Bulk oscillation by tunnel injection

Abstract

In this paper a fundamental oscillating frequency of 129 GHz is obtained with a GaAs pn junction diode in which avalanche current co-exists with tunnel effeetl These GaAs diodes are produced by the solution growth method. Oscillations are seen when the diodes are pulsed into reverse bias. The low breakdown voltages observed require consideration of both tunneling and avalanche current components. In 1958, the negative resistance diode oscillator using both the avalanche phenomena and transit time effect in pn junction has been proposed by W. T. Read and by J. Nishizawa et al independently, and a large number of experimental reports concerning the above oscillator operating at microwave and mm wave frequencies have been published. It is necessary especially for obtaining oscillation with good efficiency in mm wave region that the transit time of the tunneling or avalanche injecting region be very small compared with the transit time layer width. In pn junctions if the depletion layer is of the order of the mean free path of carrier ionization, injection current flows by tunneling and not by avalanche. Therefore, by our experiment higher frequency oscillation is expected by combining tunnelling injection with transit time. Moreover the tunnelling injection can reduce the applied voltage for the oscillation and 129 GHz can be obtained with only 8 volt. The efficiency is expected to be increased with a pnin structure which is now being studied.