Electronic Structure and Bonding at Interfaces Between cvd Diamond and Silicon

Abstract

The interfacial structure of CVD diamond grown on silicon was studied using spatially resolved electron energy loss spectroscopy (EELS) in a UHV STEM with a subnanometer probe size. Both the plasmon and core excitations in the bulk appear to be localized on this scale. Spatial maps of the different bonding configurations of carbon were obtained by forming images from transmitted electrons that had undergone energy losses characteristic of threefold and fourfold coordinated carbon. Films grown on both prescratched silicon and intermediate amorphous carbon layers were examined. In the latter case, diamond nucleation on a narrow sp2 a-C occurred. For diamond grown directly on silicon, at some regions of the interface, threefold coordinated defect states smaller than 1 nm are observed on the diamond side of the interface while at other regions along the interface the presence of an intermediate 2nm thick SiC layer preserves the fourfold coordination of the carbon.

Mapping of ELNES on a nanometre scale by electron spectroscopic imaging

“…diamond and amorphous carbon (Egerton & Whelan, 1974a;Berger et al, 1988). The results will be compared with the results which can be obtained on a field emission gun scanning transmission electron microscope (FEG-STEM) (Hunt & Williams, 1991;Muller et al, 1993Muller et al, , 1994.…”