Submicron RIE recessed InGaP/InGaAs doped-channel FETs

Abstract

High performance submicron In/sub 0.49/Ga/sub 0.51/P/In/sub 0.15/Ga/sub 0.85/As doped-channel heterostructure field effect transistors (HFETs) have been developed and characterized. In order to achieve a high uniformity of device characteristics crossing the wafer, BCl/sub 3/+CHF/sub 3/ reactive ion etching technology in gate-recessed process is applied to fabricate the InGaP/InGaAs doped-channel FETs. The unity current gain cut-off frequency (f/sub T/), maximum frequency of oscillation (f/sub max/), and threshold voltage have been investigated versus the gate-length. The improved microwave performance in smaller gate-length devices is mainly associated with the reduction of the input capacitance. The 0.2 /spl times/ 200-/spl mu/m/sup 2/ gate-dimension DCFET exhibits a saturated P/sub out/ of 18.9 dBm, a power density of 388 mW/mm, a PAE of 35%, and an associated gain of 14 dB at 2.4 GHz.