Electric field-responsive solid state devices

Abstract

Abstract 1,070,261. Semi-conductor devices. INTERNATIONAL BUSINESS MACHINES CORPORATION. May 26, 1964 [June 10, 1963], No. 21796/64. Heading H1K. The invention is based on the discovery that when an electric field in excess of 2000 volts/cm. is set up in a crystal of gallium arsenide, the current flow between a pair of electrodes on the body fluctuates at microwave frequency. In general the fluctuations are random noise but if the electrodes are at the ends of a body whose length L lies between 2 x 10<SP>-2</SP> and 1 x 10<SP>-4</SP> cm. and the field is set up by applying a suitable potential difference to these electrodes, the current fluctuations are coherent oscillations with a frequency, or set of harmonic frequencies, given by f = nv/L, where / is the frequency, n is an integer and v is the carrier drift velocity. The claims are directed to a device (which need not be made of gallium arsenide) exhibiting the above effect and to the use of the effect as a method of generating microwave oscillations. In the drawings (not shown). Figs. 1 and 2 depict the electrical characteristics of the device; Fig. 3 an oscillator circuit consisting solely of the device, a source of D.C. power and a load; and Fig. 4 a jig which is used to provide a suitably dimensioned Ga As wafer with tin electrodes. In this jig the wafer is located between two tin spheres which are subsequently melted and alloyed to the wafer, the end product (Fig. 5a, not shown) being a cylinder consisting of two tin rods with a disc of gallium arsenide between them. This is subsequently shaped by grinding to a triangular cross-section, embedded in epoxy resin, the resin partly removed to expose one rectangular face of the triangular prism and attached by that face to a suitable insulating block carrying phosphor bronze contacts to the tin electrodes. The steps of this process are depicted in Figs. 5b to 5f (not shown).

Inventors

• 👤 John B Gunn

Bibliographic Details