Low temperature microwave characteristics of 0.1μm gate-length pseudomorphic In/sub 0.52/Al/sub 0.48/As/In/sub x/Ga/sub 1-x/As (x=0.85 and 0.95) MODFET's

We have studied the microwave characteristics of 0.1μm gate-length pseudomorphic In/sub 0.52/Al/sub 0.48/As/In/sub x/Ga/sub 1-x/As (x=0.85 and 0.95) modulation-doped field-effect transistors (MODFET's) at 300 K and lower temperatures down to 77 K. A maximum f/sub T/ of 151 GHz has been measured for a 0.1×55 μm/sup 2/ gate In/sub 0.52/Al/sub 0.48/As/In/sub 0.85/Ga/sub 0.15/As MODFET at 77 K and this represents an improvement of 33% over the room temperature value. This behavior has been analyzed.