Effects of Plasma-Substrate Distance on Properties of Hydrogenated Amorphous Silicon Deposited from Hydrogen-Diluted Silane

Abstract
Hydrogenated amorphous silicon (a-Si:H) was prepared on substrates located away from rf plasma of hydrogen-diluted silane at 3 Torr. Physical and chemical structures of the films were changed by altering the distance between the plasma and the substrates. An optimum separation distance between the plasma and the substrates was found. The effects of substrate temperature and hydrogen dilution on film properties were also examined. The changes in film properties were explained by taking into account three types of film precursors: favorable radicals of lower sticking probability, unfavorable sticky ones and unfavorable polymerized ones.