Thin film transistors

A thin-film transistor, comprising:

• a substrate;
• a gate electrode disposed on the substrate;
• a gate dielectric disposed on the gate electrode;
• a channel layer having a first surface and an opposed second surface, the first surface being disposed over at least a portion of the gate dielectric, the channel layer having a first oxide composition including at least one cation selected from zinc, tin, indium, and gallium;
• at least one drain in electrical contact with the channel layer;
• at least one source electrode in electrical contact with the channel layer;
• a passivation layer disposed adjacent to at least a portion of the second opposed surface of the channel layer, the passivation layer having a second oxide composition including the at least one cation of the first oxide composition and at least one additional cation selected from aluminum, boron, hafnium, magnesium, niobium, silicon, tantalum, yttrium, and zirconium;
• and
• a second passivation layer disposed adjacent to the passivation layer, the second passivation layer being selected from aluminum oxide, hafnium oxide, silicon nitride, silicon oxide, silicon oxynitride, and zirconium oxide.

A method of forming a structure, comprising:

• selecting a first oxide composition including at least one predetermined cation, and second oxide composition including the at least one predetermined cation of the first oxide composition and at least one additional cation that increases a bandgap of the second oxide composition relative to the first oxide composition;
• depositing the first oxide composition over at least a portion of a gate dielectric to form a channel layer;
• and
• passivating an exposed portion of the channel layer with the second oxide composition to form a passivation layer.