Cluster-suppressed plasma chemical vapor deposition method for high quality hydrogenated amorphous silicon films

We have developed a novel plasma chemical vapor deposition (PCVD) method for preparing high quality hydrogenated amorphous silicon (a-Si:H) films, which suppresses effectively growth of clusters by transporting them out of the reactor using gas flow and thermophoresis. By utilizing this cluster-suppressed PCVD method, we have demonstrated deposition of quite high quality a-Si:H films, microstructure parameter R-alpha of which can be reduced below 0.003. The decrease in Ralpha value is closely related to the decrease in cluster amount. Preliminary evaluation of fill factor (FF) of the a-Si:H Schottky solar cell of the a-Si:H films of R-alpha = 0.057 shows the high initial value FFi = 0.57 and high stabilized value after-light-soaking FFa = 0.53.