Semiconductor device and method for manufacturing the same
First Claim
1. A method for manufacturing a semiconductor device, comprising steps of:
- forming a gate insulating film over a gate electrode;
forming an oxide semiconductor film over the gate insulating film, the oxide semiconductor film comprising indium, gallium, and zinc;
forming a conductive film over the oxide semiconductor film so that crystallinity of a first region of the oxide semiconductor film in contact with the conductive film is lowered, wherein the crystallinity of the first region is lower than crystallinity of a second region of the oxide semiconductor film, and wherein the second region is other than the first region and includes a channel region;
processing the conductive film to form a source electrode and a drain electrode so that a part of the first region is exposed by performing a first treatment;
removing part of the oxide semiconductor film so that the part of the first region is removed by performing a second treatment which is different from the first treatment; and
forming an insulating film over the oxide semiconductor film, the source electrode, and the drain electrode after removing the part of the first region, wherein the insulating film is in contact with the oxide semiconductor film at least between the source electrode and the drain electrode,wherein the first treatment is performed using a mask,wherein the second treatment is performed after removing the mask, andwherein an atomic percentage of gallium is greater than or equal to an atomic percentage of indium in the second region.
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Abstract
To provide a highly reliable semiconductor device by giving stable electrical characteristics to a transistor including an oxide semiconductor film. A gate electrode layer is formed over a substrate, a gate insulating film is formed over the gate electrode layer, an oxide semiconductor film is formed over the gate insulating film, a conductive film is formed over the oxide semiconductor film, so that a region in vicinity of an interface with the oxide semiconductor film in contact with the conductive film is made amorphous, heat treatment is performed, the conductive film is then processed to form a source electrode layer and a drain electrode layer, and a part of the amorphous region in the oxide semiconductor film which is exposed by formation of the source electrode layer and the drain electrode layer is removed.
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Citations
25 Claims
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1. A method for manufacturing a semiconductor device, comprising steps of:
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forming a gate insulating film over a gate electrode; forming an oxide semiconductor film over the gate insulating film, the oxide semiconductor film comprising indium, gallium, and zinc; forming a conductive film over the oxide semiconductor film so that crystallinity of a first region of the oxide semiconductor film in contact with the conductive film is lowered, wherein the crystallinity of the first region is lower than crystallinity of a second region of the oxide semiconductor film, and wherein the second region is other than the first region and includes a channel region; processing the conductive film to form a source electrode and a drain electrode so that a part of the first region is exposed by performing a first treatment; removing part of the oxide semiconductor film so that the part of the first region is removed by performing a second treatment which is different from the first treatment; and forming an insulating film over the oxide semiconductor film, the source electrode, and the drain electrode after removing the part of the first region, wherein the insulating film is in contact with the oxide semiconductor film at least between the source electrode and the drain electrode, wherein the first treatment is performed using a mask, wherein the second treatment is performed after removing the mask, and wherein an atomic percentage of gallium is greater than or equal to an atomic percentage of indium in the second region. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method for manufacturing a semiconductor device, comprising steps of:
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forming a gate insulating film over a gate electrode; forming an oxide semiconductor film over the gate insulating film, the oxide semiconductor film comprising indium, gallium, and zinc; introducing an element to a surface of the oxide semiconductor film by ion implantation method, ion doping method or plasma treatment so that crystallinity of a first region of the oxide semiconductor film including the surface of the oxide semiconductor film is lowered, wherein the crystallinity of the first region is lower than crystallinity of a second region of the oxide semiconductor film, and wherein the second region is other than the first region and includes a channel region; forming a source electrode and a drain electrode so that a part of the first region is exposed by performing a first treatment; removing part of the oxide semiconductor film so that the part of the first region is removed by performing a second treatment which is different from the first treatment; and forming an insulating film over the oxide semiconductor film, the source electrode, and the drain electrode after removing the part of the first region, wherein the insulating film is in contact with the oxide semiconductor film at least between the source electrode and the drain electrode, wherein an atomic percentage of gallium is greater than or equal to an atomic percentage of indium in the second region. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18)
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19. A method for manufacturing a semiconductor device, comprising steps of:
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forming an oxide semiconductor film; forming a conductive film over the oxide semiconductor film so that crystallinity of a first region of the oxide semiconductor film in contact with the conductive film is lowered, wherein the crystallinity of the first region is lower than crystallinity of a second region of the oxide semiconductor film, and wherein the second region is other than the first region and includes a channel region; processing the conductive film to form a source electrode and a drain electrode so that a part of the first region is exposed by performing a first treatment; and removing part of the oxide semiconductor film so that the part of the first region is removed by performing a second treatment which is different from the first treatment, wherein the first treatment is performed using a mask, and wherein the second treatment is performed after removing the mask. - View Dependent Claims (20, 21, 22, 23, 24, 25)
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Specification