part with degenerate dotiertem halbleiterkoerper and very duenner pn - transition area and procedure for manufacture of this halbleiterbauelements, especially tuneldiode or esaki diode

摘要

966,989. Semi-conductor devices. INTERNATIONAL BUSINESS MACHINES CORPORATION. July 31, 1961 [Nov. 21, 1960], No. 27670/61. Drawings to Specification. Heading H1K. In a tunnel diode, surface current leakage is reduced by increasing the resistivity, i.e. to above degeneracy of the semi-conductor material where the junction is exposed to the surface. For example in P-type germanium it is stated that by increasing the resistivity from 0.003 ohm cm. (5 x 10SP19/SP impurity centres per c.c.) to 0.03 ohm cm. (less than 10SP19/SP centre per c.c.) in the surface region near a PN junction, then the greater part of the tunnelling current will flow within the main body of the material. The corresponding figures for N-type germanium are 0.001 to 0.01 ohm cm. One method of obtaining such a tunnel diode consists in doping germanium with arsenic until a concentration of 5 x 10SP19/SP impurity atoms per c.c. is reached and then heating this material for thirty minutes at a temperature of 600‹ C. under a pressure of 10-SP7/SP m.m. of mercury, which reduces the surface impurity concentration to about 10SP16/SP. A narrow junction (less than 150 Angstroms) is then made by allowing to the above N type germanium an indiumgallium mixture. A brief reference is also made to an epitaxial-growth method of making the junction.