HIGH BREAKDOWN VOLTAGE INGAAS/INALAS HFET USING IN0.5GA0.5P SPACER LAYER

A highly strained In0.5Ga0.5P spacer is introduced into an HFET grown by MOVPE on InP substrate for the first time. Despite the large lattice mismatch and the group V exchange at the channel-spacer interface the transport data are not affected (mu(H), 300K = 11 300 cm(2)/Vs, n(s) = 2 x 10(12)cm(-2)). However the large bandgap energy of InGaP results in improved gate leakage, drain conductance and drain breakdown. At V-DS = 10V a voltage gain of nu(u) > 100 is maintained. HFETs with L(g) = 0.7 mu m exhibit g(m) = 360mS/mm, I-D, (max)(V-DS = 6V) = 550 mA/mm and a cutoff frequency f(max) of 150GHz. At V-DS = 5.5V an AC output power of 0.6W/mm is achieved indicating the capability for high power HFET application on InP substrates.