Direct determination of volume changes in ion-beam-irradiated SiC

Abstract

A single crystal 6H-SiC wafer was sequentially implanted in two areas at 873 and 295 K using 2.0 MeV Au2+ ions under off-axis conditions. Identical Au depth profiles, as a function of atomic areal density, were obtained for both irradiation temperatures. X-ray photoelectron spectroscopy (XPS) and analytical electron microscopy were used to determine the one-dimensional expansion in the amorphous state produced at 295 K relative to that in the slightly damaged state produced at 873 K, based on the Au reference markers. In addition, the redshift of the plasmon-loss peak in the electron energy loss spectroscopy (EELS) was used to measure the local density changes. Comparison of the three methods indicates that the XPS and EELS methods were the most reliable, yielding a volume expansion of (11.5±2)% for the amorphous state in 6H-SiC at 295 K. The volume expansion in the slightly damaged state at 873 K was determined to be 0.9% by EELS.