High performance MESFET with multiple quantum wells.

摘要

A superheterojunction Field Effect Transistor (FET) with a multi-region channel on a Silicon (Si) substrate (204). The FET is a Metal Semiconductor FET (MESFET) or, alternatively, a Junction FET (JFET). The multi-region channel has: a first region (250) of Si extending from the FET's source to a point under the FET's gate, beyond the gate's midpoint; a second region extending from the first region to the FET's drain (240), comprised of a superlattice of alternating Si and SiGe layers (206); and, a third region (202) of Si extending under the first two regions from the source to the drain. The first region has a laterally graded dopant that creates an accelerating electric field. The superlattice structure increases electron mobility and transit velocity.