Halbleitergeraet

摘要

1,143,633. Transistors. MATSUSHITA ELECTRONICS CORP. 7 March, 1966 [10 March, 1965], No. 9937/66. Heading H1K. The transistor of Figs. 3 (not shown) and 4 is distinguished from common diffused planar transistors by the three features: (a) the concentration of significant impurities in the base layer 7 where the collector-base junction 8 meets the surface of the body is such as to give a low impurity gradient and consequent high breakdown voltage; (b) the emitter-base junction 9 is formed by uniform diffusion over the entire surface of the body so that lattice disturbance (and consequent loss of injection efficiency) at the junction caused by the high doping level of the emitter region is reduced compared with the case of localized diffusion to form an imbedded emitter region, (c) the capacitance between contact areas 151, 161 and the substrate (collector) is kept low by the provision of two-intervening PN junctions 81, 91. In an example, the manufacturing stage of Fig. 7 is reached by diffusing antimony (from dry nitrogen saturated with antimony tetroxide) into the surface of a 1 ohm cm. N-type silicon wafer to form a heavily doped layer 2, by oxidizing the surface in wet oxygen, by removing a rectangular annulus of the oxide 3 and diffusing in boron (from nitrogen saturated with boron monoxide) to form the region 5, and then by diffusing gallium through the oxide film now existing over the entire surface and through the heavily doped N-type layer to form an underlying P-type layer 7. The transistor shown by stepped section in Fig. 4 is obtained by photoresist etching a groove 10 in the semi-conductor body, by completely removing oxide films and growing a new oxide film 11 through which holes are made to expose the emitter region 2 and base region 5, by evaporating aluminium over the upper surface of the body, by removing excess metal by photo-etching to leave emitter and base contacts 15 and 16 which extend over the oxide to provide regions to which leads 17, 18 are attached, and by removing the incidentally formed diffused layers and oxide layers from the lower surface of the body.