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We have observed μc-Si:H films grown in the glass substrate in electron cyclotron resonance plasma-enhanced chemical vapor deposition employing two-step growth (TSG) method, where the seed layer was formed without charged species firstly, and subsequently, the film with charged species. The μc-Si:H films with smooth surface and high crystallinity were synthesized with a relatively high deposition rate at a low substrate temperature by TSG. By Fourier transform infrared attenuated-total reflection, it was found that the surface roughness and crystallinity of seed layer were related to the ratio of SiH bonds over SiH2 ones in the film. Consequently, the control of chemical bonds at the initial layer is of importance and TSG method is effective for the formation of μc-Si:H film with high quality.

Microwave excited plasma source operating at a low pressure of 1.5Pa was newly developed. This plasma source was successfully applied to the formation of hydrogenated microcrystalline silicon films in a glass substrate with a mixture gas of silane (SiH4), hydrogen (H2), and xenon (Xe). It was found that the crystallinity of films was dramatically improved with decreasing pressure. The crystalline fraction was evaluated to be 82% at a substrate temperature of 400°C, a mixture gas of SiH4∕H2∕Xe: 5∕200∕30SCCM, and a total pressure of 1.5Pa by Raman spectroscopy. The absolute density of hydrogen atoms and the behavior of higher radicals and molecules in the mixture gas were evaluated using vacuum ultraviolet absorption spectroscopy and quadrupole mass spectrometer, respectively. H atom densities were of the order of 1011cm−3. The fraction of H atom density increased, while higher radicals and molecules decreased with decrease in the total pressure. The increase in H atom density and decrease in higher radicals and molecules improved the crystallinity of films in low pressures below 10Pa.

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