A thermally induced avalanche failure mechanism in GaAs Gunn devices

High duty cycle and CW Gunn effect epitaxial devices are subject to premature failure due to avalanching induced by temperature gradients produced across the active layer. These temperature gradients are seen to effectively worsen existing doping gradients which initiate switching at a reduced bias level. Increases in average temperature are seen to vary the nominal breakdown field which in some cases has been seen to rise by a factor of two over the temperature range from 300 to 450°K.