EFFECT OF STOICHIOMETRY ON THE PHASES PRESENT IN BORON-NITRIDE THIN-FILMS

Boron nitride thin films were deposited by ion-assisted evaporation an d characterized by neutron depth profiling (NDP), a nondestructive met hod for the compositional analysis of solids. The phases present in th e films were determined by infrared spectroscopy. Examination of the d ata presented here and comparison with the work of other authors revea led that stoichiometric or nearly stoichiometric films contained the g reatest amount of the cubic phase. This led to the proposition that fi lm stoichiometry is one of the factors that stabilize cubic boron nitr ide in boron nitride thin films. A shift in the position of the cubic boron nitride infrared absorption was also observed by the present aut hors which was related to film stoichiometry. Discussion of the variou s techniques commonly used to determine the stoichiometry of boron nit ride thin films emphasized the need for all stoichiometry measurements to be made using the same characterization method in order for all re sults to be compared with confidence. The advantages of NDP, such as i ts high accuracy and depth profiling capability, make it a suitable ca ndidate for this application.