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US 2014/0273342 A1Published application
Vth control method of multiple active layer metal oxide semiconductor tft
AssigneeApplied Materials, Inc.
InventorsDong-Kil YIM, Rodney Shunleong LIM, Evelyn SCHEER, Tae Kyung WON, Soo Young CHOI, Harvey YOU
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Abstract
The present invention generally relates to TFTs and methods for fabricating TFTs. When multiple layers are used for the semiconductor material in a TFT, a negative Vth shift may result. By exposing the semiconductor layer to an oxygen containing plasma and/or forming an etch stop layer thereover, the negative Vth shift may be negated.
Claims20
A method of fabricating a thin film transistor, comprising:
- depositing a semiconductor layer over a substrate having a gate electrode and gate dielectric layer disposed thereon;
- exposing the semiconductor layer to an oxygen containing plasma;
- depositing an etch stop layer over the semiconductor layer;
- and
- forming source and drain electrodes over the etch stop layer.
2 more elements
A method of fabricating a thin film transistor, comprising:
- depositing a semiconductor layer over a substrate having a gate electrode and gate dielectric layer disposed thereon;
- depositing an etch stop layer over the semiconductor layer by a PECVD process comprising maintaining the substrate at a temperature of less than about 250 degrees Celsius, delivering an oxygen containing gas and a silicon containing gas in a ratio of oxygen containing gas to silicon containing gas of greater than 30:1, maintaining a chamber pressure of greater than about 1.25 Torr and delivering an RF power density of less than 3.34 kW/m2;
- and
- forming source and drain electrodes over the etch stop layer.
1 more element
A method of fabricating a back channel etch thin film transistor, comprising:
- depositing a semiconductor layer over a substrate having a gate electrode and gate dielectric layer disposed thereon;
- exposing the semiconductor layer to an oxygen containing plasma, wherein the exposing comprises forming a plasma from an oxygen containing gas selected from the group consisting of O2, N2O, O3 and combinations thereof, wherein the exposing occurs at a pressure of less than 3 Torr, and wherein the plasma is ignited with an RF power density of greater than about 0.83 kW/m2;
- forming source and drain electrodes over the semiconductor layer;
- and
- depositing a passivation layer over the semiconductor layer and the source and drain electrodes.
2 more elements
Dependencies are inferred from the claim text.