Noise Performance of Pseudomorphic AlGaAs/InGaAs/GaAs High Electron Mobility Transistors with Wide Head T-Shaped Gate Recessed by Electron Cyclotron Resonance Plasma Etching

Abstract

Passivated 0.15 µm pseudomorphic high electron mobility transistors (PHEMTs) were fabricated by combining a wide head T-shaped gate, formed using a dose split method of electron beam lithography, with a short source-gate separation, using formed an electron cyclotron resonance dry recess etching process. The threshold voltage of the devices showed 50 mV variation across three-inch wafers. The extrinsic transconductance and cutoff frequency of the PHEMT devices were 688 mS/mm and 82.6 GHz, respectively. The lowest minimum noise figure, NF min, of the PHEMT devices was observed around 80% of the saturation drain current at 30 GHz and V ds = 2 V. The devices exhibited a NF min as low as 0.99 dB with an associated gain of 9.1 dB at 30 GHz. This noise figure value is the lowest data ever reported for a PHEMT device using a dry recess process.

Evolution and recent advances in RF/microwave transistors

“…GaAs MHEMTs show only slightly higher noise figures than InP HEMTs. State of the art GaAs PHEMTs with noise figures less than 1 dB up to 30 GHz have been reported[41]. In general, FETs are less noisy compared to bipolar transistors.…”