Logic circuit and semiconductor device
AssigneeSemiconductor Energy Laboratory Co., Ltd.
InventorsShunpei Yamazaki, Jun Koyama, Masashi Tsubuku, Kosei Noda
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Abstract
To reduce a leakage current of a transistor so that malfunction of a logic circuit can be suppressed. The logic circuit includes a transistor which includes an oxide semiconductor layer having a function of a channel formation layer and in which an off current is 1×10−13 A or less per micrometer in channel width. A first signal, a second signal, and a third signal that is a clock signal are input as input signals. A fourth signal and a fifth signal whose voltage states are set in accordance with the first to third signals which have been input are output as output signals.
Claims4
A method for manufacturing a semiconductor device comprising:
- the semiconductor device comprising:
- a scan line driver circuit comprising a transistor;
- and
- a pixel portion electrically connected to the scan line driver circuit,
- the transistor comprising:
- a gate electrode layer;
- a gate insulating layer over the gate electrode layer;
- an oxide semiconductor layer over the gate insulating layer;
- a source electrode layer and a drain electrode layer over the oxide semiconductor layer;
- and
- an oxide insulating layer over the oxide semiconductor layer, the source electrode layer, and the drain electrode layer,
- wherein the oxide insulating layer is in contact with the oxide semiconductor layer between the source electrode layer and the drain electrode layer,
- wherein the oxide semiconductor layer comprises a crystal, and
- wherein the oxide semiconductor layer comprises In, Ga, and Zn,
- the method comprising:
- performing a first heat treatment on the oxide semiconductor layer to reduce a hydrogen concentration of the oxide semiconductor layer;
- forming the source electrode layer and the drain electrode layer after performing the first heat treatment;
- forming the oxide insulating layer after forming the source electrode layer and the drain electrode layer;
- and
- performing a second heat treatment to supply oxygen to the oxide semiconductor layer after forming the oxide insulating layer.
Dependencies are inferred from the claim text.