A tunnel emission triode

Active solid state triode structures have been made which oscillate up to 42 mcs. Power gain is achieved by means of a form of controlled internal field emission. The structure consists of two metallic stripes in contact with a single crystal of n-type Ge and separated from each other by a thin insulating layer of Al2O3. Under proper biases either metal electrode may be used to control injection of electrons into the space charge region existing in the Ge (which serves as a collector). A brief discussion of the theory of the device and the anticipated small signal equivalent circuit will be given. This will be compared with detailed measurements of the small signal four terminal a.c. parameters taken as functions of frequency and bias levels. Static characteristics will also be presented as a function of temperature, from which the temperature dependence of the input I-V characteristics and current transfer ratio will be determined. Preliminary measurements of power gain vs. frequency, which have shown gain of 10 db at 10 Mc, will also be presented.