DC and RF characterization of short-gate-length InGaAs/InAlAs MODFETs

Lattice-matched InGaAs/InAlAs MODFETs with gate lengths down to 0.15 mu m have been fabricated and characterized. A large discrepancy is found between the g/sub m/ measured at DC and microwave frequencies and is attributed to the finite time constant of electron emission from deep traps in the InAlAs. A maximum f/sub T/ of 112 GHz is measured on a 0.15- mu m gate-length device. Devices with more shallow recessed gates are found to have a 50% larger output conductance, which causes the devices to exhibit an f/sub T/ that is greater than f/sub max/.>