Contamination of an interface of respective films constituting a TFT due to an contaminant impurity in a clean room atmosphere becomes a great factor to lower the reliability of the TFT. Besides, when an impurity is added to a crystalline semiconductor film, its crystal structure is broken. By using...http://www.google.ca/patents/US7169689?utm_source=gb-gplus-sharePatent US7169689 - Method of manufacturing a semiconductor device
