Semiconductor device
AssigneeSemiconductor Energy Laboratory Co., Ltd.
InventorsShunpei Yamazaki, Masahiko Hayakawa, Daisuke Matsubayashi
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Abstract
A semiconductor device includes a dual-gate transistor in which an oxide semiconductor film is provided between a first gate electrode and a second gate electrode. In the channel width direction of the transistor, a side surface of each of the first and second gate electrodes is on the outer side of a side surface of the oxide semiconductor film. The first or second gate electrode faces the side surface of the oxide semiconductor film with the gate insulating film provided between the first or second gate electrode and the oxide semiconductor film.
Claims22
A semiconductor device comprising:
- a transistor comprising:
- a first gate electrode over an insulating surface;
- an oxide semiconductor film overlapping with the first gate electrode;
- a first gate insulating film between the first gate electrode and the oxide semiconductor film;
- a pair of electrodes electrically connected to the oxide semiconductor film;
- a second gate insulating film over and in contact with a top surface of the oxide semiconductor film;
- and
- a second gate electrode overlapping with the oxide semiconductor film with the second gate insulating film positioned therebetween,
- wherein in a log-log graph of an amount of change in a threshold voltage of the transistor with respect to a time during which a load is applied to the transistor, an interval of a logarithmic scale on a horizontal axis is equal to an interval of a logarithmic scale on a vertical axis,
- wherein in the log-log graph, an angle between a power approximate line of the amount of change in the threshold voltage with respect to the time and a straight line of the amount of change in the threshold voltage with respect to the time is 0 V is less than or equal to 30 degrees, and
- wherein in the log-log graph, the amount of change in the threshold voltage when the time is 0.1 hours is smaller than 0.2 V.
A semiconductor device comprising:
- a transistor comprising:
- a first gate electrode over an insulating surface;
- an oxide semiconductor film overlapping with the first gate electrode;
- a first gate insulating film between the first gate electrode and the oxide semiconductor film;
- a pair of electrodes electrically connected to the oxide semiconductor film;
- a second gate insulating film over and in contact with a top surface of the oxide semiconductor film;
- and
- a second gate electrode overlapping with the oxide semiconductor film with the second gate insulating file positioned therebetween,
- wherein in a log-log graph of an amount of change in a threshold voltage of the transistor with respect to a time during which a load is applied to the transistor, a slope of a power approximate line of the amount of change in the threshold voltage with respect to the time is less than or equal to 0.5, and
- wherein in the log-log graph, the amount of change in the threshold voltage when the time is 0.1 hours is smaller than 0.2 V.
Dependencies are inferred from the claim text.