Material and mechanical characterization of PECVD deposited a-SiC:H with H<inf>2</inf> dilution

Abstract

In this paper, we report optical and mechanical properties of low temperature plasma enhanced chemical vapor-deposited (PECVD) amorphous hydrogenated silicon carbide (a-SiC:H) thin films. Initial screening of this process using hydrogen-dilution was performed with a two-level, three-parameter design of experiments (DOE) with eight samples. In this process regime, it was determined that the main parameters affecting silicon carbide (SiC) deposition were the RF power and the hydrogen flow rate. Based on the DOE results, a further set of four samples was prepared to modulate deposition rate and stoichiometry. Material characterization of these samples using Fourier transform infrared spectroscopy (FTIR), X-ray photolectron spectroscopy (XPS), surface profilometry and ellipsometry is presented. Further, to determine the mechanical properties, cantilevers were fabricated and characterized using scanning electron microscopy (SEM) and laser Doppler vibrometry (LDV). Based on the resonant frequency measurement and film density, the Young's modulus for the films was determined.