Lg=100 nm InAs PHEMTs on InP substrate with record high frequency response

Abstract

A report is presented on 100 nm and 200 nm InAs PHEMTs on an InP substrate with a record fT performance. This result was obtained by reducing a parasitic delay associated with the extrinsic gate capacitances of the device, as well as by using an InAs sub-channel to improve carrier transport properties. In particular, a 100 nm InAs PHEMT exhibits excellent performance, such as gm,max=2 S/mm, fT=421 GHz and fmax=620 GHz at VDS=0.7 V. The device also shows a well-balanced fT and fmax in excess of 400 GHz, even at VDS=0.5 V. In addition, the device gains about 70 % improvement in fT as Lg shrinks down from 200 to 100 nm. The results obtained in this work should make this technology of great interest to a multiplicity of applications and guide a realistic path in trying to achieve a 1 THz fT from III-V HEMTs in the future.