Growing cubic boron nitride films at different temperatures

摘要

Cubic boron nitride (cBN) films have been synthesized by both physical and chemical vapor deposition (PVD and CVD) methods at a wide range of substrate temperature. Some works conclude that the cBN growth is insensitive to the temperature parameter while few works suggest that substrate temperature plays a considerable role at cBN deposition, furthermore, the different temperatures used for the nucleation and growth make the situation more complex. In this work, we investigated systematically the growth of cBN films on CVD diamond surfaces at variable temperatures (from 200 to 1100 deg C) using electron cyclotron resonance microwave plasma CVD (ECR-MPCVD) and radio-frequency magnetron sputtering (RF-MS) methods. The role of substrate temperature is discussed in the view of controlling phase purity, crystallinity, growth rate, and residual stress of cBN films deposited. Under optimized conditions, several-micrometers thick films are prepared by ECR-MPCVD as demonstrated on the example of a 3-mu m thick cBN film grown at 900 deg C with faceted surfaces. The sizes of crystallites are fairly large (approx 0.4 mu m) to yield visible Raman spectra characteristic to cBN.