Thin film transistor including a compositionally-graded gate dielectric and methods for forming the same
AssigneeTaiwan Semiconductor Manufacturing Company, Ltd.
InventorsWu-Wei Tsai, Chun-Chieh Lu, Hai-Ching Chen, Yu-Ming Lin, Sai-Hooi Yeong
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Abstract
A thin film transistor may be manufactured by forming a gate electrode in an insulating layer over a substrate, forming a gate dielectric over the gate electrode and the insulating layer, forming an active layer over the gate electrode, and forming a source electrode and a drain electrode contacting a respective portion of a top surface of the active layer. A surface oxygen concentration may be increased in at least one of the gate dielectric and the active layer by introducing oxygen atoms into a surface region of a respective one of the gate dielectric and the active layer.
Claims20
A semiconductor device comprising a thin film transistor located over a substrate, wherein the thin film transistor comprises:
- an insulating layer embedding a gate electrode and overlying a substrate;
- a stack of a gate dielectric and an active layer comprising a semiconducting metal oxide material;
- a source electrode in direct contact with a first end segment of a top surface of the active layer, a first surface segment of a top surface of the insulating layer, and an entirety of a first one of a pair of widthwise sidewalls of the active layer;
- and
- a top gate dielectric contacting a portion of the top surface of the active layer, portions of a pair of lengthwise sidewalls of the active layer, an additional segment of the top surface of the insulating layer, and a segment of a top surface of the gate electrode that does not overlap with the active layer in a plan view along a vertical direction,
- wherein a pair of sidewalls of the top gate dielectric extends along a direction that is perpendicular to a separation direction between the source electrode and a drain electrode from the segment of the top surface of the gate electrode to the additional segment of the top surface of the insulating layer.
A semiconductor device comprising a thin film transistor located over a substrate, wherein the thin film transistor comprises:
- a gate electrode overlying a substrate;
- a stack of a gate dielectric and an active layer comprising a semiconducting metal oxide material, the stack overlying the gate electrode;
- a source electrode and a drain electrode contacting a respective portion of a top surface of the active layer;
- a top gate dielectric contacting a portion of a top surface of the active layer, portions of a pair of lengthwise sidewalls of the active layer, a segment of a top surface of an insulating layer that embeds the gate electrode, and a segment of a top surface of the gate electrode that does not overlap with the active layer in a plan view along a vertical direction;
- and
- a top gate electrode overlying the top gate dielectric.
A semiconductor device comprising a thin film transistor located over a substrate, wherein the thin film transistor comprises:
- an insulating layer embedding a gate electrode and overlying a substrate;
- a stack of a gate dielectric and an active layer comprising a semiconducting metal oxide material;
- a dielectric layer overlying the insulating layer and laterally surrounding the stack;
- a top gate dielectric contacting a portion of a top surface of the active layer, portions of the pair of lengthwise sidewalls of the active layer, a segment of a top surface of the insulating layer, and a segment of a top surface of the gate electrode that does not overlap with the active layer, in a plan view along a vertical direction;
- and
- a top gate electrode overlying the top gate dielectric.
Dependencies are inferred from the claim text.