(19)

(11)

EP 1 019 970 A1

(12)

(43) Date of publication: 19.07.2000 Bulletin 2000/29 (21) Application number: 98944118.3 (22) Date of filing: 25.09.1998

(51) International Patent Classification (IPC)7: H01L 33/00, H01L 25/13, A61C 19/00 (86) International application number: PCT/GB9802/905 (87) International publication number: WO 9916/136 (01.04.1999 Gazette 1999/13)

(84) Designated Contracting States: CH DE ES FR GB LI NL SE (30) Priority: 25.09.1997 GB 9720443 20.03.1998 GB 9806046 (71) Applicant: University of Bristol Bristol BS8 1TH (GB)	(72) Inventors: MILLS, Robin, Walter Devizes,Wiltshire SN10 5AX (GB) JANDT, Klaus, Dieter Bristol BS35 4QF (GB) (74) Representative: Hogg, Jeffery Keith  Withers & Rogers,Goldings House,2 Hays Lane London SE1 2HW London SE1 2HW (GB)