Method for forming an insulated gate field effect transistor
AssigneeSemiconductor Energy Laboratory Co., Ltd.
InventorsShunpei Yamazaki, Yasuhiko Takemura
Life of this patent
Estimating the term…
Abstract
In an inverted stagger type thin-film transistor, the preparing process thereof can be simplified, and the unevenness of the thin film transistor prepared thereby can be reduced. That is, disclosed is a preparing method which comprises selectively doping a semiconductor on a gate insulating film with an impurity to form source, drain, and channel forming regions, and conducting a laser annealing to them, or a preparing method which comprises selectively doping the semiconductor region with an impurity by a laser doping method.
Claims32
A method of manufacturing a thin film transistor comprising the steps of:
- forming a gate electrode on an insulated surface of a transparent substrate;
- forming a gate insulating film over said gate electrode;
- forming an amorphous semiconductor layer comprising silicon over said gate electrode with said gate insulating film interposed therebetween;
- and
- irradiating portions of the semiconductor layer with a laser light from a rear side of the substrate with a gate electrode as a mask while a surface of the semiconductor layer is exposed to an impurity containing material, thereby simultaneously crystallizing and doping said portions with the impurity,
- wherein a region of the semiconductor layer between said portions is masked by said gate electrode from said laser light so that said region remains amorphous after the irradiation of said laser light.
A method of manufacturing an N-type thin film transistor comprising the steps of:
- forming a gate electrode on an insulated surface of a transparent substrate;
- forming a gate insulating film over said gate electrode;
- forming an amorphous semiconductor layer comprising silicon over said gate electrode with said gate insulating film interposed therebetween;
- and
- irradiating portions of the semiconductor layer with a laser light from a rear side of the substrate with the gate electrode as a mask while a surface of the semiconductor layer is exposed to a donor impurity containing material, thereby simultaneously crystallizing and doping said portions with the impurity,
- wherein a region of the semiconductor layer between said portions is masked by said gate electrode from said laser light so that said region remains amorphous after the irradiation of said laser light.
A method of manufacturing a thin film transistor comprising the steps of:
- forming a gate electrode on an insulated surface of a transparent substrate;
- forming a gate insulating film comprising silicon nitride over said gate electrode;
- forming an amorphous semiconductor layer comprising silicon over said gate electrode with said gate insulating film interposed therebetween;
- and
- irradiating portions of the semiconductor layer with a laser light from a rear side of the substrate with the gate electrode as a mask while a surface of the semiconductor layer is exposed to an impurity containing material, thereby simultaneously crystallizing and doping said portions with the impurity,
- wherein a region of the semiconductor layer between said portions is masked by said gate electrode from said laser light so that said region remains amorphous after the irradiation of said laser light.
A method of manufacturing a thin film transistor comprising the steps of:
- forming a gate electrode on an insulated surface of a transparent substrate;
- forming a gate insulating film over said gate electrode;
- forming an amorphous semiconductor layer comprising silicon over said gate electrode with said gate insulating film interposed therebetween, said semiconductor layer having a thickness not larger than 100 nm;
- and
- irradiating portions of the semiconductor layer with a laser light from a rear side of the substrate with the gate electrode as a mask while a surface of the semiconductor layer is exposed to an impurity containing material, thereby simultaneously crystallizing and doping said portions with the impurity,
- wherein a region of the semiconductor layer between said portions is masked by said gate electrode from said laser light so that said region remains amorphous after the irradiation of said laser light.
Dependencies are inferred from the claim text.