Raman scattering and SEM studies of graphite and silicon carbide surfaces bombarded with energetic protons, deuterons and helium ions

Abstract

Experimental investigations on the chemical and physical effects of 10–15 keV H 1 +, D 1 + and He + ion bombardments to fluences up to 10 19 ions/cm 2 on graphite and SiC have been conducted using the techniques of Raman scattering and scanning electron microscopy (SEM). Raman scattering data for ion bombarded graphite reveal the formation of an amorphous surface layer as indicated by the appearance of a broad band in the spectrum centered at 1525 cm which replaces the bands due to microcrystalline carbon at 1585 cm −1 and 1360 cm −1. The microcrystalline structure could be partially restored upon vacuum annealing at 1040°C for several hours. A weak, broad band centered at 2150 cm also appears after bombardment which is indicative of the formation of − C = C− bonds. Surfaces of “KT” SiC were also amorphized on ion bombardment as indicated by changes in the Raman spectra. Chemical trapping of the incident h 1 + and D 1 + ions to form bulk C-H, C-D and Si-H species was observed. Preferential sputtering of Si leaving a carbon rich surface region also occurred. Blister formation was observed in the SEM studies.