Fabrication Method for ZnO Thin Film Transistors Using Etch-stop Layer

A method of fabricating a thin film transistor from a plurality of layers deposited on a substrate, the plurality of layers including a conductive gate contact layer, a gate insulator layer, an undoped channel layer, an etch-stop layer, and a conductive contact layer, where the etch-stop layer is positioned between the conductive contact layer and the undoped channel layer, the method comprising:

• selectively removing a portion of the conductive contact layer;
• preventing removal of a portion of the undoped channel layer by the etch-stop layer during the selective removal of the portion of the conductive contact layer;
• selectively removing a portion of the etch-stop layer;
• and
• converting an exposed portion of the etch-stop layer from a conductor to an insulator by oxidizing the exposed portion of the etch-stop layer in air.

A method of fabricating a reduced parasitic capacitance transistor, the method comprising:

• depositing a conductive gate contact layer on a substrate;
• selectively removing a portion of the conductive gate contact layer leaving an etched gate contact layer;
• depositing a plurality of layers on the substrate and the etched gate contact layer, the plurality of layers including a gate insulator layer, an undoped channel layer, an etch-stop layer, and a conductive contact layer, wherein the etch-stop layer is positioned between the conductive contact layer and the undoped channel layer;
• selectively removing a portion of the conductive contact layer;
• preventing removal of a portion of the undoped channel layer by the etch-stop layer during the selective removal of the portion of the conductive contact layer;
• selectively removing a portion of the etch-stop layer;
• converting an exposed portion of the etch-stop layer from a conductor to an insulator by oxidizing the exposed portion of the etch-stop layer in air;
• and
• selectively removing a portion of remaining layers of the plurality of layers to form the transparent thin film transistor.