| 摘要 |
1,270,226. Transistors. INTERNATIONAL BUSINESS MACHINES CORP. 4 Jan., 1971 [9 Jan., 1970], No. 261/71. Heading H1K. In making a transistor a layer of silicon dioxide and a superposed layer of silicon nitride are formed on the base region, an aperture opened in the layers and impurity diffused through it to form the emitter region, a further base contact aperture opened in the layers and metal deposited over the layers and in this aperture to form a base contact, a further layer of silicon dioxide deposited overall and then selectively etched to re-expose the emitter region and metal deposited on this layer and the emitter region to form an emitter contact. In the embodiment (Fig. 9) the metal layers 7, 10 are aluminium, or molybdenum on platinum, and the emitter is diffused prior to formation of the base contact apertures. Conventional processes, which are described, are used to form the oxide layers 2, 8a and nitride layer 3, and the first metal layer, 7 of aluminium, initially deposited overall, is removed from the emitter by etching in a specified phosphoric-nitric acid mix. In an alternative method the base contact and emitter diffusion apertures are formed simultaneously. Then a further layer of oxide is deposited overall, etched from the emitter aperture to allow the diffusion and subsequently from the base contact aperture. |
