An investigation of the current gain of a drift transistor at frequencies up to 105 Mc/s

The complex internal short-circuit current gain, ¿d, of a type 2N247 plane alloy-junction germanium transistor has been determined from measurements of the external short-circuit current gain, by taking account of the effects of the emitter and collector depletion-layer capacitances and the ohmic base resistance. Measurements have been made up to 105 Mc/s and over a range of emitter current from 50 ¿A to 8 mA. It has been found that the loci of ¿d may be interpreted in terms of Kroemer´s theoretical treatment, which is based on the existence of a uniform drift field across the base. The value of ¿V/kT is found to be 5 at room temperature.