Thin film transistors using multiple active channel layers
First Claim
1. A thin film transistor fabrication method, comprising:
- depositing a gate dielectric layer over a gate electrode and a substrate;
forming an active channel over the gate dielectric layer, the forming comprising;
depositing one or more gate control layers comprising oxygen, nitrogen, and one or more elements selected from the group consisting of zinc, indium, tin, cadmium and gallium having a first composition, at least one or the one or more gate control layers is in contact with the gate dielectric layer;
depositing one or more bulk layers in contact with at least one of the one or more gate control layers, the one or more bulk layers comprising oxygen, nitrogen, and one or more elements selected from the group consisting of zinc, indium, tin, cadmium and gallium having a second composition different than the first composition; and
depositing one or more back channel interface control layers in contact with at least one of the one or more bulk layers, the one or more back channel interface control layers comprising oxygen, nitrogen, and one or more elements selected from the group consisting of zinc, indium, tin, cadmium and gallium having a third composition different than one or more of the first composition and the second composition;
depositing a conductive layer on the topmost layer of the one or more back channel interface control layers; and
patterning the conductive layer to define source and drain electrodes and expose the topmost layer of the one or more back channel interface control layers.
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Abstract
Embodiments disclosed herein generally relate to TFTs and methods of fabricating the TFTs. In TFTs, the active channel carries the current between the source and drain electrodes. By tailoring the composition of the active channel, the current can be controlled. The active channel may be divided into three layers, a gate control layer, a bulk layer, and an interface control layer. The separate layers may have different compositions. Each of the gate control, bulk and interface control layers may additionally comprise multiple layers that may have different compositions. The composition of the various layers of the active channel comprise oxygen, nitrogen, and one or more elements selected from the group consisting of zinc, indium, cadmium, tin, gallium and combinations thereof. By varying the composition among the layers, the mobility, carrier concentration and conductivity of the various layers may be controlled to produce a TFT having desired properties.
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Citations
15 Claims
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1. A thin film transistor fabrication method, comprising:
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depositing a gate dielectric layer over a gate electrode and a substrate; forming an active channel over the gate dielectric layer, the forming comprising; depositing one or more gate control layers comprising oxygen, nitrogen, and one or more elements selected from the group consisting of zinc, indium, tin, cadmium and gallium having a first composition, at least one or the one or more gate control layers is in contact with the gate dielectric layer; depositing one or more bulk layers in contact with at least one of the one or more gate control layers, the one or more bulk layers comprising oxygen, nitrogen, and one or more elements selected from the group consisting of zinc, indium, tin, cadmium and gallium having a second composition different than the first composition; and depositing one or more back channel interface control layers in contact with at least one of the one or more bulk layers, the one or more back channel interface control layers comprising oxygen, nitrogen, and one or more elements selected from the group consisting of zinc, indium, tin, cadmium and gallium having a third composition different than one or more of the first composition and the second composition; depositing a conductive layer on the topmost layer of the one or more back channel interface control layers; and patterning the conductive layer to define source and drain electrodes and expose the topmost layer of the one or more back channel interface control layers. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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Specification