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 microstructure of boron nitride thin films grown on silicon (100) by radio-frequency plasma-assisted chemical vapor deposition using B2H6 (1% in H-2) and NH3 gases. Well-adhered boron nitride films grown on the grounded electrode show a highly oriented hexagonal structure with the c-axis parallel to the substrate surface throughout the film, without any interfacial amorphous layer. We ascribed this textured growth to an etching effect of atomic hydrogen present in the gas discharge. In contrast, films grown on the powered electrode, with compressive stress induced by ion bombardment, show a multilayered structure as observed by other authors, composed of an amorphous layer, a hexagonal layer with the c-axis parallel to the substrate surface and another layer oriented at random. (C) 1996 American Institute of Physics.