Process for making thin film field effect transistors using zinc oxide
First Claim
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1. A method for forming a thin film transistor, comprising:
- blanket depositing a zinc oxide layer over an entire substrate surface;
depositing a conductive metal layer over the zinc oxide layer;
depositing a mask;
etching the conductive metal layer and zinc oxide layer in a first etching step in a single process with the same etchant using the mask to expose a gate dielectric layer;
removing the mask; and
thenpatterning and etching the conductive metal layer in a second etching step to expose the zinc oxide layer and define source and drain electrodes.
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Abstract
The present invention comprises a method of forming a zinc oxide based thin film transistor by blanket depositing the zinc oxide layer and the source-drain metal layer and then wet etching through the zinc oxide while etching through the source-drain electrode layer. Thereafter, the active channel is formed by dry etching the source-drain electrode layer without effectively etching the zinc oxide layer.
64 Citations
19 Claims
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1. A method for forming a thin film transistor, comprising:
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blanket depositing a zinc oxide layer over an entire substrate surface; depositing a conductive metal layer over the zinc oxide layer; depositing a mask; etching the conductive metal layer and zinc oxide layer in a first etching step in a single process with the same etchant using the mask to expose a gate dielectric layer; removing the mask; and
thenpatterning and etching the conductive metal layer in a second etching step to expose the zinc oxide layer and define source and drain electrodes. - View Dependent Claims (2, 3, 4, 5, 6, 18)
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7. A method for forming a bottom gate thin film transistor, comprising:
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depositing a zinc oxide layer over a gate electrode and a gate dielectric layer; depositing a metal layer over the zinc oxide layer; depositing a first mask; wet etching the metal layer and the zinc oxide layer using the first mask; removing the first mask; and patterning and dry etching the metal layer to expose the zinc oxide layer and define source and drain electrodes. - View Dependent Claims (8, 9, 10, 11, 12, 19)
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13. A method for forming a top gate thin film transistor, comprising:
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depositing an underlayer on a substrate; depositing a zinc oxide layer over the underlayer; depositing a metal layer over the zinc oxide layer; depositing a mask; wet etching the metal layer and the zinc oxide layer using the mask; removing the mask; and patterning and dry etching the metal layer to expose the zinc oxide layer and define source and drain electrodes. - View Dependent Claims (14, 15, 16, 17)
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Specification