Thin film transistor and display device
First Claim
1. A thin film transistor formed on an insulating substrate, comprising:
- a gate electrode formed on the insulating substrate;
a gate insulating film formed to cover the gate electrode;
a source electrode and a drain electrode that are formed on the gate insulating film with a predetermined distance to sandwich the gate electrode; and
a channel layer that includes an oxide semiconductor layer which is formed on the gate insulating film sandwiched between the source electrode and the drain electrode, and one end and the other end being electrically connected respectively to the source electrode and the drain electrode, whereinthe oxide semiconductor layer has two first regions each having a first resistance value, and a second region sandwiched between the two first regions and having a second resistance value higher than the first resistance values,a length of the second region is shorter than a length between an end part of the source electrode and an end part of the drain electrode,the source electrode and the drain electrode include at least one metal electrode which takes oxygen away from the oxide semiconductor layer and also supplies hydrogen to the oxide semiconductor layer, and are made of laminated metal electrodes obtained by laminating a plurality of metal electrodes,the laminated metal electrodes have stair-shaped steps that are formed to have at least a part of surfaces of the plurality of metal electrodes exposed, andone end and the other end of the oxide semiconductor layer are formed to cover the stair-shaped steps.
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Accused Products
Abstract
The invention provides a thin film transistor having current driving force that can be substantially improved. By heat treatment, the IGZO layer (45) from which oxygen is taken away by the titanium electrodes (65) becomes the low resistance regions (40b), and the IGZO layer (45) from which oxygen is not taken away remains as the high resistance region (40a). In this state, when the gate voltage is applied to the gate electrode (20), electrons in the low resistance regions (40b) near the boundaries with the high resistance region (40a) move respectively to the titanium electrode (65) sides. As a result, the length of the low resistance regions (40b) becomes short, and oppositely, the length of the high resistance region (40a) becomes longer by the size of the shortened low resistance regions. However, the electrical channel length (Le) becomes shorter than the source/drain interval space (Lch) as the limit resolution of the exposure device, and the current driving force becomes large.
14 Citations
18 Claims
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1. A thin film transistor formed on an insulating substrate, comprising:
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a gate electrode formed on the insulating substrate; a gate insulating film formed to cover the gate electrode; a source electrode and a drain electrode that are formed on the gate insulating film with a predetermined distance to sandwich the gate electrode; and a channel layer that includes an oxide semiconductor layer which is formed on the gate insulating film sandwiched between the source electrode and the drain electrode, and one end and the other end being electrically connected respectively to the source electrode and the drain electrode, wherein the oxide semiconductor layer has two first regions each having a first resistance value, and a second region sandwiched between the two first regions and having a second resistance value higher than the first resistance values, a length of the second region is shorter than a length between an end part of the source electrode and an end part of the drain electrode, the source electrode and the drain electrode include at least one metal electrode which takes oxygen away from the oxide semiconductor layer and also supplies hydrogen to the oxide semiconductor layer, and are made of laminated metal electrodes obtained by laminating a plurality of metal electrodes, the laminated metal electrodes have stair-shaped steps that are formed to have at least a part of surfaces of the plurality of metal electrodes exposed, and one end and the other end of the oxide semiconductor layer are formed to cover the stair-shaped steps. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A thin film transistor formed on an insulating substrate, comprising:
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a gate electrode formed on the insulating substrate; a gate insulating film formed to cover the gate electrode; a source electrode and a drain electrode that are formed on the gate insulating film with a predetermined distance to sandwich the gate electrode; and a channel layer that includes an oxide semiconductor layer which is formed on the gate insulating film sandwiched between the source electrode and the drain electrode, and one end and the other end being electrically connected respectively to the source electrode and the drain electrode, wherein the oxide semiconductor layer is an indium gallium zinc oxide layer, and has two first regions each having a first resistance value, and a second region sandwiched between the two first regions and having a second resistance value higher than the first resistance values, a length of the second region is shorter than a length between an end part of the source electrode and an end part of the drain electrode, the source electrode and the drain electrode respectively include at least one titanium electrode which takes oxygen away from the oxide semiconductor layer and also supplies hydrogen to the oxide semiconductor layer, and the titanium electrodes are in direct contact with the indium gallium zinc oxide layer. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17, 18)
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Specification