Chemical vapor deposition of boron carbide

Abstract

Boron carbide is an important non-metallic material with outstanding hardness, excellent mechanical, thermal and electrical properties. Its low density, high chemical inertness and neutron capture section make boron carbide an attractive material for micro-electronic, nuclear, military, space and medical applications. Boron carbide based materials are widely deposited by chemical vapor deposition methods (CVD). This paper provides a comprehensive review on the recent literature of boron carbide CVD. Structure, properties and potential application areas of this material are also reviewed. The status of the theoretical modeling of boron carbide deposition and the developments on the experimental processes are reported. It was evident from this review that extensive research still remains to be done on the modeling of CVD boron carbides. Majority of the reviewed published research papers deals with characterization, and growth rate of deposited boron carbide phases. Some thermodynamic modeling based on Gibbs free energy minimization were attempted in classical CVD systems. However, these models were often not able to represent the actual growth mechanism. No significant modeling work has been reported in other CVD systems such as plasma enhanced chemical vapor deposition (PECVD), hot filament chemical vapor deposition (HFCVD), synchrotron radiation chemical vapor deposition (SRCVD). Reliable thermo-chemical data for boron carbides with various stoichiometries are also needed to study and model actual deposition reaction mechanisms of such complex systems.