| 摘要 |
1,102,164. Semi-conductor devices. TEXAS INSTRUMENTS Inc. 14 April, 1965 [15 April, 1964], No. 16021/65. Heading HlK. In making a semi-conductor device impurities are simultaneously diffused into a semi-conductor wafer from overlapping layers respectively containing impurities of opposite conductivity types and different diffusion characteristics to form side-by-side layers of opposite conductivity types extending to different depths. In a typical embodiment a planar NPN transistor is made in multiple by first depositing phosphorus doped oxide on an N-type silicon wafer from a gaseous mixture of tetraethylorthosilicate and phosphorus oxychloride or tribromide and reducing it to isolated areas (2 in Fig. 1) by photoresist and etching steps. Then a layer of gallium doped silicon oxide is deposited from a mixture of the orthosilicate with triethyl gallium and etched back to form areas 3 covering and extending around areas 2. Next undoped silicon oxide 4 is deposited by pyrolytic decomposition of silanes over the doped layers and the assembly heated to 1200‹ C. to diffuse in the gallium and phosphorus to form base region 6 and emitter 5. Apertures are then provided in the layers to accommodate electrodes 7, 8 formed by deposition and photo-resist and etching steps, and the wafer divided into single elements for attachment to headers 9. Formation of PNP structures using oxide layers containing phosphorus and boron as dopants is also suggested, the boron doping being achieved by incorporating tripropyl borate or boron tribromide in the tetraethylorthosilicate. The method is also said to be applicable to germanium and gallium arsenide wafers.
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