Method of manufacturing a semiconductor device

A method of manufacturing a semiconductor device, comprising the steps of:

• forming a semiconductor layer on a plastic substrate;
• forming a gate insulating film on the semiconductor layer;
• and
• forming a conductive layer on the gate insulating film,
• wherein the step of forming the gate insulating film is performed by a sputtering method using one of silicon and silicon oxide as a target and has a first stage for forming a first insulating film including mainly silicon, oxygen, and nitrogen and further including hydrogen at a concentration of 0.4 atomic % to 1.6 atomic % and a second stage for forming a second insulating film including mainly silicon and oxygen and further including hydrogen at a concentration of 0.2 atomic % or lower.

A method of manufacturing a semiconductor device, comprising the steps of:

• forming a semiconductor layer on an insulating surface;
• forming a first insulating film comprising silicon, oxygen, and nitrogen on the semiconductor layer by a sputtering method, said fist insulating film further including hydrogen;
• forming a second insulating film comprising silicon, and oxygen by the sputtering method, said second insulating film further including hydrogen at a lower concentration than that of the first insulating film;
• and
• forming a conductive layer on the first and second insulating films.

A semiconductor device comprising:

• a semiconductor layer on an insulating surface;
• a first insulating film comprising silicon, oxygen, and nitrogen on the semiconductor layer, said fist insulating film further including hydrogen;
• a second insulating film comprising silicon, and oxygen, said second insulating film further including hydrogen at a lower concentration than that of the first insulating film;
• and
• a conductive layer on the first and second insulating films.