PNNL

Abstract

Single crystal 6H-SiC wafers were fully amorphized at room temperature or 200 K using 1.0 or 2.0 MeV Au+ ion irradiation. The thickness of the amorphized layers has been determined using Rutherford backscattering spectrometry under ion channeling conditions. Microstructures of the irradiated SiC have been examined using cross-sectional transmission electron microscopy. The depth profiles of both the Si and C atoms have been studied using both x-ray photoelectron spectroscopy (XPS) and time-of-flight energy elastic recoil detection analysis. Neither Si nor C in the amorphized SiC exhibits a significant mass transport by diffusion during the irradiation and subsequent storage at room temperature. There is no observable phase segregation of either Si or C in the amorphized SiC. Ar+ ion sputtering leads to modifications of the composition, structure and chemical bonding at the 6H-SiC surface. The Si-Si bonds at the sputtered surface (amorphized) do not appear, as suggested by the XPS; however, Raman backscattering data reveals the existence of the Si-Si bonds in the bulk amorphized SiC, in addition to the C-C and Si-C bonds that the XPS also identified.