SEMICONDUCTOR DEVICE AND MANUFACTURING METHOD THEREOF
First Claim
1. A semiconductor device comprising:
- a gate electrode layer;
a gate insulating layer over the gate electrode layer;
an oxide semiconductor layer over the gate insulating layer;
an oxide semiconductor layer containing insulating oxide over the oxide semiconductor layer; and
a source electrode layer and a drain electrode layer over the oxide semiconductor layer containing insulating oxide,wherein the oxide semiconductor layer containing insulating oxide has an amorphous structure, andwherein the oxide semiconductor layer containing insulating oxide is electrically connected to the source electrode layer and the drain electrode layer.
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Accused Products
Abstract
An object is to reduce to reduce variation in threshold voltage to stabilize electric characteristics of thin film transistors each using an oxide semiconductor layer. An object is to reduce an off current. The thin film transistor using an oxide semiconductor layer is formed by stacking an oxide semiconductor layer containing insulating oxide over the oxide semiconductor layer so that the oxide semiconductor layer and source and drain electrode layers are in contact with each other with the oxide semiconductor layer containing insulating oxide interposed therebetween; whereby, variation in threshold voltage of the thin film transistors can be reduced and thus the electric characteristics can be stabilized. Further, an off current can be reduced.
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Citations
30 Claims
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1. A semiconductor device comprising:
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a gate electrode layer; a gate insulating layer over the gate electrode layer; an oxide semiconductor layer over the gate insulating layer; an oxide semiconductor layer containing insulating oxide over the oxide semiconductor layer; and a source electrode layer and a drain electrode layer over the oxide semiconductor layer containing insulating oxide, wherein the oxide semiconductor layer containing insulating oxide has an amorphous structure, and wherein the oxide semiconductor layer containing insulating oxide is electrically connected to the source electrode layer and the drain electrode layer. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A semiconductor device comprising:
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a gate electrode layer; a gate insulating layer over the gate electrode layer; an oxide semiconductor layer over the gate insulating layer; an oxide semiconductor layer containing insulating oxide over the oxide semiconductor layer; a buffer layer having n-type conductivity over the oxide semiconductor layer containing insulating oxide; and a source electrode layer and a drain electrode layer over the buffer layer, wherein the oxide semiconductor layer containing insulating oxide has an amorphous structure, wherein a conductivity of the buffer layer is higher than that of the oxide semiconductor layer; and wherein the oxide semiconductor layer containing insulating oxide is electrically connected to one of the source electrode layer and the drain electrode layer through the buffer layer. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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22. A method for manufacturing a semiconductor device comprising the steps of:
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forming a gate electrode layer over a substrate; forming a gate insulating layer over the gate electrode layer; forming a first oxide semiconductor film over the gate insulating layer by a sputtering method; forming a second oxide semiconductor film containing silicon oxide, over the first oxide semiconductor film, by a sputtering method using a target containing SiO2; etching the first oxide semiconductor film and the second oxide semiconductor film to form an oxide semiconductor layer and an oxide semiconductor layer containing SiO2; forming a conductive layer over the oxide semiconductor layer containing SiO2; and etching the conductive layer to form a source electrode layer and a drain electrode layer, wherein the target containing SiO2 contains SiO2 at from 0.1% by weight to 30% by weight. - View Dependent Claims (23, 24, 25, 26)
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27. A method for manufacturing a semiconductor device comprising the steps of:
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forming a gate electrode layer over a substrate; forming a gate insulating layer over the gate electrode layer; forming a first oxide semiconductor film over the gate insulating layer by a sputtering method; etching the first oxide semiconductor film to form an oxide semiconductor layer; forming a second oxide semiconductor film containing silicon oxide, over the oxide semiconductor layer, by a sputtering method using a target containing SiO2; etching the second oxide semiconductor film to form an oxide semiconductor layer containing SiO2 covering the oxide semiconductor layer; forming a conductive layer over the oxide semiconductor layer containing SiO2; and etching the conductive layer to form a source electrode layer and a drain electrode layer, wherein the target containing SiO2 contains SiO2 at from 0.1% by weight to 30% by weight. - View Dependent Claims (28, 29, 30)
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Specification