III-V Heterostructure Microelectronics

We report the successful fabrication of InGaAs FETs with heterostructure-insulated gates suitable for high-speed, enhancement-mode operation. InGaAs is enticing as an FET channel because of its high mobility, high peak carrier velocity, and widespread use in long-wavelength optoelectronic devices, but its small Schottky barrier has prohibited development of a MESFET technology. Junction FETs and FETs with insulator-assisted Schottky gates have been demonstrated for depletion-mode operation, but forward currents have been excessive for enhancement-mode operation.