Characteristics of Poly-Crystalline 3C-SiC Thin Films Grown for Micro/Nano-Electromechanical Systems by Using Single-Precursor Hexamethyldisilane

Abstract

This paper presents the growth conditions and characteristics of poly-crystalline 3C-SiC thin films for micro/nano-electromechaical systems (M/NEMS) applications. The growth of the polycrystalline 3C-SiC thin film on an oxided Si wafer was carried out by using atmospheric pressure chemical vapor deposition (APCVD) with a single-precursor of hexamethyldisilane (HMDS: Si2(CH3)6). This work was done for deposition conditions; the growth temperature and the HMDS flow rate were adjusted from 1000 to 1200 ◦C and from 6 to 8 sccm, respectively. Each sample was analyzed by using X-ray diffraction (XRD), Fourier transform-infrared spectroscopy (FT-IR), and reflection high energy electron diffraction (RHEED) to obtain an optimized growth temperature. A scanning electron microscopy (SEM), which measures the layer density, voids, and dislocations in a cross-section, was also used to obtain an optimized HMDS flow rate. Moreover, X-ray photoelectron spectroscopy (XPS) and glow discharge spectrometry (GDS) were used to evaluate the stoichiometry of the poly-crystalline 3C-SiC films, and the atomic ratio between Si and C was 1 : 1 from the surface to the interface. Finally, the effect of H2 addition was studied to reduce to surface roughness, and atomic force microscopy (AFM) and tunneling electron microscopy (TEM) were used to investigate the surface roughness and the SiC/SiO2 interface, respectively. From the results, the optimal growth conditions for the poly-crystalline 3C-SiC thin film were a deposition temperature of 1100 ◦C, a HMDS flow rate of 8 sccm, and a H2 flow rate of 100 sccm. The grown poly-crystalline 3C-SiC films had very good crystal quality without twins, defects, and dislocations.