Microstructure and conductivity of large area nanocrystalline silicon films grown by specially designed thermal-assisted chemical vapor deposition

Abstract

Large-area thin films of silicon consisting of an amorphous matrix with embedded silicon nanocrystallites were deposited on glass substrates using a specially-designed thermal-assisted chemical vapor deposition technique that is compatible with the mature silicon technology. Under this way, the typical nanocrystalline silicon film was grown at 660 °C with crystallization ratio of over 50% and average silicon crystallite size approximately 8–12 nm. The deposition temperature and the post-annealing procedure determine the nanocrystalline Si fraction in the amorphous matrix, which affects the room-temperature dark conductivity of the film. The thermal-assisted tunneling of carriers between neighboring silicon nanocrystallites embedded in amorphous matrix was suggested, which coincides with the theory of hetero-quantum dots.