TRANSMISSION ELECTRON-MICROSCOPY OF THE ALN-SIC INTERFACE

The AlN-SiC interface has been studied using high-resolution transmiss ion electron microscopy. Cross-section lattice images of the AlN-SiC i nterface have been analysed to establish the connection between image contrast and the atomic positions in the lattice. Assuming atomically abrupt and planar AlN-SiC interfaces, four possible atomic bonding con figurations are taken into account for SIC substrates with the (0001)( Si) orientation. Image simulations of these four interface models are compared with the experimental images. Considering variations at the i nterface of the image contrast, the basal-plane distance and the proje cted charge density, it is shown that the C-Al and Si-N bonds are in a greement with the experimental images and are not distinguishable unde r our experimental conditions. The other two possibilities, involving C-N and Si-Al bonds, are not consistent with our observations.