Properties of Sputtered Tungsten Silicide for MOS Integrated Circuit Applications

Abstract

Feasibility of the use of as gate electrode and electrical interconnecting material has been investigated. Properties of as‐deposited and annealed thin films of have been studied to determine their compatibility with integrated circuit fabrication processes. Thin films of were deposited by sputtering on oxidized silicon, with and without a coating of poly‐Si. As‐deposited films were amorphous, with a resistivity of . Upon annealing above 900°C in , the films became polycrystalline. The resistivity decreased and the average grain size increased as a function of time and temperature. A minimum resistivity of 10⁻⁴ Ω‐cm was obtained. Chemical reagents commonly used for cleaning and etching, when used with , showed behavior similar to poly‐Si. Al contacts to were stable up to 600°C for structure and up to 550°C for structure. These are significantly higher than the temperatures commonly used for sintering Al contacts to Si. Thermal oxidation of films in steam in the temperature range of 1000°–1200°C was performed and good quality was grown. Finally gate MOS devices were fabricated and characterized.