Improvement of the Young's modulus of SiC film by low-pressure chemical vapor deposition with B2H6 gas

SiC is one of the potential materials for use as an x-ray mask substrate. It is preferable for an x-ray mask substrate to have a large elastic modulus, so as to suppress any distortion of the extremely minute and precise patterns. The improvement of the Young's modulus of polycrystalline SIC film using low-pressure chemical vapor deposition with the introduction of B H-2(6) in the source gas was investigated. The Young's modulus increased with the addition of B2H6, and a maximum value of 600 GPa, which was 25% higher than in the cask without B2H6, was reached at a source gas ratio B/Si=0.02. Two models which would possibly explain this phenomenon are discussed, and the theory which takes into account the interaction between carrier and ion core is found to provide a more plausible explanation of the results. (C) 1996 American Institute of Physics.