Method for manufacturing a thin film transistor
OwnerChia-Tien Peng, Ta-Shun Lininventors
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Abstract
The present invention concerns a method for manufacturing a thin film transistor on a substrate. An amorphous silicon film is deposited on the substrate. A plasma treatment is used to adjust threshold voltage (Vt) of the thin film transistor instead of conventional ion implantation Vt adjustment. A crystallizationtreatment is carried out to transform the amorphous silicon film into a polysilicon layer. According toa preferred embodiment of the present invention, to create a negative shift of the threshold voltage of the thin film transistor, oxygen-containing plasma is used at a RF power lower than 500W. To create a positive shift of the threshold voltage of the thin film transistor, ammonia plasma is used.
Claims17
A method for manufacturing a thin film transistor, comprising the steps of:
- providing a substrate;
- depositing an amorphous silicon layer over the substrate;
- generating a plasma contacting with the amorphous silicon layer for adjusting threshold voltage of the thin film transistor;
- and
- performing a crystallization process to transform the amorphous silicon layer into a polysilicon layer.
A method for fabricating a low temperature polysilicon thin film transistor (LTPS TFT), comprising the steps of:
- providing a transparent substrate;
- depositing at least one buffer layer on the substrate performing a chemical vapor deposition (CVD) process to deposit an amorphous silicon layer on the buffer layer, wherein the CVD process is carried out in a CVD vacuum chamber;
- in-situ adjusting threshold voltage of the LTPS TFT by contacting the amorphous silicon layer with plasma generated within the CVD vacuum chamber;
- and
- performing a crystallization process to transform the amorphous silicon layer into a polysilicon layer.
Dependencies are inferred from the claim text.