Silicide Metallization of Aluminum Nitride Substrates for High-Temperature Microelectronics

Abstract

A novel metallization for aluminum nitride substrates to package silicon carbide integrated circuits for use at temperatures up to 600°C was investigated. Chemical equilibrium calculations were used to determine the chemical compatibility of several refractory and transition metal disilicides with AlN. Tungsten disilicide, niobium disilicide, and titanium disilicide were selected for thin film deposition studies. WSi₂, NbSi₂, and TiSi₂ thin films were deposited by RF sputtering on AlN substrates and heat treated at 900°C, 1000°C, and 1200°C in an argon atmosphere. Sheet resistivities were measured and interface stabilities and structures were characterized by scanning and transmission electron microscopy imaging, electron diffraction, and energy dispersive x-ray microanalysis spectroscopy. The results show that metal silicides appear to be promising as metallization for aluminum nitride for use at temperatures above 600°C.