Gate Length Dependence of DC and Microwave Properties of Sub- micron In sub (0.53) Ga sub (0.47) As HIGFETs.

We have fabricated In sub (0.52) Al sub (0.48) As/In sub (0. 53) Ga sub (0.47) As/InP heterostructure insulated gate FETs (HIGFETs) with gate lengths from 1.1microns to 0.2microns, and characterized their electrical performance at dc and microwave frequencies. The refractory-gate, self-aligned process, applied to devices with In sub (0.53) Ga sub (0.47) As channels, yields an unprecedented combination of very high speed and excellent uniformity. HIGFETs with L sub g = 0.6microns showed average peak transconductance g sub m of 528 mS/mm and unity-current- gain cutoff frequency f sub t of 50 GHz. The uniformity of g sub m was better than 1%, and the voltage of the g sub m peak was uniform to +- 30 mV. HIGFETs with L sub g = 0.3microns showed f sub t up to 63 GHz, but suffered from serious short- channel effect, due to excessive thickness of the InGaAs channel layer. A self-aligned technique for gate resistance reduction is shown to substantially improve microwave power gain.