Method for manufacturing semiconductor device
First Claim
1. A method for manufacturing a semiconductor device comprising the steps of:
- forming an oxide semiconductor layer;
performing a first heat treatment on the oxide semiconductor layer to reduce a hydrogen concentration of the oxide semiconductor layer in an inert atmosphere in a chamber;
after the first heat treatment, introducing oxygen into the chamber in order to supply oxygen to the oxide semiconductor layer in the chamber; and
forming an oxide insulating film in contact with the oxide semiconductor layer.
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Abstract
An object is to manufacture a highly reliable semiconductor device including a thin film transistor with stable electric characteristics. In a method for manufacturing a semiconductor device including a thin film transistor in which an oxide semiconductor film is used for a semiconductor layer including a channel formation region, heat treatment (for dehydration or dehydrogenation) is performed to improve the purity of the oxide semiconductor film and reduce impurities including moisture or the like. After that, slow cooling is performed under an oxygen atmosphere. Besides impurities including moisture or the like exiting in the oxide semiconductor film, heat treatment causes reduction of impurities including moisture or the like exiting in a gate insulating layer and those in interfaces between the oxide semiconductor film and films which are provided over and below the oxide semiconductor and in contact therewith.
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Citations
31 Claims
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1. A method for manufacturing a semiconductor device comprising the steps of:
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forming an oxide semiconductor layer; performing a first heat treatment on the oxide semiconductor layer to reduce a hydrogen concentration of the oxide semiconductor layer in an inert atmosphere in a chamber; after the first heat treatment, introducing oxygen into the chamber in order to supply oxygen to the oxide semiconductor layer in the chamber; and forming an oxide insulating film in contact with the oxide semiconductor layer. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method for manufacturing a semiconductor device comprising the steps of:
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forming an oxide semiconductor layer; performing a first heat treatment on the oxide semiconductor layer to reduce a hydrogen concentration of the oxide semiconductor layer under reduced pressure in a chamber; after the first heat treatment, introducing oxygen into the chamber in order to supply oxygen to the oxide semiconductor layer in the chamber; and forming an oxide insulating film in contact with the oxide semiconductor layer. - View Dependent Claims (9, 10, 11, 12, 13)
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14. A method for manufacturing a semiconductor device comprising the steps of:
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forming a gate electrode over a substrate; forming a gate insulating layer over the gate electrode; forming an oxide semiconductor layer over the gate insulating layer; performing a first heat treatment on the oxide semiconductor layer in a chamber; after the first heat treatment, introducing oxygen into the chamber in order to supply oxygen to the oxide semiconductor layer in the chamber; forming a source electrode and a drain electrode over the oxide semiconductor layer; and forming an oxide insulating film in contact with the oxide semiconductor layer, wherein the first heat treatment is performed at a first temperature higher or equal to 400°
C. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22)
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23. A method for manufacturing a semiconductor device comprising the steps of:
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forming a gate electrode over a substrate; forming a gate insulating layer over the gate electrode; forming an oxide semiconductor layer over the gate insulating layer; performing a first heat treatment on the oxide semiconductor layer in a chamber; after the first heat treatment, introducing oxygen into the chamber in order to supply oxygen to the oxide semiconductor layer in the chamber; forming a source electrode and a drain electrode over the oxide semiconductor layer; and forming an oxide insulating film in contact with the oxide semiconductor layer, wherein after the first heat treatment, the oxide semiconductor layer includes crystals. - View Dependent Claims (24, 25, 26, 27, 28, 29, 30, 31)
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Specification