(19)

(11)

EP 0 485 537 A1

(12)

(43) Date of publication: 20.05.1992 Bulletin 1992/21 (21) Application number: 91906882.0 (22) Date of filing: 29.03.1991

(51) International Patent Classification (IPC):  C30B 19/ 04( . ) H01L 21/ 208( . ) H01L 21/ 20( . ) (86) International application number: PCT/RO1991/000001 (87) International publication number: WO 1991/015361 (17.10.1991 Gazette 1991/24)

(84) Designated Contracting States: AT BE CH DE DK ES FR GB GR IT LI LU NL SE (30) Priority: 30.03.1990 RO 19330001446 (71) Applicant: INSTITUTUL DE FIZICA ATOMICA R-7000 Bucuresti (RO)	(72) Inventors: PETRESCU-PRAHOVA, Iulian, Basarab Sect. 6 R-7000 Bucuresti (RO) LEPSA, Mihail, Ion Sect. 5 R-7000 Bucuresti (RO) (74) Representative: Brereton, Paul Arthur  REDDIE & GROSE 16 Theobalds Road London WC1X 8PL London WC1X 8PL (GB)