Deposition of low stress, high transmittance SiC as an x-ray mask membraneusing ECR plasma CVD

SIC for x-ray mask membrane is deposited by Electron Cyclotron Resonance pl asma Chemical Vapor Deposition from SiH4/CH4/Ar mixtures. Stoichiometric Si C is deposited at SiH4/CH4 ratio of 0.4, deposition temperature of 600 degr ees C and microwave power of 500 W with +/-5 % thickness uniformity. As-dep osited film has compressive residual stress, very smooth surface (31 Angstr om rms) and high optical transmittance of 90 % at 633 nm wavelength. The mi crostructure of this film consists of the nanocrystalline particle (100 Ang strom similar to 200 Angstrom) embedded in amorphous matrix. Residual stres s can be tuned to tensile stress via Rapid Thermal Annealing in N-2 atmosph ere, while suppressing structural change during annealing. As a result, smo oth (37 Angstrom rms) SiC film with moderate tensile stress and high optica l transmittance (85 % at 633 nm wavelength) is obtained.