MICROSTRUCTURE OF HIGHLY ORIENTED, HEXAGONAL, BORON-NITRIDE THIN-FILMS GROWN ON CRYSTALLINE SILICON BY RADIO-FREQUENCY PLASMA-ASSISTED CHEMICAL-VAPOR-DEPOSITION

We present a high-resolution electron microscopy study of the microstr ucture of boron nitride thin films grown on silicon (100) by radio-fre quency plasma-assisted chemical vapor deposition using B2H6 (1% in H-2 ) and NH3 gases. Well-adhered boron nitride films grown on the grounde d electrode show a highly oriented hexagonal structure with the c-axis parallel to the substrate surface throughout the film, without any in terfacial amorphous layer. We ascribed this textured growth to an etch ing effect of atomic hydrogen present in the gas discharge. In contras t, films grown on the powered electrode, with compressive stress induc ed by ion bombardment, show a multilayered structure as observed by ot her authors, composed of an amorphous layer, a hexagonal layer with th e c-axis parallel to the substrate surface and another layer oriented at random. (C) 1996 American Institute of Physics.