Microstructure and mechanical properties of boron carbide thin films

Boron carbide thin films were deposited on single-crystal silicon substrates with magnetron sputtering method at different temperatures using a sintered B4C target. Auger electron spectroscopy, Fourier transform infrared spectroscopy and transmission electronic microscopy were employed to characterize their chemical compositions and microstructure. Mechanical properties of the films were evaluated using a nanoindenter. The results show the as-deposited boron carbide films are amorphous or microcrystalline with high hardness and high modulus. With the increase of the substrate temperature, boron carbide films show a tendency of crystallization, and accordingly the hardness and modulus reach 50.4 and 420 GPa from 42.5 and 300 GPa, respectively. (C) 2002 Elsevier Science B.V. All rights reserved.