A semiconductor device using a TFT structure with high reliability is realized.
As an insulating film used for the TFT, for example, a gate insulating film, a
protecting film, an under film, an interlayer insulating film, or the like, a silicon
nitride oxide film (SiNXBYOz) containing boron
is formed by a sputtering method. As a result, the internal stress of this film
becomes -51010 dyn/cm2 to 51010 dyn/cm2,
preferably -1010 dyn/cm2 to 1010 dyn/cm2,
and the film has high thermal conductivity, so that it typically becomes possible
to prevent deterioration due to heat generated at the time of an on operation of
the TFT.
