Power pHEMTs operating at zero gate bias

The first development results for zero gate bias operation power pHEMTs have been submitted. High power transistors with Γ- type gate with gate length and width about 0.3 μm and 0.8 mm demonstrate specific output power exceeding 1.6 W/mm associated gain higher than 10 dB and efficiency higher than 40% at 10 GHz in pulse mode at +0.2 to -0.2 V gate bias operation. The possibility of lowering the input resistance in such devices by introducing a special embedment in the field of ohmic contacts has been investigated.