High-transconductance beta -SiC buried-gate JFETs

Abstract

An improved performance buried-gate SiC junction field-effect transistor (JFET) has been fabricated and evaluated. This structure uses an n-type beta -SiC film epitaxially grown by chemical vapor deposition on the Si(0001) face of a p-type 6H alpha -SiC single crystal. The current in the n-type channel was modulated using the p-type alpha -SiC layer as a gate. Electron-beam-evaporated Ti/Au was utilized as an ohmic contact to the n-type beta -SiC layer, and thermally evaporated Al was used to contact the p-type gate. A maximum DC transconductance of 20 mS/mm was obtained, which is the highest reported for a beta -SiC FET structure. The experimental data are analyzed using a charge-control model. Calculated drain current versus drain voltage characteristics for a buried-gate JFET are in good agreement with experimental data.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>