SEMICONDUCTOR DEVICE AND MANUFACTURING METHOD THEREOF
First Claim
1. A semiconductor device comprising:
- a gate electrode;
a gate insulating film over the gate electrode;
an oxide semiconductor layer over the gate insulating film;
a channel protective layer over the oxide semiconductor layer, wherein the channel protective layer overlaps a channel formation region of the oxide semiconductor layer;
a first buffer layer and a second buffer layer over the oxide semiconductor layer; and
a source electrode over the first buffer layer, and a drain electrode over the second buffer layer,wherein the first buffer layer and the second buffer layer include titanium oxide, and wherein a portion of the first buffer layer and a portion of the second buffer layer are in contact with an upper surface of the channel protective layer.
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Accused Products
Abstract
To provide a semiconductor device including a thin film transistor having excellent electric characteristics and high reliability and a manufacturing method of the semiconductor device with high mass productivity. The summary is that an inverted-staggered (bottom-gate) thin film transistor is included in which an oxide semiconductor film containing In, Ga, and Zn is used as a semiconductor layer, a channel protective layer is provided in a region that overlaps a channel formation region of the semiconductor layer, and a buffer layer is provided between the semiconductor layer and source and drain electrodes. An ohmic contact is formed by intentionally providing the buffer layer having a higher carrier concentration than the semiconductor layer between the semiconductor layer and the source and drain electrodes.
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Citations
22 Claims
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1. A semiconductor device comprising:
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a gate electrode; a gate insulating film over the gate electrode; an oxide semiconductor layer over the gate insulating film; a channel protective layer over the oxide semiconductor layer, wherein the channel protective layer overlaps a channel formation region of the oxide semiconductor layer; a first buffer layer and a second buffer layer over the oxide semiconductor layer; and a source electrode over the first buffer layer, and a drain electrode over the second buffer layer, wherein the first buffer layer and the second buffer layer include titanium oxide, and wherein a portion of the first buffer layer and a portion of the second buffer layer are in contact with an upper surface of the channel protective layer. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A manufacturing method of a semiconductor device, comprising the steps of:
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forming a gate electrode over a substrate; forming a gate insulating film over the gate electrode; forming a oxide semiconductor layer over the gate insulating film; forming a channel protective layer over the oxide semiconductor layer, wherein the channel protective layer overlaps a channel formation region of the oxide semiconductor layer; forming a buffer layer including titanium oxide over the oxide semiconductor layer; forming a first buffer layer and a second buffer layer by etching the buffer layer, and forming a source electrode over the first buffer layer; and forming a drain electrode over the second buffer layer, wherein the first buffer layer and the second buffer layer have a carrier concentration higher than the oxide semiconductor layer, and wherein the oxide semiconductor layer and the source electrode are electrically connected to each other through the first buffer layer, and the oxide semiconductor layer and the drain electrode are electrically connected to each other through the second buffer layer. - View Dependent Claims (11, 12, 13, 14, 15, 16)
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10. A manufacturing method of a semiconductor device, comprising the steps of:
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forming a gate electrode; forming a gate insulating film over the gate electrode; forming a oxide semiconductor layer over the gate insulating film; forming a channel protective layer over the oxide semiconductor layer, wherein the channel protective layer overlaps a channel formation region of the oxide semiconductor layer; forming a buffer layer including titanium oxide over the oxide semiconductor layer; forming a first buffer layer and a second buffer layer by etching the buffer layer, and forming a source electrode over the first buffer layer; and forming a drain electrode over the second buffer layer, wherein the first buffer layer and the second buffer layer have a carrier concentration higher than the oxide semiconductor layer, wherein the oxide semiconductor layer and the source electrode are electrically connected to each other through the first buffer layer, and the oxide semiconductor layer and the drain electrode are electrically connected to each other through the second buffer layer, and wherein the gate insulating film, the oxide semiconductor layer, and the channel protective layer are formed without being exposed to air. - View Dependent Claims (17, 18, 19, 20, 21, 22)
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Specification