CRYSTALLINE FRACTION OF MICROCRYSTALLINE SILICON FILMS PREPARED BY PLASMA-ENHANCED CHEMICAL-VAPOR-DEPOSITION USING PULSED SILANE FLOW

Microcrystalline silicon (muc-Si) films have been prepared at 200-degrees-C by radio-frequency (rf: 13.56 MHz) plasma-enhanced chemical vapor deposition using pulsed silane flow. The crystalline fraction, X(c)(Raman), of muc-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.