Method of fabricating a stacked oxide material for thin film transistor
First Claim
1. A manufacturing method of a semiconductor device comprising the steps of:
- forming a first electrode over a substrate;
forming a first oxide semiconductor film over the first electrode;
performing first heat treatment to the first oxide semiconductor film to cause crystal growth from a surface to an inside portion of the first oxide semiconductor film;
forming a second oxide semiconductor film over the first oxide semiconductor film;
performing second heat treatment to the second oxide semiconductor film to cause crystal growth in the second oxide semiconductor film;
etching the first oxide semiconductor film and the second oxide semiconductor film so as to have an island shape;
forming a second electrode over the second oxide semiconductor film;
forming a gate insulating film covering the first electrode, the first oxide semiconductor film, the second oxide semiconductor film, and the second electrode; and
forming a gate electrode over the gate insulating film.
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Accused Products
Abstract
Objects are to provide a semiconductor device for high power application in which a novel semiconductor material having high productivity is used and to provide a semiconductor device having a novel structure in which a novel semiconductor material is used. The present invention is a vertical transistor and a vertical diode each of which has a stacked body of an oxide semiconductor in which a first oxide semiconductor film having crystallinity and a second oxide semiconductor film having crystallinity are stacked. An impurity serving as an electron donor (donor) which is contained in the stacked body of an oxide semiconductor is removed in a step of crystal growth; therefore, the stacked body of an oxide semiconductor is highly purified and is an intrinsic semiconductor or a substantially intrinsic semiconductor whose carrier density is low. The stacked body of an oxide semiconductor has a wider band gap than a silicon semiconductor.
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Citations
31 Claims
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1. A manufacturing method of a semiconductor device comprising the steps of:
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forming a first electrode over a substrate; forming a first oxide semiconductor film over the first electrode; performing first heat treatment to the first oxide semiconductor film to cause crystal growth from a surface to an inside portion of the first oxide semiconductor film; forming a second oxide semiconductor film over the first oxide semiconductor film; performing second heat treatment to the second oxide semiconductor film to cause crystal growth in the second oxide semiconductor film; etching the first oxide semiconductor film and the second oxide semiconductor film so as to have an island shape; forming a second electrode over the second oxide semiconductor film; forming a gate insulating film covering the first electrode, the first oxide semiconductor film, the second oxide semiconductor film, and the second electrode; and forming a gate electrode over the gate insulating film. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A manufacturing method of a semiconductor device comprising the steps of:
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forming a first electrode over a substrate; forming a first oxide semiconductor film over the first electrode; performing first heat treatment to the first oxide semiconductor film to cause crystal growth from a surface to an inside portion of the first oxide semiconductor film; forming a second oxide semiconductor film over the first oxide semiconductor film; forming a conductive film over the second oxide semiconductor film; performing second heat treatment to the second oxide semiconductor film to cause crystal growth in the second oxide semiconductor film; forming a second electrode by etching the conductive film; etching the first oxide semiconductor film and the second oxide semiconductor film so as to have an island shape; forming a gate insulating film covering the first electrode, the first oxide semiconductor film, the second oxide semiconductor film and the second electrode; and forming a gate electrode over the gate insulating film.
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15. A manufacturing method of a semiconductor device comprising the steps of:
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forming a first electrode over a substrate; forming a first oxide semiconductor film over the first electrode; performing first heat treatment to the first oxide semiconductor film to cause crystal growth from a surface to an inside portion of the first oxide semiconductor film; forming a second oxide semiconductor film having crystallinity over the first oxide semiconductor film by a sputtering method while heating is performed; etching the first oxide semiconductor film and the second oxide semiconductor film so as to have an island shape; forming a second electrode over the second oxide semiconductor film; forming a gate insulating film covering the first electrode, the first oxide semiconductor film, the second oxide semiconductor film, and the second electrode; and forming a gate electrode over the gate insulating film.
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16. A semiconductor device comprising:
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a first electrode formed over a substrate; a stacked body of an oxide semiconductor formed over the first electrode, the stacked body comprising; a first oxide semiconductor film having crystallinity with a crystal grown from a surface to an inside portion; and a second oxide semiconductor film having crystallinity over the first oxide semiconductor film; a second electrode formed over the stacked body of the oxide semiconductor; a gate insulating film covering the first electrode, the stacked body of the oxide semiconductor, and the second electrode; and a third electrode having a ring shape and facing at least a side surface of the stacked body of the oxide semiconductor with the gate insulating film provided therebetween. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30)
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31. A semiconductor device comprising:
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a first electrode formed over a substrate; a stacked body of an oxide semiconductor formed over the first electrode, the stacked body comprising; a first oxide semiconductor film having crystallinity with a crystal grown from a surface to an inside portion; and a second oxide semiconductor film having crystallinity over the first oxide semiconductor film; a second electrode being over the stacked body of the oxide semiconductor and being formed inside a periphery of the stacked body of the oxide semiconductor; a gate insulating film covering the first electrode, the stacked body of the oxide semiconductor, and the second electrode; and a third electrode having a ring shape and facing at least a side surface of the stacked body of the oxide semiconductor and a side surface of the second electrode with the gate insulating film provided therebetween.
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Specification