| 摘要 |
1,019,849. Semi-conductor devices. STANDARD TELEPHONES & CABLES Ltd. Dec. 24, 1963, No. 50882/63. Heading H1K. A planar semi-conductor device is produced by forming a junction using an oxide diffusionmask and then forming a fresh layer of oxide beneath the mask. This fresh layer of oxide is less contaminated than the layer used as the diffusion-mask. As shown, a wafer 1 of N-type silicon has a layer 2 of silicon oxide formed on its surface by heating in steam or oxygen, or by the pyrolytic decomposition of a compound containing silicon and oxygen. A window 3 is photo-resist etched through the oxide layer and an acceptor impurity, preferably combined with silicon, is applied to the exposed surface, and the wafer is then heated in an oxidizing atmosphere. The impurity first alloys with, and then diffuses into, the wafer 1 to form P-type region 5, and the exposed surface of the wafer is simultaneously reoxidized. The wafer is then heated in an oxidizing atmosphere to a temperature below that used for the diffusion to form a fresh layer of oxide 7 below the oxide mask 2. A window 10 is then etched in both oxide layers 2, 7, and ohmic contacts 8, 9 and leads 11, 12 are applied to form a diode. A transistor can be manufactured by diffusing an N-type emitter region into the P-type diffused region, which forms the base region, before forming the fresh layer of oxide. A plurality of devices of either type may be simultaneously produced in a single wafer which is then divided up to form individual units. |
