The influence of hydrogen on nucleation and growth of cubic boron nitride films

The presence of hydrogen in the gas phase of (ion-assisted) CVD processes is detrimental to the formation of cubic boron nitride (c-BN). By elastic recoil detection measurements it is shown that this is caused by the incorporation of hydrogen, especially into the h-BN nucleation layer, thus causing a degradation of this nucleation layer as well as the subsequent c-BN layer. Experiments carried out to solve this hydrogen problem revealed that the hydrogen content of CVD c-BN films can be reduced by either the use of precursors in which hydrogen is (partially) replaced by halogenes, or the use of high substrate temperatures. The reduced hydrogen content reflects in the nucleation behaviour of c-BN films as well as in their properties.