The effect of gate-length variation on DC and RF performance of InAs/AlSb HEMTs, biased for low DC power consumption or high gain, is reported. Simultaneously fabricated devices, with gate lengths between 225 nm and 335 nm, have been compared. DC measurements revealed higher output conductance g(ds) and slightly increased impact ionization with reduced gate length. When reducing the gate length from 335 nm to 225 nm, the DC power consumption was reduced by approximately 80% at an fr of 120 GHz. Furthermore, a 225 nm gate-length HEMT biased for high gain exhibited an extrinsic fr of 165 GHz and all extrinsic of 115 GHz, at a DC power consumption of 100 mW/mm. When biased for low DC power consumption of 20 mW/mm the same HEMT exhibited an extrinsic fr and f(max) of 120 GHz and 110 GHz, respectively. (c) 2007 Elsevier Ltd. All rights reserved.