (E) tel que défini dans l'une quelconque des revendications 1 à 8 précédentes sur la première électrode ;

d) éventuellement, l'application d'une couche choisie parmi les chalcogénures, par exemple les sulfures, les séléniures et les tellurures, en particulier les séléniures et les tellurures, d'Ag ou de Cu, plus préférablement les chalcogénures, par exemple le sulfure, le séléniure et le tellurure, en particulier le tellurure, de Cu ;

e) l'application d'une seconde électrode sur l'électrolyte solide commutable (E) obtenu dans l'étape c) ou sur la couche facultative choisie parmi les chalcogénures, par exemple les sulfures, les séléniures et les tellurures, d'Ag ou de Cu, obtenue dans l'étape d), si elle est présente.


 
12. Dispositif de mémoire comprenant la cellule de mémoire à commutation de résistance selon l'une quelconque des revendications 1 à 10 précédentes ou la cellule de mémoire à commutation de résistance préparée selon le procédé de la revendication 11.
 




Drawing

















Cited references

REFERENCES CITED IN THE DESCRIPTION



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Patent documents cited in the description




Non-patent literature cited in the description