(19)

(11)

EP 0 435 963 A1

(12)

(43) Date of publication: 10.07.1991 Bulletin 1991/28 (21) Application number: 90903305.0 (22) Date of filing: 19.02.1990

(51) International Patent Classification (IPC):  H01L 35/ 20( . ) H01L 35/ 32( . ) (86) International application number: PCT/AU1990/000065 (87) International publication number: WO 1990/009682 (23.08.1990 Gazette 1990/20)

(84) Designated Contracting States: AT BE CH DE DK ES FR GB IT LI LU NL SE (30) Priority: 17.02.1989 AU 19890002794 (71) Applicant: NICROBELL PTY LIMITED Lidcombe, NSW 2141 (AU)	(72) Inventor: BURLEY, Noel, Arthur Mitcham, VIC 3132 (AU) (74) Representative: Jenkins, Peter David  PAGE WHITE & FARRER 54 Doughty Street London WC1N 2LS London WC1N 2LS (GB)