PNNL

Abstract

The microstructural features of highly-damaged 4H-SiC implanted with Al22? ions at 450 K have been studied using transmission electron microscopy (TEM) and electron energy-loss spectroscopy (EELS). Conventional TEM images reveal that the crystalline SiC domains are highly strained/distorted when the relative disorder on the Si sublattice ranges between about 0.4 and 0.8, as determined by Rutherford backscattering spectrometry in channeling geometry (RBS/C). As the relative disorder approaches to 1.0, the high strain contrast appears to be relieved and localized amorphized domains are observed. Plasmon-loss energy shows a red-shift following the implantation, and the magnitude of the red-shift increases with increasing relative disorder. Based on the red-shift, the estimated volume expansion is ~ 8% for highly-damaged crystalline SiC and ~ 16% for the amorphous state. Energy-loss near-edge-structure (ELNES) of both the C and Si K-edge reveals the existence of Si-Si and C-C bonding in the Al22?implanted SiC.