Wettability of Silicon Oxide with Poly-Crystalline Silicon

Stoichiometric change of underlying silicon oxide has been found to have a great influence upon the properties of thin poly-crystalline silicon (poly-Si) films deposited on an underlying silicon oxide, resulting in important characteristics changes of the poly-Si thin film transistors (TFTs) made on it. The silicon oxide containing excessive silicon atoms has fairly good wettability with silicon so that the thin poly-Si deposited on it is in a continuous film state even if it is as thin as 25 nm and is deposited under infra-low pressure. The thin poly-Si on the stoichiometricaly perfect silicon dioxide, on the other hand, is in a separate island-like state but consists of large crystallites. The best TFTs will be fabricated by optimizing the amount of silicon content in the underlying silicon oxide, the poly-Si deposition condition, and the thickness of poly-Si film.