| 摘要 |
967,002. Semi-conductor devices. STANDARD TELEPHONES & CABLES Ltd. May 5, 1961, No. 16416/61. Heading H1K. After treating a semi-conductor body so that one area of its surface has an oxide coating and a second has not part of the second area and an adjacent part of the first area is etched away and a film of electrically conducting material deposited on the surface in such a way that the oxide coating masks part of the etched area from deposition. In making a transistor an oxide coated NPN arrangement is produced by diffusing first gallium and then phosphorus into the surface of an N type silicon body and subsequently heating it in wet oxygen. The resulting oxide coating is selectively removed by applying a photo-resist, exposing selected areas thereof to ultra-violet radiation, removing the unexposed photo-resist material and etching away exposed parts of the oxide layer in hydrofluoric acid. The body is next etched in a mix of hydrofluoric, nitric and acetic acids to the form shown in Fig. 1c in which only the masked part 2 of the N layer remains. After diffusing gallium into the exposed areas, gold-gallium alloy is vacuum evaporated to form layer 11 (Fig. 10). After etching to remove layer 11 and the oxide layer from N layer 2, aluminium is vacuum evaporated over the entire surface and then removed except from the centre of zone 2 by masking and etching as above. Finally, the device is heated to alloy the aluminium and gold-gallium to the N and P layers 2, 3 respectively. In an alternative method, after etching to the form shown in Fig. 1c, the centre of oxide layer 2 is removed and aluminium vapour deposited over the entire surface and heated to form contacts 14, 15 to the N and P layers (Fig. 2). Both methods are applicable to the production of a plurality of transistors on a single body which is later subdivided. |
