Effects of titanium and aluminum incorporations on the structure of boron nitride thin films

Boron nitride (BN)-based composite thin films have been prepared by ion-beam-assisted deposition (IBAD) employing two electron-beam evaporators. Approximately 3-5 at.% of either Ti or Al was incorporated into the BN composite films. Fourier-transform infra-rid (FTIR) spectroscopy was used for phase identification of the BN composite films. The influences of the Ti and Al additions on the cubic phase formation in the BN films are reported. It has been found that Al incorporation has a strong negative effect on cubic BN (cBN) formation. No cubic phase can be obtained under the presently chosen ion-bombardment parameters. However, the disturbance of 3-5 at.% Ti addition, depending on the preparation conditions for the BN thin films, only shifts the threshold of the ion/atom ratio of the IBAD process, which is required for cBN formation to a higher value. In order to understand the different behaviors of the Ti and Al incorporations, the chemical states of the Ti and Al additions hi the BN composite films were examined by X-ray photoelectron spectroscopy (XPS), indicating preferential formation of TiB2 and AlN, respectively. (C) 1999 Elsevier Science S.A. All rights reserved.