InGaN/(GaN)/AlGaN/GaN normally-off metal-oxide-semiconductor high-electron mobility transistors with etched access region

Abstract

The proposal and processing aspects of the prove-of-concept InGaN/GaN/AlGaN/GaN metal-oxide-semiconductor (MOS) high-electron mobility transistor with etched access regions are addressed. Full strain and decent quality of the epitaxial system comprising 4 nm In 0.16 Ga 0.84 N/3 nm GaN/5 nm Al 0.27 Ga 0.73 N are observed using a high-resolution transmission-electron microscopy and by deformation profile extractions. Large negative polarization charge in the MOS gate stack provides the HEMT normally-off operation, while free electrons are populated at access regions after etching. Consecutive passivation by 10 nm Al 2 O 3 together with annealing at 300 °C improved the Al 2 O 3 /semiconductor interface, with the threshold voltage (V T ) reaching 1 V. Improvements of the present concept in comparison to the previous one with a gate recess were proved by showing the decreased drain leakage current and increased breakdown voltage.

Polarization‐Engineered n+GaN/InGaN/AlGaN/GaN Normally‐Off MOS HEMTs

“…Low hysteresis observed for t ox = 10 nm has been increased for t ox = 30 nm as larger V GS swing and thicker gate insulator pronounce V T instability . As will be reported elsewhere, less studied un‐optimized Al 2 O 3 /InGaN interface may demonstrate more trapping behavior if compared with more established Al 2 O 3 /AlGaN system . In Figure we show output characteristics of the normally‐off n + GaN/InGaN/AlGaN/GaN MOS HEMT B with t ox = 10 nm.…”