Semiconductor device and method for manufacturing the same
First Claim
1. A method for manufacturing a semiconductor device, comprising the steps of:
- forming a gate electrode layer over a substrate having an insulating surface;
forming a gate insulating layer over the gate electrode layer;
forming an In—
Ga—
Zn—
O-based oxide semiconductor layer over the gate insulating layer;
performing a first heat treatment after the oxide semiconductor layer is formed;
forming source and drain electrode layers over the oxide semiconductor layer after performing the first heat treatment;
forming an inorganic insulating layer in contact with part of the oxide semiconductor layer, over the gate insulating layer, the oxide semiconductor layer, and the source and drain electrode layers;
performing a second heat treatment after the inorganic insulating layer is formed; and
forming a planarization layer comprising a resin material over the inorganic insulating layer,wherein an amount of change in threshold voltage according to a BT test applied to a transistor including the oxide semiconductor layer is less than or equal to 2 V,wherein the BT test is performed under conditions in which a temperature of the substrate is 150°
C., an electrical field applied to the gate insulating layer is 2 MV/cm, and a time of application of the electrical field is one hour,wherein the second heat treatment is performed at a temperature higher than or equal to 100°
C. and lower than a maximum temperature in the first heat treatment, andwherein the oxide semiconductor layer is at least partially microcrystalline.
1 Assignment
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Accused Products
Abstract
An object is to provide a high reliability thin film transistor using an oxide semiconductor layer which has stable electric characteristics. In the thin film transistor in which an oxide semiconductor layer is used, the amount of change in threshold voltage of the thin film transistor before and after a BT test is made to be 2 V or less, preferably 1.5 V or less, more preferably 1 V or less, whereby the semiconductor device which has high reliability and stable electric characteristics can be manufactured. In particular, in a display device which is one embodiment of the semiconductor device, a malfunction such as display unevenness due to change in threshold voltage can be reduced.
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Citations
45 Claims
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1. A method for manufacturing a semiconductor device, comprising the steps of:
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forming a gate electrode layer over a substrate having an insulating surface; forming a gate insulating layer over the gate electrode layer; forming an In—
Ga—
Zn—
O-based oxide semiconductor layer over the gate insulating layer;performing a first heat treatment after the oxide semiconductor layer is formed; forming source and drain electrode layers over the oxide semiconductor layer after performing the first heat treatment; forming an inorganic insulating layer in contact with part of the oxide semiconductor layer, over the gate insulating layer, the oxide semiconductor layer, and the source and drain electrode layers; performing a second heat treatment after the inorganic insulating layer is formed; and forming a planarization layer comprising a resin material over the inorganic insulating layer, wherein an amount of change in threshold voltage according to a BT test applied to a transistor including the oxide semiconductor layer is less than or equal to 2 V, wherein the BT test is performed under conditions in which a temperature of the substrate is 150°
C., an electrical field applied to the gate insulating layer is 2 MV/cm, and a time of application of the electrical field is one hour,wherein the second heat treatment is performed at a temperature higher than or equal to 100°
C. and lower than a maximum temperature in the first heat treatment, andwherein the oxide semiconductor layer is at least partially microcrystalline. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 14, 16, 18, 28, 31, 41)
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10. A method for manufacturing a semiconductor device, comprising the steps of:
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forming a gate electrode layer over a substrate having an insulating surface; forming a gate insulating layer over the gate electrode layer; forming an In—
Ga—
Zn—
O-based oxide semiconductor layer over the gate insulating layer;performing a first heat treatment after the oxide semiconductor layer is formed; forming source and drain electrode layers over the oxide semiconductor layer after performing the first heat treatment; forming an inorganic insulating layer in contact with part of the oxide semiconductor layer, over the gate insulating layer, the oxide semiconductor layer, and the source and drain electrode layers; performing a second heat treatment after the inorganic insulating layer is formed; and forming a planarization layer comprising a resin material over the inorganic insulating layer, wherein the second heat treatment is performed at a temperature higher than or equal to 100°
C. and lower than a maximum temperature in the first heat treatment, andwherein the oxide semiconductor layer is at least partially microcrystalline. - View Dependent Claims (11, 12, 13, 15, 17, 19, 29, 32, 42, 45)
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20. A method for manufacturing a semiconductor device, comprising the steps of:
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forming a gate electrode layer over a substrate having an insulating surface; forming a gate insulating layer over the gate electrode layer; forming an In—
Ga—
Zn—
O-based oxide semiconductor layer by sputtering over the gate insulating layer, wherein the substrate is heated at a temperature higher than or equal to 400°
C. and lower than or equal to 700°
C. during the sputtering;performing a first heat treatment after the oxide semiconductor layer is formed; forming source and drain electrode layers over the oxide semiconductor layer after performing the first heat treatment; forming an inorganic insulating layer in contact with part of the oxide semiconductor layer, over the gate insulating layer, the oxide semiconductor layer, and the source and drain electrode layers; performing a second heat treatment after the inorganic insulating layer is formed; and forming a planarization layer comprising a resin material over the inorganic insulating layer, wherein an amount of change in threshold voltage according to a BT test applied to a transistor including the oxide semiconductor layer is less than or equal to 2 V, wherein the BT test is performed under conditions in which a temperature of the substrate is 150°
C., an electrical field applied to the gate insulating layer is 2 MV/cm, and a time of application of the electrical field is one hour,wherein the second heat treatment is performed at a temperature higher than or equal to 100°
C. and lower than a maximum temperature in the first heat treatment, andwherein the oxide semiconductor layer is at least partially microcrystalline. - View Dependent Claims (21, 22, 23, 24, 25, 26, 27, 30, 33, 43)
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34. A method for manufacturing a semiconductor device, comprising the steps of:
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forming a gate electrode layer over a substrate having an insulating surface; forming a gate insulating layer over the gate electrode layer; forming an In—
Ga—
Zn—
O-based oxide semiconductor layer by sputtering over the gate insulating layer, wherein the substrate is heated at a temperature higher than or equal to 400°
C. and lower than or equal to 700°
C. during the sputtering;performing a first heat treatment after the oxide semiconductor layer is formed; forming source and drain electrode layers over the oxide semiconductor layer after performing the first heat treatment; forming an inorganic insulating layer in contact with part of the oxide semiconductor layer, over the gate insulating layer, the oxide semiconductor layer, and the source and drain electrode layers; performing a second heat treatment after the inorganic insulating layer is formed; and forming a planarization layer comprising a resin material over the inorganic insulating layer, wherein the second heat treatment is performed at a temperature higher than or equal to 100°
C. and lower than a maximum temperature in the first heat treatment, andwherein the oxide semiconductor layer is at least partially microcrystalline. - View Dependent Claims (35, 36, 37, 38, 39, 40, 44)
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Specification