Fabrication of GaAs Gunn diodes using trench method

We developed the improved fabrication technology using the trench method for a graded-gap injector GaAs Gunn diode to avoid the formation of cracks which are caused by the difference in the thermal expansion coefficients between the GaAs epi-layer and the gold integral heat sink. We observed the negative-differential-resistance in the fabricated Gunn diode. The process we developed facilitates further process and handling because of the integral heat sink with thickness of 60 mum. Also, the formation of cracks in GaAs epi-layer was reduced during ohmic alloy process because of the reduced stress between the epi-wafer and the gold integral heat sink.