Manufacturing method of semiconductor device
AssigneeSemiconductor Energy Laboratory Co., Ltd.
InventorShunpei YAMAZAKI
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Abstract
One object is to have stable electrical characteristics and high reliability and to manufacture a semiconductor device including a semi-conductive oxide film. Film formation is performed by a sputtering method using a target in which gallium oxide is added to a material that is easy to volatilize compared to gallium when the material is heated at 400° C. to 700° C. like zinc, and a formed film is heated at 400° C. to 700° C., whereby the added material is segregated in the vicinity of a surface of the film and the oxide is crystallized. Further, a semi-conductive oxide film is deposited thereover, whereby a semi-conductive oxide having a crystal which succeeds a crystal structure of the oxide that is crystallized by heat treatment is formed.
Claims12
A manufacturing method of a semiconductor device, comprising the steps of:
- forming a first film that contains an oxide including at least a first metal element and a second metal element, over a substrate;
- heating the first film to form a first layer that contains a crystal of an oxide including the first metal element as a main metal component and a second layer that is on a side closer to the substrate than the first layer and contains an oxide including the second metal element as a main metal component;
- forming a second film that is in contact with the first layer and contains an oxide;
- and
- heating the first layer and the second film,
- wherein a concentration of sodium in at least one of the first layer and the second film is lower than 5×1016 cm−3.
A manufacturing method of a semiconductor device, comprising the steps of:
- forming a first film that contains an oxide including at least a first metal element and a second metal element, over a substrate;
- heating the first film to form a first layer that contains a crystal of an oxide including the first metal element as a main metal component and a second layer that is on a side closer to the substrate than the first layer and contains an oxide including the second metal element as a main metal component;
- forming a second film that is in contact with the first layer and contains an oxide;
- and
- heating the first layer and the second film to form a third layer from the first layer and the second film,
- wherein a concentration of sodium in at least one of the first layer and the second film is lower than 5×1016 cm−3, and
- wherein a carrier concentration of the third layer is lower than 1×1014 cm−3.
A semiconductor device comprising:
- a gate electrode over a substrate;
- an oxide semiconductor layer with a gate insulating film between the gate electrode and the oxide semiconductor layer;
- and
- a source electrode and a drain electrode over the oxide semiconductor layer,
- wherein a concentration of sodium in the oxide semiconductor layer is lower than 5×1016 cm−3, and
- wherein a carrier concentration of the oxide semiconductor layer is lower than 1×1014 cm−3.
Dependencies are inferred from the claim text.