Tungsten and tungsten silicide (WSi/sub x/) as gate materials for trench MOSFETs

Abstract

High-density and high-speed MOS-integrated devices require low gate resistance. Metallization of the gate electrodes reduces gate sheet resistance, improves switching efficiency, reduces distributed RC propagation delay, and possibly enhances device reliability when delivering power to large inductive loads using large area power MOSFETs. Tungsten (W) and/or tungsten silicide (WSi/sub x/) gates have been developed with this goal for trench power MOSFET applications by chemical vapor deposition (CVD). The deposition techniques employed resulted in good step coverage and provide promising structural integrity against silicon (Si) or W diffusion. The paper discusses the metal/silicided gate development using various approaches.