Fabrication and characterisation of double heterojunction In 0.48Ga 0.52P/In 0.20Ga 0.80As high electron mobility transistors grown by solid-source molecular beam epitaxy

Abstract

Double heterojunction (DH) In 0.48Ga 0.52P/In 0.20Ga 0.80As pseudomorphic high electron mobility transistor (p-DHHEMT) structures were grown by solid-source molecular beam epitaxy (SSMBE) using a valved phosphorus cracker cell. Maximum drain current ( I DS max ) and transconductance ( G m) of 370 mA/mm and 360 mS/mm for the 1.25-μm device, and about 500 mA/mm and 440 mS/mm for the 0.35-μm device, were measured. The current–voltage ( I– V) characteristic shows that possible formation of parasitic channels at the InGaP/GaAs interface could give rise to ‘soft’ pinch-off behaviour. Cut-off frequency ( f T) of 12 GHz and maximum oscillation frequency ( f max) of 33 GHz were achieved for the 1.25-μm device, and f T of 40 GHz and f max of 130 GHz were measured for the 0.35-μm device.