Characterization of tungsten silicide (WSix) film grown by chemical vapor deposition (CVD)

Abstract

The objective of this work is to evaluate a well-known low resistance refractory metal silicide such as tungsten silicide (WSi x ) for use as a gate electrode in order to achieve faster switching speed. However, the deposition of a WSi x film in high aspect ratio trenches is difficult in terms of step coverage as well as adhesion when using a low pressure chemical vapor deposition (LPCVD) technique. The deposition conditions need to be carefully tweaked to achieve satisfactory step coverage and film thickness. This paper focuses on the deposition conditions of WSi x films onto boron doped poly-Si gate material to achieve higher step coverage in the trenches.