Thin film transistors and arrays with controllable threshold voltages and off state leakage current

A thin film transistor with controllable threshold voltage and OFF state leakage current comprising:

• a substrate,
• a first gate electrode,
• a first gate insulator layer containing a first fixed insulator charges with a controlled first fixed insulator charge density,
• a drain,
• a source;
• and
• a first active channel,
• wherein said first fixed insulator charges are negative for a n-channel transistor and positive for a p-channel transistor.

A thin film transistor array with controllable threshold voltage and OFF state leakage current comprising:

• a plurality of thin film transistors, each thin film transistor of said array having
• a substrate,
• a first gate electrode,
• a first gate insulator layer containing first fixed insulator charges with a first fixed insulator charge density,
• a second gate insulator layer containing second fixed insulator charges with a second fixed insulator charge density,
• a drain,
• a source,
• a first active channel, and
• wherein said first fixed insulator charges and said second fixed insulator charges have opposite signs, said first fixed insulator charge density and said second fixed insulator charge density are controlled during fabrication so that said first gate insulator layer and said second gate insulator layer forming an double layer gate insulator with a net charge density substantially smaller than said first fixed insulator charge density and said second fixed insulator charge density.