Depletion mode modulation doped Al0.48In0.52As-Ga0.47In0.53As heterojunction field effect transistors

We report the first demonstration of a depletion mode modulation doped Ga
0.47
In
0.53
As field effect transistor. This transistor combines the advantage of modulation doping and the superior material characteristics of Ga
0.47
In
0.53
As. DC transconductances of 31 mmho/ mm at 300 K and 69 mmho/mm at 77 K have been measured for a device with 5.2µm gate length and 340 µm gate width. An enhanced drift mobility is responsible for 88 percent of the improvement in the transconductance at 77 K and the remaining 12 percent is attributed to an improved ohmic contact. A high performance modulation doped Ga
0.47
In
0.53
As FET is expected to play an important role in very high speed digital and analog applications.