Nanostructural and Chemical Arrangement of BCN Gradient Thin Films

Gradient films of ternary BCN phases on a Si(100) substrate are prepared for the first time by plasma-enhanced chemical vapor deposition using trimethylamine borane complex and ammonia. The gradient character of films is provided by a stepwise ammonia content decrease at a constant synthesis temperature or by a stepwise temperature decrease at the constant initial composition of the gas phase. The reliability of the interpretation of experimental data obtained for the gradient films is verified using a specially prepared series of reference BCN films. Structural and chemical features of the reference and thickness-gradient films are studied by FTIR and Raman spectroscopy, HRTEM, SAED, and SEM/EDX. Several interesting nanostructures formed with different sequences and thickness are determined for both gradient films. The textural relationships between amorphous and nanocrystalline components of these films as well as chemical compositions of the latter are discussed in detail.