InP-based self-aligned normally-off superlattice-insulated-gate field-effect transistor

An InP-based normally-off superlattice-insulated gate field-effect transistor (SIGFET) is developed using a self-aligned implant process. The new gate structure reduces the gate current significantly and yields a sharp pinch off. A SIGFET with 0.7 μm gate length delivers more than 800 mA/mm of drain current at 2 V of forward gate bias and yields an f
_T
as high as 42 GHz. An explanation for a new kink effect is also proposed.