Electron and hole photocurrent effects on IMPATT oscillators

The effect of the magnitude and composition of leakage current on IMPATT oscillator performance is experimentally and theoretically evaluated. The principal effect of leakage current is to cause a reduction in the diode RF power output and an increase in the frequency of oscillations. The electron dominated leakage currents are more effective in reducing the RF power output and increasing the frequency of oscillations of an Impatt oscillator compared to leakage current dominated by holes. For experimental demonstration of leakage current effects flat profile, single drift region Impatt diodes were fabricated. A He-Ne laser was used as an optical source and the composition of leakage current with this source is changed by fabricating two types of devices. One with junction side down or flip chip to generate hole dominated leakage current and other with junction side up or top mounted to generate electron dominated leakage current.