Investigation using transmission electron microscopy of the microstructure of TiN film formed by ion beam enhanced deposition under 90 keV Xe+ bombardment on an Si substrate

Abstract

In this work, the microstructure and composition of TiN film, formed by ion beam enhanced deposition (IBED) with 90 keV Xe + bombardment, and the interface between the TiN film and Si substrate were studied by cross-section analytical transmission electron microscopy. Images of the TiN film and TiN-Si interface are shown. Analysis of microdiffraction patterns and micro-energy-dispersive spectroscopy shows that there are amorphous layers of TiN and Si 80 nm thick at the TiN-Si interface; the TiN amorphous layer is close to the TiN film and the Si layer is near the Si substrate. It is seen from selected area electron diffraction patterns that most of the TiN grains have preferred orientation in a twinned relation with the {111} twin plane. Dark-field images of the TiN film show that the grain size is less than 0.8 nm. The TEM observations of the TiN film can be summarized as follows. (1) The TiN and Si amorphous layers at the TiN-Si interface are formed by Xe + bombardment. (2) Most of the TiN grains near the TiN-Si interface exist in a twinned relation with the {111} twin plane. (3) The TiN film is a nanometre film; the TiN grain size is less than 0.8 nm. (4) The energy of the xenon ions affects significantly the structure and thickness of the amorphous layers formed between the TiN and Si, and the size and orientation of the TiN grains. (5) Xenon ion bombardment with higher energy results in a preferred orientation and twin relation of TiN grains, and reduces the size of the TiN grains.