SEMICONDUCTOR DEVICE AND MANUFACTURING METHOD THEREOF
First Claim
1. A method for manufacturing a semiconductor device, comprising:
- forming a first oxide semiconductor layer;
performing first heat treatment on the first oxide semiconductor layer to form a crystal region which is grown from a surface toward an inside of the first oxide semiconductor layer, wherein the crystal region includes crystals whose c-axis is oriented in a direction substantially perpendicular to the surface of the first oxide semiconductor layer;
forming a second oxide semiconductor layer over the first oxide semiconductor layer including the crystal region;
performing second heat treatment on the first oxide semiconductor layer and the second oxide semiconductor layer in an atmosphere including oxygen at a constant temperature so as to form c-axis oriented crystals grown from the crystal region in the second oxide semiconductor layer and so as to supply oxygen to the first oxide semiconductor layer and the second oxide semiconductor layer;
forming a conductive layer over the second oxide semiconductor layer on which the second heat treatment is performed;
forming a source electrode layer and a drain electrode layer by selectively etching the conductive layer;
forming an oxide insulating layer to cover the source electrode layer, the drain electrode layer, and the second oxide semiconductor layer, wherein the oxide insulating layer in contact with the second oxide semiconductor layer;
performing third heat treatment on the oxide insulating layer to supply oxygen to the second oxide semiconductor layer;
forming a gate electrode layer over the oxide insulating layer, the gate electrode layer overlapping with the second oxide semiconductor layer to which oxygen is supplied;
forming a nitride insulating layer including hydrogen over the gate electrode layer and the oxide insulating layer; and
performing fourth heat treatment on the nitride insulating layer to terminate dangling bonds with hydrogen, the dangling bonds existing at least in the first oxide semiconductor layer and the second oxide semiconductor layer and at an interface between the second oxide semiconductor layer and the oxide insulating layer.
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Accused Products
Abstract
An oxide semiconductor layer with excellent crystallinity is formed to enable manufacture of transistors with excellent electrical characteristics for practical application of a large display device, a high-performance semiconductor device, etc. By first heat treatment, a first oxide semiconductor layer is crystallized. A second oxide semiconductor layer is formed over the first oxide semiconductor layer. By second heat treatment, an oxide semiconductor layer including a crystal region having the c-axis oriented substantially perpendicular to a surface is efficiently formed and oxygen vacancies are efficiently filled. An oxide insulating layer is formed over and in contact with the oxide semiconductor layer. By third heat treatment, oxygen is supplied again to the oxide semiconductor layer. A nitride insulating layer containing hydrogen is formed over the oxide insulating layer. By fourth heat treatment, hydrogen is supplied at least to an interface between the second oxide semiconductor layer and the oxide insulating layer.
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Citations
24 Claims
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1. A method for manufacturing a semiconductor device, comprising:
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forming a first oxide semiconductor layer; performing first heat treatment on the first oxide semiconductor layer to form a crystal region which is grown from a surface toward an inside of the first oxide semiconductor layer, wherein the crystal region includes crystals whose c-axis is oriented in a direction substantially perpendicular to the surface of the first oxide semiconductor layer; forming a second oxide semiconductor layer over the first oxide semiconductor layer including the crystal region; performing second heat treatment on the first oxide semiconductor layer and the second oxide semiconductor layer in an atmosphere including oxygen at a constant temperature so as to form c-axis oriented crystals grown from the crystal region in the second oxide semiconductor layer and so as to supply oxygen to the first oxide semiconductor layer and the second oxide semiconductor layer; forming a conductive layer over the second oxide semiconductor layer on which the second heat treatment is performed; forming a source electrode layer and a drain electrode layer by selectively etching the conductive layer; forming an oxide insulating layer to cover the source electrode layer, the drain electrode layer, and the second oxide semiconductor layer, wherein the oxide insulating layer in contact with the second oxide semiconductor layer; performing third heat treatment on the oxide insulating layer to supply oxygen to the second oxide semiconductor layer; forming a gate electrode layer over the oxide insulating layer, the gate electrode layer overlapping with the second oxide semiconductor layer to which oxygen is supplied; forming a nitride insulating layer including hydrogen over the gate electrode layer and the oxide insulating layer; and performing fourth heat treatment on the nitride insulating layer to terminate dangling bonds with hydrogen, the dangling bonds existing at least in the first oxide semiconductor layer and the second oxide semiconductor layer and at an interface between the second oxide semiconductor layer and the oxide insulating layer. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method for manufacturing a semiconductor device, comprising:
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forming a gate electrode layer; forming a first oxide insulating layer over the gate electrode layer; forming a first oxide semiconductor layer over the gate electrode layer and the first oxide insulating layer; performing first heat treatment on the first oxide semiconductor layer to form a crystal region which is grown from a surface toward an inside of the first oxide semiconductor layer, wherein the crystal region includes crystals whose c-axis is oriented in a direction substantially perpendicular to the surface of the first oxide semiconductor layer; forming a second oxide semiconductor layer over the first oxide semiconductor layer including the crystal region; performing second heat treatment on the first oxide semiconductor layer and the second oxide semiconductor layer in an atmosphere including oxygen at a constant temperature so as to form c-axis oriented crystals grown from the crystal region in the second oxide semiconductor layer and so as to supply oxygen to the first oxide semiconductor layer and the second oxide semiconductor layer; forming a conductive layer over the second oxide semiconductor layer on which the second heat treatment is performed; forming a source electrode layer and a drain electrode layer by selectively etching the conductive layer; forming a second oxide insulating layer to cover the source electrode layer, the drain electrode layer, and the second oxide semiconductor layer, wherein the second oxide insulating layer in contact with the second oxide semiconductor layer; performing third heat treatment on the second oxide insulating layer to supply oxygen to the second oxide semiconductor layer; forming a nitride insulating layer including hydrogen over the second oxide insulating layer on which the third heat treatment is performed; and performing fourth heat treatment on the nitride insulating layer to terminate dangling bonds with hydrogen, the dangling bonds existing at least in the first oxide semiconductor layer and the second oxide semiconductor layer and at interfaces between the first oxide insulating layer and the first oxide semiconductor layer and between the second oxide insulating layer and the second oxide semiconductor layer. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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15. A method for manufacturing a semiconductor device, comprising:
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forming a first oxide semiconductor layer; performing first heat treatment to form a crystal region which is grown from a surface of the first oxide semiconductor layer in the first oxide semiconductor layer; forming a second oxide semiconductor layer over the first oxide semiconductor layer including the crystal region; performing second heat treatment in an atmosphere including oxygen to form crystals grown form the crystal region in the second oxide semiconductor layer; after performing the second heat treatment, forming an interlayer insulating layer including hydrogen over the second oxide semiconductor layer; and performing third heat treatment on the interlayer insulating layer. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 23, 24)
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Specification