Morphological studies of silicon carbide thin film deposited by very high frequency - plasma enhanced chemical vapour deposition through gas dilution adjustment

Abstract

Dilution of gas was deployed to investigate the surface morphology and the surface topography of Silicon Carbide (SiC) film deposited using Very High Frequency – Plasma Enhanced Chemical Vapour Deposition (VHF-PECVD) technique. The deposition process of SiC thin film was performed with 150 MHz excitation frequency and 20 W radio frequency (RF) power. The argon and hydrogen carrier gas dilution was set to 5 sccm. Silane (SiH4) and methane (CH4) functioned as precursor gases and their flow rates were fixed at 2 and 8 sccm, respectively. Direct observations revealed that the surface morphology of deposited nanostructured-silicon carbide (ns-SiC) films in all samples had layer-island structure with varied island density and size formation above the critical layer thickness. Next, surface topography and roughness of the deposited SiC films were examined using Atomic Force Microscopy (AFM) in non-contact mode. As a result, all samples displayed different roughness, surface topography structure, and average grain diameter.