Semiconductor device and method for manufacturing semiconductor device
First Claim
1. A method for manufacturing a semiconductor device, comprising the steps of:
- forming an oxide semiconductor layer;
forming a source electrode layer and a drain electrode layer over the oxide semiconductor layer; and
exposing a part of the oxide semiconductor layer to diluted hydrofluoric acid after the formation of the source electrode layer and the drain electrode layer,wherein a concentration of the diluted hydrofluoric acid is higher than 0.0001% and lower than or equal to 0.25%.
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Accused Products
Abstract
Provided is a method for manufacturing a transistor by which the defective shape of a semiconductor device is prevented in the case where a source electrode layer and a drain electrode layer are formed on an oxide semiconductor film. A source electrode layer and a drain electrode layer are formed each having a cross-sectional shape with which disconnection of a gate insulating film is unlikely to occur even when the gate insulating film over the source electrode layer and the drain electrode layer has a small thickness. An oxide semiconductor film having a crystal structure over an insulating surface is formed; an electrode layer on the oxide semiconductor film is formed; and a thickness of an exposed portion of the oxide semiconductor film is reduced by exposing the oxide semiconductor film to dilute hydrofluoric acid with a concentration higher than 0.0001% and lower than or equal to 0.25%.
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Citations
20 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; forming a source electrode layer and a drain electrode layer over the oxide semiconductor layer; and exposing a part of the oxide semiconductor layer to diluted hydrofluoric acid after the formation of the source electrode layer and the drain electrode layer, wherein a concentration of the diluted hydrofluoric acid is higher than 0.0001% and lower than or equal to 0.25%. - View Dependent Claims (2, 3, 4, 5)
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6. A method for manufacturing a semiconductor device, comprising the steps of:
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forming an oxide semiconductor layer over an insulating surface; forming a source electrode layer and a drain electrode layer over the oxide semiconductor layer; exposing a part of the oxide semiconductor layer to diluted hydrofluoric acid after the formation of the source electrode layer and the drain electrode layer; forming an insulating layer over the oxide semiconductor layer, the source electrode layer, and the drain electrode layer; and forming a gate electrode layer over the insulating layer, the gate electrode layer overlapping with the oxide semiconductor layer, wherein a concentration of the diluted hydrofluoric acid is higher than 0.0001% and lower than or equal to 0.25%. - View Dependent Claims (7, 8, 9, 10, 11)
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12. A method for manufacturing a semiconductor device, comprising the steps of:
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forming a first electrode layer over an insulating surface; forming a first insulating layer over the first electrode layer; forming an oxide semiconductor layer over the first insulating layer; forming a source electrode layer and a drain electrode layer over the oxide semiconductor layer; exposing a part of the oxide semiconductor layer to diluted hydrofluoric acid after the formation of the source electrode layer and the drain electrode layer; forming a second insulating layer over the oxide semiconductor layer, the source electrode layer, and the drain electrode layer; and forming a second electrode layer over the second insulating layer, the second electrode layer overlapping with the oxide semiconductor layer, wherein a concentration of the diluted hydrofluoric acid is higher than 0.0001% and lower than or equal to 0.25%. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20)
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Specification