Abstract:
A semiconductor device including an oxide semiconductor in which on-state current is high is provided. The semiconductor device includes a first transistor provided in a driver circuit portion and a second transistor provided in a pixel portion; the first transistor and the second transistor have different structures. Furthermore, the first transistor and the second transistor are transistors having a top-gate structure. In an oxide semiconductor film of each of the transistors, an impurity element is contained in regions which do not overlap with a gate electrode. The regions of the oxide semiconductor film which contain the impurity element function as low-resistance regions. Furthermore, the regions of the oxide semiconductor film which contain the impurity element are in contact with a film containing hydrogen. The first transistor provided in the driver circuit portion includes two gate electrodes between which the oxide semiconductor film is provided.
Abstract:
A change in electrical characteristics is inhibited and reliability is improved in a semiconductor device using a transistor including an oxide semiconductor. One embodiment of a semiconductor device including a transistor includes a gate electrode, first and second insulating films over the gate electrode, an oxide semiconductor film over the second insulating film, and source and drain electrodes electrically connected to the oxide semiconductor film. A third insulating film is provided over the transistor and a fourth insulating film is provided over the third insulating film. The third insulating film includes oxygen. The fourth insulating film includes nitrogen. The amount of oxygen released from the third insulating film is 1×1019/cm3 or more by thermal desorption spectroscopy, which is estimated as oxygen molecules. The amount of oxygen molecules released from the fourth insulating film is less than 1×1019/cm3.
Abstract:
A semiconductor device in which a decrease in the yield by electrostatic destruction can be prevented is provided. A scan line driver circuit for supplying a signal for selecting a plurality of pixels to a scan line includes a shift register for generating the signal. One conductive film functioning as respective gate electrodes of a plurality of transistors in the shift register is divided into a plurality of conductive films. The divided conductive films are electrically connected to each other by a conductive film which is formed in a layer different from the divided conductive films are formed. The plurality of transistors includes a transistor on an output side of the shift register.
Abstract:
The number of lithography processes is reduced and a high-definition display device is provided. The display device includes a pixel portion and a driver circuit for driving the pixel portion. The pixel portion includes a first transistor and a pixel electrode electrically connected to the first transistor. The driver circuit includes a second transistor and a connection portion. The second transistor includes a metal oxide film, first and second gate electrodes that face each other with the metal oxide film positioned therebetween, source and drain electrodes over and in contact with the metal oxide film, and a first wiring connecting the first and second gate electrodes. The connection portion includes a second wiring on the same surface as the first gate electrode, a third wiring on the same surface as the source electrode and the drain electrode, and a fourth wiring connecting the second wiring and the third wiring. The pixel electrode, the first wiring, and the fourth wiring are formed using the same layer.
Abstract:
A semiconductor device including a transistor is provided. The transistor includes a gate electrode, a first insulating film over the gate electrode, a second insulating film over the first insulating film, an oxide semiconductor film over the second insulating film, a source electrode and a drain electrode electrically connected to the oxide semiconductor film, a third insulating film over the source electrode, and a fourth insulating film over the drain electrode. A fifth insulating film including oxygen is provided over the transistor. The third insulating film includes a first portion, the fourth insulating film includes a second portion, and the fifth insulating film includes a third portion. The amount of oxygen molecules released from each of the first portion and the second portion is smaller than the amount of oxygen molecules released from the third portion when the amounts are measured by thermal desorption spectroscopy.
Abstract:
A transistor in which a change in characteristics is small is provided. A circuit, a semiconductor device, a display device, or an electronic device in which a change in characteristics of the transistor is small is provided. The transistor includes an oxide semiconductor; a channel region is formed in the oxide semiconductor; the channel region contains indium, an element M, and zinc; the element M is one or more selected from aluminum, gallium, yttrium, tin, boron, silicon, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, and magnesium; a gate insulator contains silicon and oxygen whose atomic number is 1.5 times or more as large as the atomic number of silicon; the carrier density of the channel region is higher than or equal to 1×109 cm−3 and lower than or equal to 5×1016 cm−3; and the energy gap of the channel region is higher than or equal to 2.7 eV and lower than or equal to 3.1 eV.
Abstract:
A method for manufacturing a semiconductor device has a first step including a step of forming an oxide semiconductor film, a second step including a step of forming a gate insulating film over the oxide semiconductor film and a step of forming a gate electrode over the gate insulating film, a third step including a step of forming a nitride insulating film over the oxide semiconductor film and the gate electrode, a fourth step including a step of forming an oxide insulating film over the nitride insulating film, a fifth step including a step of forming an opening in the nitride insulating film and the oxide insulating film, and a sixth step including a step of forming source and drain electrodes over the oxide insulating film so as to cover the opening. In the third step, the nitride insulating film is formed through at least two steps: plasma treatment and deposition treatment. The two steps are each performed at a temperature higher than or equal to 150° C. and lower than 300° C.
Abstract:
The semiconductor device includes a first transistor provided in a driver circuit portion and a second transistor provided in a pixel portion; the first transistor and the second transistor have different structures. In an oxide semiconductor film of each of the transistors, an impurity element is contained in regions which do not overlap with a gate electrode. The regions of the oxide semiconductor film which contain the impurity element function as low-resistance regions. Furthermore, the regions of the oxide semiconductor film which contain the impurity element are in contact with a film containing hydrogen. Furthermore, the first transistor provided in the driver circuit portion may include the oxide semiconductor film in which a first film and a second film are stacked, and the second transistor provided in the pixel portion may include the oxide semiconductor film which differs from the first film in the atomic ratio of metal elements.
Abstract:
A method for manufacturing a highly reliable semiconductor device is provided. The method includes the steps of: forming an oxide semiconductor film at a first temperature; processing the oxide semiconductor film into an island shape; not performing a process at a temperature higher than the first temperature, but depositing a material to be source and drain electrodes by a sputtering method; processing the material to form the source and drain electrodes; forming a protective insulating film, and then forming a first barrier film; adding excess oxygen or oxygen radicals to the protective insulating film through the first barrier film; performing heat treatment at a second temperature lower than 400° C. to diffuse the excess oxygen or oxygen radicals into the oxide semiconductor film; and removing part of the first barrier film and part of the protective insulating film by wet etching, and then forming a second barrier film.
Abstract:
To provide a semiconductor device including a transistor which includes an oxide semiconductor film and has excellent electrical characteristics. A semiconductor device includes a transistor including a first electrode, a first insulating film over the first electrode, an oxide semiconductor film over the first insulating film, a second insulating film over the oxide semiconductor film, and a second electrode over the second insulating film. The oxide semiconductor film includes a first oxide semiconductor film and a second oxide semiconductor film. The difference between energy at a conduction band minimum of the first oxide semiconductor film and energy at a conduction band minimum of the second oxide semiconductor film is greater than or equal to 0.2 eV. A rate of change in drain current per unit channel width relative to a drain voltage of 1 V can be less than or equal to 2%.