Dual gate control for trench shaped thin film transistors

A method of fabricating a thin film transistor structure, comprising:

• forming a trench extending through a metal layer, a first semiconductor layer, and a dielectric layer to expose a surface of a first gate dielectric layer, wherein the first gate dielectric layer is over a first gate electrode;
• growing a second semiconductor layer from the first semiconductor layer and over the dielectric layer and the surface of the first gate dielectric layer to form a non-planar semiconductor layer having a portion over the surface of the first gate dielectric layer;
• disposing a second gate dielectric layer over the portion of the non-planar semiconductor layer;
• and
• disposing a second gate electrode at least partially within the trench, wherein the second gate dielectric layer is between the portion of the non-planar semiconductor layer and the second gate electrode.

A method of fabricating a thin film transistor structure comprising:

• forming a trench extending through a source and drain material layer, a first thin film semiconductor layer, and a dielectric layer to expose a surface of a first gate dielectric layer, wherein the first gate dielectric layer is over a first gate electrode structure;
• growing a second thin film semiconductor layer from the first thin film semiconductor layer and over the dielectric layer and the surface of the first gate dielectric layer to form a non-planar thin film semiconductor layer having a portion over the surface of the first gate dielectric layer;
• disposing a second gate dielectric layer over the portion of the non-planar thin film semiconductor layer;
• and
• disposing a second gate electrode structure at least partially within the trench, wherein the second gate dielectric layer is between the portion of the non-planar thin film semiconductor layer and the second gate electrode structure.