Nucleation of c-BN from PECVD and TACVD growth species: A theoretical study

The nucleation of cubic boron nitride (c-BN) on the zigzag edges (100) and ((1) over bar 00) of the hexagonal BN (h-BN) prism plane has been theoretic ally investigated, using a cluster approach and the density functional theo ry (DFT). Different cubic outgrowths from the edge atoms have been modeled, and the total energies have been set in relation to the total energies for corresponding hexagonal counterparts. The outgrowths were assumed to be de rived from the gaseous complexes X2BNH2 and XB(NH2)(2) (X = Cl or H), exper imentally observed in TACVD and PECVD reactors. It was found that the nucle ation of cubic BN is energetically favorable compared to a continuous growt h of hexagonal BN on the two edges investigated. The order of relative ener gy obtained for the various edges considered is; ((1) over bar 00) > (100). Moreover, the Cl atoms showed the highest ability to stabilize the cubic n uclei, with one exception. However, the energetic differences between the t wo terminating species were rather small. (C) 2001 Elsevier Science B.V. Ah rights reserved.