Crystalline Fraction of Microcrystalline Silicon Films Prepared by Plasma-Enhanced Chemical Vapor Deposition Using Pulsed Silane Flow

Microcrystalline silicon (?c-Si) films have been prepared at 200?C by radio-frequency (rf: 13.56 MHz) plasma-enhanced chemical vapor deposition using pulsed silane flow. The crystalline fraction, X c (Raman), of ?c-Si films approximately 200 nm thick is quantitatively determined by decomposing Raman spectra into three peaks: crystalline, intermediate (small-grain-size-crystalline), and amorphous. The effects of rf power on X c (Raman) and hydrogen content, C H , have been studied. X c (Raman) increases with increasing rf power and tends to saturate; the maximum value of X c (Raman) is 71%. With increasing rf power C H decreases to a minimum value of 4.5% and then increases. Hydrogen introduction into Si films overlapped with hydrogen elimination is responsible for the increase and saturation of X c (Raman) with rf power.