HETEROJUNCTION FIELD-EFFECT TRANSISTOR

摘要

PROBLEM TO BE SOLVED: To provide a heterojunction field-effect transistor in which a leakage current is small and a breakdown strength is high. SOLUTION: The heterojunction field-effect transistor includes: an AlN buffer layer; an AlGaN composition inclined layer; a GaN channel layer; and an AlGaN barrier layer, which are successively layered on an insulating substrate. The AlGaN composition inclined layer reduces an Al density from the lower face toward the upper face, the AlGaN barrier layer has a larger Al density by 15% or more than the Al density on the upper face of the AlGaN composition inclined layer, and a pseudo p-type sheet carrier density obtained by spontaneous polarization and a piezoelectric effect in the AlGaN composition inclined layer is 3×1012cm-2through 4×1012cm-2. COPYRIGHT: (C)2011,JPO&INPIT