Method for forming thin film transistor
AssigneeCasio Computer Co., Ltd.
InventorTatsuya Miyakawa
Life of this patent
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Abstract
An amorphous semiconductor layer is deposited on an insulating substrate, and an excimer laser is radiated thereon, and thus the amorphous is crystallized. A silicon oxide layer is deposited on the semiconductor layer, and a silicon nitride layer is deposited on the silicon oxide layer to be thicker than the silicon oxide layer. Thereafter, a gate electrode is formed on the silicon nitride layer. Thus, there is provided a method for a thin film transistor having a good mobility of carriers and a good characteristic of a breakdown voltage in that a gate insulating film is formed of a double-layer structure having the silicon oxide and silicon nitride layers.
Claims9
A method for manufacturing a thin film transistor comprising the steps of:
- forming a polysilicon semiconductor layer having a source region, a drain region, and a channel region, on an insulating substrate;
- directly depositing a two-layer gate insulating film on said polysilicon semiconductor layer, said two-layer gate insulating film having:
- a silicon oxide layer formed on said channel region of said polysilicon semiconductor layer by a sputtering process;
- and
- a silicon nitride layer formed on said silicon oxide layer by a plasma CVD process, said silicon nitride layer having a thickness that is greater than a thickness of said silicon oxide layer;
- and then
- forming a gate electrode on said silicon nitride layer;
- and
- forming a source electrode and a drain electrode on said source region and said drain region of said polysilicon semiconductor layer, respectively.
Dependencies are inferred from the claim text.