Semiconductor device having a crystallized silicon thin film in which the crystallization direction is oriented either vertically or horizontally to the current flow direction
AssigneeSemiconductor Energy Laboratory Co., Ltd.
InventorYasuhiko Takemura
Life of this patent
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Abstract
A silicon film is crystallized in a predetermined direction by selectively adding a metal element having a catalytic action for crystallizing an amorphous silicon and annealing. In manufacturing TFT using the crystallized silicon film, TFT provided such that the crystallization direction is roughly parallel to a current-flow between a source and a drain, and TFT provided such that the crystallization direction is roughly vertical to a current-flow between a source and a drain are manufactured. Therefore, TFT capable of conducting a high speed operation and TFT having a low leak current are formed on the same substrate.
Claims18
A method for manufacturing a semiconductor device comprising the steps of:
- forming a silicon film having an amorphous on a substrate;
- preparing an element which promotes crystallization before or after formation of the silicon film, to introduce the element into a region of the silicon film;
- crystallizing the silicon film, wherein the silicon film is crystal-grown from the region in a crystal growth direction parallel to the substrate;
- oxidizing the silicon film, to form a silicon oxide layer on the silicon film;
- and
- forming a plurality of thin film transistors using the silicon film,
- wherein at least one of the thin film transistors has a first angle formed between a carrier moving direction and the crystal growth direction and at least another one of the thin film transistors has a second angle which is different from the first angle and formed between the carrier moving direction and the crystal growth direction.
The method of claim 8 wherein the first angle is approximately 0.degree. and the second angle is approximately 90.degree..
A method for manufacturing a semiconductor device for an active matrix type liquid crystal display having a peripheral circuit portion and a pixel portion, comprising the steps of:
- forming a silicon film having an amorphous on a substrate;
- preparing an element which promotes crystallization before or after formation of the silicon film, to introduce the element into a region of the silicon film;
- crystallizing the silicon film, wherein the silicon film is crystal-grown from the region in a crystal growth direction parallel to the substrate;
- oxidizing the silicon film, to form a silicon oxide film on the silicon film;
- and
- forming a plurality of thin film transistors using the oxidized silicon film,
- wherein at least one of the thin film transistors is provided as the peripheral circuit portion and has a first angle formed between a carrier moving direction and the crystal growth direction, and at least another one of the thin film transistors is provided as the pixel portion and has a second angle which is different from the first angle and formed between the carrier moving direction and the crystal growth direction.
A method for manufacturing a semiconductor device comprising the steps of:
- forming a silicon film having an amorphous on a substrate;
- preparing an element which promotes crystallization before or after formation of the silicon film, to introduce the element into a region of the silicon film;
- crystallizing the silicon film, wherein the silicon film is crystal-grown from the region in a crystal growth direction;
- oxidizing the silicon film, to form a silicon oxide layer on the silicon film;
- and
- forming a plurality of thin film transistors using the silicon film,
- wherein at least one of the thin film transistors has the silicon film crystal-grown in the crystal growth direction which coincides with a carrier moving direction and at least another one of the thin film transistors has the silicon film crystal-grown in the crystal growth direction which is different from the carrier moving direction.
A method for manufacturing a semiconductor device comprising the steps of:
- forming a silicon film having an amorphous on a substrate;
- preparing an element which promotes crystallization before or after formation of the silicon film, to introduce the element into a region of the silicon film;
- crystallizing the silicon film, wherein the silicon film is crystal-grown from the region in a crystal growth direction parallel to the substrate to obtain a crystal growth region;
- oxidizing the silicon film, to form a silicon oxide layer on the silicon film;
- and
- forming a plurality of thin film transistors using the silicon film,
- wherein at least one of the thin film transistors has a first angle formed between a carrier moving direction and the crystal growth direction and at least another one of the thin film transistors has a second angle which is different from the first angle and formed between the carrier moving direction and the crystal growth direction, and
- wherein the crystal growth region includes the element and a concentration of the element included in the crystal growth region is 1.times.10.sup.17 to 1.times.10.sup.20 atoms/cm.sup.3.
A method for manufacturing a semiconductor device for an active matrix type liquid crystal display having a peripheral circuit portion and a pixel portion, comprising the steps of:
- forming a silicon film having an amorphous on a substrate;
- preparing an element which promotes crystallization before or after formation of the silicon film, to introduce the element into a region of the silicon film;
- crystallizing the silicon film, wherein the silicon film is crystal-grown from the region in a crystal growth direction;
- oxidizing the silicon film, to form a silicon oxide layer on the silicon film;
- and
- forming a plurality of thin film transistors using the silicon film,
- wherein at least one of the thin film transistors has the silicon film crystal-grown in the crystal growth direction which coincides with a carrier moving direction and at least another one of the thin film transistors has the silicon film crystal-grown in the crystal growth direction which is different from the carrier moving direction.
A method for manufacturing a semiconductor device comprising the steps of:
- forming a silicon film having an amorphous on a substrate;
- preparing nickel before or after formation of the silicon film, to introduce the nickel into a region of the silicon film;
- crystallizing the silicon film, wherein the silicon film is crystal-grown from the region in a crystal growth direction parallel to the substrate to obtain a crystal growth region;
- oxidizing the silicon film, to form a silicon oxide layer on the silicon film;
- and
- forming a plurality of thin film transistors using the silicon film,
- wherein at least one of the thin film transistors has a first angle formed between a carrier moving direction and the crystal growth direction and at least another one of the thin film transistors has a second angle which is different from the first angle and formed between the carrier moving direction and the crystal growth direction.
Dependencies are inferred from the claim text.