Preparation and Mechanical Characterization of Amorphous B-C Films

Abstract

This study has demonstrated that trimethylboron, B(CH3)3 is a suitable boron source material for the fabrication amorphous boron carbide (a-BC:H) films. a-BC:H films were deposited by pluse plasma chemical vapor deposition on a silicon substrate (100) with different gas pressures and gas flow rates at constant voltage, -5 kV . The grown a-BC:H films were found to be porous surface and their thickness were in the range of 0.95 to 1.56 μm for 3 h of deposition time. Results indicated that the boron contents, morphologies and mechanical properties of the a-BC:H films were dependent on the gas pressures and gas flow rate. The increased of boron content will introduce more porous film surface. The effect of boron content on the mechanical properties such as hardness, Youngs modulus, and wear resistance were discussed. The good quality film is obtained from B(CH3)3 at 5 Pa and gas flow rate of 15 cm3/min which boron to carbon atomic ratio is 0.43. This film has lower friction coefficient (0.3) sliding against stainless steel ball, high hardness (8.1 GPa) and Youngs modulus (62.2 GPa).