High rate growth of microcrystalline silicon using a high-pressure depletion method with VHF plasma

The deposition of hydrogenated microcrystalline Si (μc-Si) at working pressure from 0.5 to 4 Torr was performed using a very-high-frequency (VHF) plasma-enhanced chemical vapor deposition (PECVD) method. Correlation of the growth rate and grain size with deposition parameters such as working pressure, silane flow rate, excitation frequency and input power were investigated. With increasing silane flow rate from 10 to 50 sccm, the growth rate increased from 13 to 28 Å/s keeping grain size at 300 Å. It was also found that the growth rate strongly depended on configuration of gas injection. μc-Si film with the growth rate of 50 Å/s at 250°C was obtained by injecting the silane gas from near the cathode at an excitation frequency of 60 MHz.