Semiconductor device and method for manufacturing the same
AssigneeSemiconductor Energy Laboratory Co., Ltd.
InventorsShunpei YAMAZAKI, Takahiro TSUJI, Kunihiko SUZUKI
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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.
Claims17
(canceled)
A method for manufacturing a semiconductor device, comprising:
- forming a gate electrode;
- forming a gate insulating layer over the gate electrode;
- forming an oxide semiconductor layer containing an In—Ga—Zn—O-based oxide semiconductor over the gate insulating layer,
- performing first heat treatment on the oxide semiconductor layer in an inert gas atmosphere to dehydrate or dehydrogenate the oxide semiconductor layer;
- forming source and drain electrodes over the oxide semiconductor layer;
- forming an inorganic insulating layer over the oxide semiconductor layer and the source and drain electrodes;
- and
- performing second heat treatment on the inorganic insulating layer,
- wherein:
- in the In—Ga—Zn—O-based oxide semiconductor, a content of In is larger than or equal to a content of Ga, and a content of Zn is smaller than a sum of the content of In and the content of Ga.
A method for manufacturing a semiconductor device, comprising:
- forming a gate electrode;
- forming a gate insulating layer over the gate electrode;
- forming an oxide semiconductor layer containing an In—Ga—Zn—O-based oxide semiconductor over the gate insulating layer,
- performing first heat treatment on the oxide semiconductor layer in an inert gas atmosphere to dehydrate or dehydrogenate the oxide semiconductor layer;
- forming source and drain electrodes over the oxide semiconductor layer;
- forming an inorganic insulating layer over the oxide semiconductor layer and the source and drain electrodes;
- performing second heat treatment on the inorganic insulating layer;
- and
- forming an electrode layer electrically connected to one of the source and drain electrodes through an opening provided in the inorganic insulating layer, wherein:
- in the In—Ga—Zn—O-based oxide semiconductor, a content of In is larger than or equal to a content of Ga, and a content of Zn is smaller than a sum of the content of In and the content of Ga.
Dependencies are inferred from the claim text.