SEMICONDUCTOR DEVICE AND MANUFACTURING METHOD THEREOF
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Abstract
An object is to provide a highly reliable semiconductor device including a thin film transistor having stable electric characteristics. In addition, another object is to manufacture a highly reliable semiconductor device at low cost with high productivity. In a method for manufacturing a semiconductor device including a thin film transistor including an oxide semiconductor layer as a channel formation region, the oxide semiconductor layer is heated under a nitrogen atmosphere to lower its resistance, thereby forming a low-resistance oxide semiconductor layer. Further, resistance of a region of the low-resistance oxide semiconductor layer, which is overlapped with a gate electrode layer, is selectively increased, thereby forming a high-resistance oxide semiconductor layer. Resistance of the oxide semiconductor layer is increased by forming a silicon oxide film in contact with the oxide semiconductor layer by a sputtering method.
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Citations
17 Claims
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1. (canceled)
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2. A method for manufacturing a semiconductor device, comprising the steps of:
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forming an oxide semiconductor layer comprising indium and zinc over a substrate; heating the oxide semiconductor layer at 200°
C. or higher under a nitrogen atmosphere;forming a source electrode layer and a drain electrode layer electrically connected to the oxide semiconductor layer after the heating step; and forming an insulating film comprising silicon and oxygen over the oxide semiconductor layer, the source electrode layer, and the drain electrode layer, wherein the insulating film is in contact with part of the oxide semiconductor layer. - View Dependent Claims (3, 4, 5, 6)
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7. A method for manufacturing a semiconductor device, comprising the steps of:
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forming an oxide semiconductor layer comprising indium and zinc over a substrate; first heating the oxide semiconductor layer at 200°
C. or higher under a nitrogen atmosphere;forming a source electrode layer and a drain electrode layer electrically connected to the oxide semiconductor layer after the first heating step; forming an insulating film comprising silicon and oxygen over the oxide semiconductor layer, the source electrode layer, and the drain electrode layer; and second heating the insulating film, wherein the insulating film is in contact with part of the oxide semiconductor layer. - View Dependent Claims (8, 9, 10, 11, 12)
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13. A method for manufacturing a semiconductor device, comprising the steps of:
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forming a first oxide semiconductor layer comprising indium and zinc over a substrate; heating the first oxide semiconductor layer at 200°
C. or higher under a nitrogen atmosphere to reduce its resistance, so that a second oxide semiconductor layer is formed;forming a conductive film electrically connected to the second oxide semiconductor layer; selectively etching the conductive film to expose part of the second oxide semiconductor layer and to form a source electrode layer and a drain electrode layer; and forming an insulating film comprising silicon and oxygen over the second oxide semiconductor layer, the source electrode layer, and the drain electrode layer, wherein the second oxide semiconductor layer includes a first region and a second region, wherein the first region is in contact with the insulating film and the second region is in contact with one of the source electrode layer and the drain electrode layer, and wherein the first region has a higher resistance than the second region. - View Dependent Claims (14, 15, 16, 17)
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Specification