Improvements in semiconductor devices

摘要

1,105,177. Semi-conductor rectifiers. GENERAL ELECTRIC CO. 13 Aug., 1965 [31 Aug., 1964], No. 34821/65. Heading H1K. A semi-conductor rectifier comprises at least three layers, adjacent layers being of unequal resistivities, and forming at least one PN junction, and means to increase the surface breakdown voltage comprising a relatively thick region surrounding a thinner inner region where avalanche breakdown occurs initially. Fig. 1 shows a PIN diode device of silicon or germanium in which the central region 16 underlying electrode 18 has a thin intrinsic layer 12 and is designed to provide the desired rectifier and avalanche breakdown characteristics. In the surrounding region 17 the intrinsic layer 12 is thicker to prevent surface breakdown. A controlled rectifier comprising P, N, N-, P, N layers is also described in which the thickness of the N- layer is increased in the outer region to achieve the same purpose; the impurity concentrations of the layer may be 1020, 1017, 1013, 1018 and 1021 respectively. The device may be produced by diffusing phosphorus and boron into high resistivity silicon.