Sub-half-micrometer pseudomorphic InP/In/sub x/Ga/sub 1-x/As/InP HEMT's (0.74/spl les/x/spl les/0.81) with very high fT values

In the recent past, strained Al-free InP/In/sub x/Ga/sub 1-x/As/InP high electron mobility transistors (HEMT's) with x>53% and L/sub G//spl ges/0.5 μm have shown very good performance mainly caused by the exceptional transport properties of electrons in In-rich In/sub x/Ga/sub 1-x/As-channel layers. We report about new results for highly strained devices with L/sub G/<0.5 μm. Thereby, current gain cut-off frequencies of f_T=100 GHz (130 GHz) for x=74% and L/sub G/=0.3 μm at 300 K (80 K) were achieved, respectively, whereas HEMT's with x=81% and L/sub G/=0.18 μm reached f_T=131 GHz (152 GHz) at the same temperatures. Moreover, the same devices showed off- and on-state drain-source breakdown voltages of V/sub DSbr/ (OFF)=10.5 and 5 V and V/sub DSbr/ (ON)=6 and 4 V, respectively. The combination of good RF and breakdown performance prove the potential of Al-free InP-based HEMT's for power applications at mm-wave frequencies.