Insulated gate field effect transistor and its manufacturing method

A thin film transistor comprising:

• a semiconductor layer comprising a non-single crystalline semiconductor layer formed on an insulating surface of a substrate;
• a gate electrode formed on said semiconductor layer;
• a gate insulating film disposed between said gate electrode and said semiconductor layer;
• a source region and a draining region formed in said semiconductor layer;
• a channel region extending between said source and drain regions in said semiconductor layer, where said source and drain regions have a different conductivity type from said channel region;
• and
• an interlayer insulating film covering at least said gate electrode and semiconductor layer except for a contact hole of at least one of said source and drain regions where said contact hole is disposed partially over said at least one of said source and draining regions;
• wherein at least one of said source region and said drain region is provided with an electrode through said contact hole of the interlayer insulating layer, said electrode being contacted with an upper surface and a side edge surface of one of said source region and said drain region.

A thin film transistor comprising:

• a non-single crystalline semiconductor layer formed on an insulating surface of a substrate;
• a gate electrode formed on said semiconductor layer;
• a gate insulating film disposed between said gate electrode and said semiconductor layer;
• a source region and a drain region contacting said semiconductor layer;
• a channel region existing in said semiconductor layer where said source and drain regions have ends which are removed from said channel region;
• and
• an interlayer insulating film covering at least said gate electrode and semiconductor layer except for a contact hole which extends beyond the said end of at least one of said source and drain regions where said contact hole is disposed partially over said at least one of said source and drain regions;
• wherein at least one of said source region and said drain region is provided with an electrode through said contact hole, said electrode being contacted with at least an upper surface of one of said source region and said draining region.