Noise performance of pseudomorphic AlGaAs/InGaAs/GaAs high electron mobility transistors with wide head T-shaped gate recessed by electron cyclotron resonance plasma etching

Passivated 0.15 mu m pseudomorphic high electron mobility transistors (PHEM Ts) were fabricated by combining a wide head T-shaped gate, formed using a doss split method of electron beam lithography, with a short source-gate se paration, using formed an electron cyclotron resonance dry recess etching p rocess. The threshold voltage of the devices showed 50 mV variation across three-inch wafers. The extrinsic transconductance and cutoff frequency of t he PHEMT devices were 688 mS/mm and 82.6 GHz, respectively. The lowest mini mum noise figure, NFmin, of the PHEMT devices was observed around 80% of th e saturation drain current at 30 GHz and V-ds = 7 V. The devices exhibited a NFmin as low as 0.94 dB with an associated gain of 9, 1 dB at 30 GHz. Thi s noise figure value is the lowest data ever reported for a PHEMT device us ing a dry recess process.