High temperature annealing effects on the chemical and mechanical properties of inductively-coupled plasma-enhanced chemical vapor deposited a-SiC:H thin films

Abstract

This paper reports the impact of thermal annealing up to temperatures of 1200°C on the chemical and mechanical properties of hydrogenated amorphous silicon carbide (a-SiC:H) thin films. These layers were deposited using an inductively-coupled plasma-enhanced chemical vapor deposition process with methane, silane and argon as precursor gases. The results of mass effusion measurements up to 1000°C are presented and the temperature-dependent effusion characteristics are compared to changes in the Fourier-transform infrared spectra. Furthermore, a simple method is presented that enables us to detect the onset of nanocrystallization in the a-SiC:H films caused by the high temperature annealing. The changes in chemical and crystallographic properties are discussed and related to the mechanical thin film properties, such as a substantial increase in Young's modulus from 176 up to 267GPa, in hardness from 24 up to 34.5GPa, as well as in residual film stress from −683 up to +3800MPa. Additionally, the decrease in layer thickness to about 70% of the initial value and the increase in refractive index from 2.33 to 2.78 are explained.