Semiconductor device and manufacturing method thereof
First Claim
1. A semiconductor device comprising:
- a substrate;
a gate electrode over the substrate;
a gate insulating layer over the gate electrode;
a first semiconductor layer over and in direct contact with the gate insulating layer; and
a source electrode and a drain electrode each over the gate insulating layer and electrically connected to the first semiconductor layer;
wherein a first angle formed between an upper surface of the substrate and an upper end portion of a side surface of the source electrode is greater than a second angle formed between the upper surface of the substrate and a lower end portion of the side surface of the source electrode, andwherein a third angle formed between the upper surface of the substrate and an upper end portion of a side surface of the drain electrode is greater than a fourth angle formed between the upper surface of the substrate and a lower end portion of the side surface of the drain electrode.
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Accused Products
Abstract
A structure by which electric-field concentration which might occur between a source electrode and a drain electrode in a bottom-gate thin film transistor is relaxed and deterioration of the switching characteristics is suppressed, and a manufacturing method thereof. A bottom-gate thin film transistor in which an oxide semiconductor layer is provided over a source and drain electrodes is manufactured, and angle θ1 of the side surface of the source electrode which is in contact with the oxide semiconductor layer and angle θ2 of the side surface of the drain electrode which is in contact with the oxide semiconductor layer are each set to be greater than or equal to 20° and less than 90°, so that the distance from the top edge to the bottom edge in the side surface of each electrode is increased.
189 Citations
22 Claims
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1. A semiconductor device comprising:
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a substrate; a gate electrode over the substrate; a gate insulating layer over the gate electrode; a first semiconductor layer over and in direct contact with the gate insulating layer; and a source electrode and a drain electrode each over the gate insulating layer and electrically connected to the first semiconductor layer; wherein a first angle formed between an upper surface of the substrate and an upper end portion of a side surface of the source electrode is greater than a second angle formed between the upper surface of the substrate and a lower end portion of the side surface of the source electrode, and wherein a third angle formed between the upper surface of the substrate and an upper end portion of a side surface of the drain electrode is greater than a fourth angle formed between the upper surface of the substrate and a lower end portion of the side surface of the drain electrode. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A semiconductor device comprising:
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an n-channel transistor comprising; a gate electrode over a substrate; a gate insulating layer over the gate electrode; a first oxide semiconductor layer over and in direct contact with the gate insulating layer; a source electrode and a drain electrode each over the gate insulating layer and electrically connected to the first oxide semiconductor layer; a first oxide film on a side surface of the source electrode; and a second oxide film on a side surface of the drain electrode, wherein a first angle formed between an upper surface of the substrate and an upper end portion of the side surface of the source electrode is greater than a second angle formed between the upper surface of the substrate and a lower end portion of the side surface of the source electrode, wherein a third angle formed between the upper surface of the substrate and an upper end portion of the side surface of the drain electrode is greater than a fourth angle formed between the upper surface of the substrate and a lower end portion of the side surface of the drain electrode, and wherein the lower end portion of the source electrode and the lower end portion of the drain electrode are in contact with the first oxide semiconductor layer. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
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Specification