Thin-film transistor having a high resistance back channel region am) fabrication method thereof

A thin-film transistor comprising:

• a substrate;
• a layered structure formed on said substrate;
• said layered structure including a semiconductor film having a first subfilm located on one side of said semiconductor film and a second subfilm located on the other side thereof;
• said first subfilm forming an electrically conductive channel of said transistor;
• said second subfilm having a high-resistance part with a high electric resistance, a source contact region connected to one end of said high-resistance part, and a drain contact region connected to the other end of said high-resistance part;
• said high-resistance part being located in a back channel section of said electrically conductive channel and containing an n-type impurity and a p-type impurity;
• a gate insulating film formed to be contacted and overlapped with the first subfilm of said semiconductor film;
• a gate electrode formed to be overlapped with said gate insulating film;
• a source electrode formed to be contacted with and electrically connected to said source contact region of said second subfilm of said semiconductor film and electrically isolated from said high-resistance part, and
• wherein the second subfilm has a thickness in a range between 3 nm and 20 nm.

A thin-film transistor comprising:

• a substrate;
• a layered structure formed on said substrate;
• said layered structure including a semiconductor film having a first subfilm located on one side of said semiconductor film and a second subfilm located on the other side thereof;
• said first subfilm forming an electrically conductive channel of said transistor;
• said second subfilm having a high-resistance part with a high electric resistance, a source contact region connected to one end of said high-resistance part, and a drain contact region connected to the other end of said high-resistance part;
• said high-resistance part being located in a back channel section of said electrically conductive channel and containing an n-type impurity and a p-type impurity;
• a gate insulating film formed to be contacted and overlapped with the first subfilm of said semiconductor film;
• a gate electrode formed to be overlapped with said gate insulating film;
• a source electrode formed to be contacted with and electrically connected to said source contact region of said second subfilm of said semiconductor film;
• a drain electrode formed to be contacted with and electrically connected to said drain contact region of said second subfilm of said semiconductor film,
• wherein said second subfilm has one of an n-type and a p-type conductivity, and further comprising a semiconductor contact layer having an opposite conductivity type from said second subfilm which is disposed in physical contact in a layered relationship with said high resistance part.