Logic circuit and semiconductor device
First Claim
1. A semiconductor device comprising:
- a first transistor comprising a first terminal which is electrically connected to a high power supply potential line;
a second transistor comprising a gate terminal which is electrically connected to an input terminal, and a first terminal which is electrically connected to a gate terminal and a second terminal of the first transistor;
a third transistor comprising a gate terminal which is electrically connected to a pulse signal line, a first terminal which is electrically connected to a second terminal of the second transistor, and a second terminal which is electrically connected to a low power supply potential line;
a fourth transistor comprising a gate terminal which is electrically connected to the pulse signal line, a first terminal which is electrically connected to the gate terminal and the second terminal of the first transistor and the first terminal of the second transistor, and a second terminal which is electrically connected to an output terminal; and
a capacitor,wherein one terminal of the capacitor is electrically connected to the second terminal of the fourth transistor and the output terminal, andwherein a channel formation region of the fourth transistor comprises an oxide semiconductor.
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Accused Products
Abstract
A logic circuit includes a thin film transistor having a channel formation region formed using an oxide semiconductor, and a capacitor having terminals one of which is brought into a floating state by turning off the thin film transistor. The oxide semiconductor has a hydrogen concentration of 5×1019 (atoms/cm3) or less and thus substantially serves as an insulator in a state where an electric field is not generated. Therefore, off-state current of a thin film transistor can be reduced, leading to suppressing the leakage of electric charge stored in a capacitor, through the thin film transistor. Accordingly, a malfunction of the logic circuit can be prevented. Further, the excessive amount of current which flows in the logic circuit can be reduced through the reduction of off-state current of the thin film transistor, resulting in low power consumption of the logic circuit.
261 Citations
32 Claims
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1. A semiconductor device comprising:
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a first transistor comprising a first terminal which is electrically connected to a high power supply potential line; a second transistor comprising a gate terminal which is electrically connected to an input terminal, and a first terminal which is electrically connected to a gate terminal and a second terminal of the first transistor; a third transistor comprising a gate terminal which is electrically connected to a pulse signal line, a first terminal which is electrically connected to a second terminal of the second transistor, and a second terminal which is electrically connected to a low power supply potential line; a fourth transistor comprising a gate terminal which is electrically connected to the pulse signal line, a first terminal which is electrically connected to the gate terminal and the second terminal of the first transistor and the first terminal of the second transistor, and a second terminal which is electrically connected to an output terminal; and a capacitor, wherein one terminal of the capacitor is electrically connected to the second terminal of the fourth transistor and the output terminal, and wherein a channel formation region of the fourth transistor comprises an oxide semiconductor. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A semiconductor device comprising:
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a first transistor comprising a first terminal which is electrically connected to a high power supply potential line; a second transistor comprising a gate terminal which is electrically connected to a pulse signal line, and a first terminal which is electrically connected to a gate terminal and a second terminal of the first transistor; a third transistor comprising a gate terminal which is electrically connected to an input terminal, a first terminal which is electrically connected to a second terminal of the second transistor, and a second terminal which is electrically connected to a low power supply potential line; a fourth transistor comprising a gate terminal which is electrically connected to the pulse signal line, a first terminal which is electrically connected to the second terminal of the second transistor and the first terminal of the third transistor, and a second terminal which is electrically connected to an output terminal; and a capacitor, wherein one terminal of the capacitor is electrically connected to the second terminal of the fourth transistor and the output terminal, and wherein a channel formation region of the fourth transistor comprises an oxide semiconductor. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
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17. A semiconductor device comprising:
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a first transistor comprising a gate terminal and a first terminal which are electrically connected to a high power supply potential line; a second transistor comprising a gate terminal which is electrically connected to an input terminal, and a first terminal which is electrically connected to a second terminal of the first transistor; a third transistor comprising a gate terminal which is electrically connected to a pulse signal line, a first terminal which is electrically connected to a second terminal of the second transistor, and a second terminal which is electrically connected to a low power supply potential line; a fourth transistor comprising a gate terminal which is electrically connected to the pulse signal line, a first terminal which is electrically connected to the second terminal of the first transistor and the first terminal of the second transistor, and a second terminal which is electrically connected to an output terminal; and a capacitor, wherein one terminal of the capacitor is electrically connected to the second terminal of the fourth transistor and the output terminal, and wherein a channel formation region of the fourth transistor comprises an oxide semiconductor. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24)
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25. A semiconductor device comprising:
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a first transistor comprising a gate terminal and a first terminal which are electrically connected to a high power supply potential line; a second transistor comprising a gate terminal which is electrically connected to a pulse signal line, and a first terminal which is electrically connected to a second terminal of the first transistor; a third transistor comprising a gate terminal which is electrically connected to an input terminal, a first terminal which is electrically connected to a second terminal of the second transistor, and a second terminal which is electrically connected to a low power supply potential line; a fourth transistor comprising a gate terminal which is electrically connected to the pulse signal line, a first terminal which is electrically connected to the second terminal of the second transistor and the first terminal of the third transistor, and a second terminal which is electrically connected to an output terminal; and a capacitor, wherein one terminal of the capacitor is electrically connected to the second terminal of the fourth transistor and the output terminal, and wherein a channel formation region of the fourth transistor comprises an oxide semiconductor. - View Dependent Claims (26, 27, 28, 29, 30, 31, 32)
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Specification