FIELD EFFECT TRANSISTOR

摘要

PROBLEM TO BE SOLVED: To provide an alternative form of an FET capable of exhibiting an improved value of current gain cutoff frequency fT. SOLUTION: The field effect transistor (FET) is of the type which employs base biasing to depress the intrinsic contribution to conduction and reduce leakage current. It incorporates four successive layers 102 to 108: a p+InSb base layer 102, a p+InAlSb barrier layer 104, a π intrinsic layer 106 and an insulating SiO2layer 108; p+source and drain regions 110 and 112 are formed in the intrinsic layer 106 by ion implantation. The FET is an enhancement mode MISFET 100 in which biasing establishes the FET channel in the intrinsic layer 106. The insulating layer 108 has a substantially flat surface supporting a gate contact 116. This avoids or reduces departures from channel straightness caused by intrusion of a gate groove, and enables a high value of current gain cutoff frequency to be obtained. COPYRIGHT: (C)2011,JPO&INPIT