E-book reader
AssigneeSemiconductor Energy Laboratory Co., Ltd.
InventorsShunpei YAMAZAKI, Atsushi UMEZAKI
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Abstract
An e-book reader including a display panel having a thin film transistor with stable electrical characteristics is provided. Alternatively, an e-book reader capable of holding images for a long time is provided. Alternatively, a high-resolution e-book reader is provided. Alternatively, an e-book reader with low power consumption is provided. Display on the display panel of the e-book reader is controlled by a thin film transistor whose channel formation region is formed using an oxide semiconductor which is an intrinsic or substantially intrinsic semiconductor by removal of an impurity that might be an electron donor in the oxide semiconductor and has a larger energy gap than a silicon semiconductor.
Claims7
(canceled)
A semiconductor device comprising:
- a gate electrode;
- a first gate insulating film over the gate electrode;
- a second gate insulating film over the first gate insulating film;
- an oxide semiconductor film over the second gate insulating film;
- a source electrode over the oxide semiconductor film;
- a drain electrode over the oxide semiconductor film;
- an oxide insulating film over the oxide semiconductor film, the source electrode and the drain electrode;
- a protective insulating film over the oxide insulating film;
- a planarization insulating film over the protective insulating film;
- and
- a pixel electrode over the planarization insulating film,
- wherein the first gate insulating film comprises nitrogen and silicon,
- wherein the second gate insulating film comprises oxygen and silicon,
- wherein the oxide insulating film comprises a region in contact with the oxide semiconductor film,
- wherein the protective insulating film comprises nitrogen and silicon,
- wherein the pixel electrode is electrically connected to a transistor including the oxide semiconductor film, and
- wherein an off-state current of the transistor having a channel width of one micrometer is 1×10−17 A or less.
Dependencies are inferred from the claim text.