HF characteristics of InP-based HFETs grown at extremely low temperatures of 300/spl deg/C and below

Heterostructure FETs with InP channel have been fully grown and processed at low temperature by MBE. Here we show that such structures are also feasible for microwave applications. InP-based HFETs with 20 nm InAlAs Schottky layer and 50 nm InP channel layer grown below 300/spl deg/C were processed and characterized at DC and RF. The devices show a maximum breakdown voltage above 10 V, f/sub t/=19 GHz and f/sub max/=40 GHz at 0.4 /spl mu/m gate length. The highest f/sub t//spl middot/L/sub G/-product was 10 GHz/spl middot//spl mu/m for a 1.2 /spl mu/m device.