(19)

(11)

EP 0 400 110 A1

(12)

(43) Date of publication: 05.12.1990 Bulletin 1990/49 (21) Application number: 89911589.0 (22) Date of filing: 04.10.1989

(51) International Patent Classification (IPC):  H01L 39/ 22( . ) (86) International application number: PCT/GB1989/001178 (87) International publication number: WO 1990/004266 (19.04.1990 Gazette 1990/09)

(84) Designated Contracting States: CH DE FR IT LI NL (30) Priority: 05.10.1988 GB 19880023399 (71) Applicant: THE GENERAL ELECTRIC COMPANY, p.l.c. London W1A 1EH (GB)	(72) Inventor: PEROLD, Willem, Jacobus 7130 Somerset West (ZA) (74) Representative: George, Sidney Arthur  The General Electric Company p.l.c. GEC Patent Department Waterhouse Lane Chelmsford, Essex CM1 2QX Chelmsford, Essex CM1 2QX (GB)