Single- and double-heterojunction pseudomorphic In/sub 0.5/(Al/sub 0.3/Ga/sub 0.7/)/sub 0.5/P/In/sub 0.2/Ga/sub 0.8/As high electron mobility transistors grown by gas source molecular beam epitaxy

In/sub 0.5/(Al/sub 0.3/Ga/sub 0.7/)/sub 0.5/P/In/sub 0.2/Ga/sub 0.8/As single- and double-heterojunction pseudomorphic high electron mobility transistors (SH-PHEMTs and DH-PHEMTs) on GaAs grown by gas-source molecular beam epitaxy (GSMBE) were demonstrated for the first time. SH-PHEMTs with a 1-μm gate-length showed a peak extrinsic transconductance g/sub m/ of 293 mS/mm and a full channel current density I
_max
of 350 mA/mm. The corresponding values of g/sub m/ and I
_max
were 320 mS/mm and 550 mA/mm, respectively, for the DH-PHEMTs. A short-circuit current gain (H/sub 21/) cutoff frequency f
_T
of 21 GHz and a maximum oscillation frequency f
_max
of 64 GHz were obtained from a 1 μm DH device. The improved device performance is attributed to the large /spl Delta/E/sub c/ provided by the In/sub 0.5/(Al/sub 0.3/Ga/sub 0.7/)/sub 0.5/P/In/sub 0.2/Ga/sub 0.8/As heterojunctions. These results demonstrated that In/sub 0.5/(Al/sub 0.3/Ga/sub 0.7/)/sub 0.5/P/In/sub 0.2/Ga/sub 0.8/As PHEMT's are promising candidates for microwave power applications.