Trench MOS Schottky barrier rectifier with high k gate dielectric and reduced mask process for the manufacture thereof

摘要

A trench MOS Schottky barrier device has a metal oxide gate dielectric such as TiSi lining the trench wall to increase the efficiency of the elemental cell and to improve depletion in the mesa during reverse bias. A reduced mask process is used in which a single layer of titanium or other metal is deposited on an underlying gate oxide layer on the trench walls and directly atop the mesa between adjacent trenches. A common thermal treatment causes the Ti to diffuse into the SiO₂ gate oxide to form the TiO₂ gate and to form the TiSi Schottky barrier on the top surface of the mesa.