102results about How to "High field-effect mobility" patented technology

A protective circuit includes a non-linear element, which further includes a gate electrode, a gate insulating layer covering the gate electrode, a pair of first and second wiring layers whose end portions overlap with the gate electrode over the gate insulating layer and in which a conductive layer and a second oxide semiconductor layer are stacked, and a first oxide semiconductor layer which overlaps with at least the gate electrode and which is in contact with side face portions of the gate insulating layer and the conductive layer of the first wiring layer and the second wiring layer and a side face portion and a top face portion of the second oxide semiconductor layer. Over the gate insulating layer, oxide semiconductor layers with different properties are bonded to each other, whereby stable operation can be performed as compared with Schottky junction. Thus, the junction leakage can be decreased and the characteristics of the non-linear element can be improved.

A protective circuit includes a non-linear element, which includes a gate electrode, a gate insulating layer covering the gate electrode, a pair of first and second wiring layers whose end portions overlap with the gate electrode over the gate insulating layer and in which a second oxide semiconductor layer and a conductive layer are stacked, and a first oxide semiconductor layer which overlaps with at least the gate electrode and which is in contact with the gate insulating layer, side face portions and part of top face portions of the conductive layer and side face portions of the second oxide semiconductor layer in the first wiring layer and the second wiring layer. Over the gate insulating layer, oxide semiconductor layers with different properties are bonded to each other, whereby stable operation can be performed as compared with Schottky junction. Thus, the junction leakage can be decreased and the characteristics of the non-linear element can be improved.

A larger substrate can be used, and a transistor having a desirably high field-effect mobility can be manufactured through formation of an oxide semiconductor layer having a high degree of crystallinity, whereby a large-sized display device, a high-performance semiconductor device, or the like can be put into practical use. A first multi-component oxide semiconductor layer is formed over a substrate and a single-component oxide semiconductor layer is formed thereover; then, crystal growth is carried out from a surface to an inside by performing heat treatment at 500° C. to 1000° C. inclusive, preferably 550° C. to 750° C. inclusive so that a first multi-component oxide semiconductor layer including single crystal regions and a single-component oxide semiconductor layer including single crystal regions are formed; and a second multi-component oxide semiconductor layer including single crystal regions is stacked over the single-component oxide semiconductor layer including single crystal regions.

In order to form a structure in which an oxide semiconductor layer through which a carrier flows is not in contact with a gate insulating film, a buried channel structure in which the oxide semiconductor layer through which a carrier flows is away from the gate insulating film containing silicon is provided. Specifically, a buffer layer is provided between the gate insulating film and the oxide semiconductor layer. Both the oxide semiconductor layer and the buffer layer are formed using materials containing indium and another metal element. The composition of indium with respect to gallium contained in the oxide semiconductor layer is higher than the composition of indium with respect to gallium contained in the buffer layer. The buffer layer has a smaller thickness than the oxide semiconductor layer.

A protective circuit includes a non-linear element which includes a gate electrode, a gate insulating layer covering the gate electrode, a first oxide semiconductor layer overlapping with the gate electrode over the gate insulating layer, a channel protective layer overlapping with a channel formation region of the first oxide semiconductor layer, and a pair of a first wiring layer and a second wiring layer whose end portions overlap with the gate electrode over the channel protective layer and in which a conductive layer and a second oxide semiconductor layer are stacked. Over the gate insulating layer, oxide semiconductor layers with different properties are bonded to each other, whereby stable operation can be performed as compared with Schottky junction. Thus, the junction leakage can be reduced and the characteristics of the non-linear element can be improved.

A protective circuit includes a non-linear element which includes a gate electrode, a gate insulating layer covering the gate electrode, a first oxide semiconductor layer overlapping with the gate electrode over the gate insulating layer, and a first wiring layer and a second wiring layer whose end portions overlap with the gate electrode over the first oxide semiconductor layer and in which a conductive layer and a second oxide semiconductor layer are stacked. Over the gate insulating layer, oxide semiconductor layers with different properties are bonded to each other, whereby stable operation can be performed as compared with Schottky junction. Thus, the junction leakage can be reduced and the characteristics of the non-linear element can be improved.

In order to take advantage of the properties of a display device including an oxide semiconductor, a protective circuit and the like having appropriate structures and a small occupied area are necessary. The protective circuit is formed using a non-linear element which includes a gate insulating film covering a gate electrode; a first oxide semiconductor layer over the gate insulating film; a channel protective layer covering a region which overlaps with a channel formation region of the first oxide semiconductor layer; and a first wiring layer and a second wiring layer each of which is formed by stacking a conductive layer and a second oxide semiconductor layer and over the first oxide semiconductor layer. The gate electrode is connected to a scan line or a signal line, the first wiring layer or the second wiring layer is directly connected to the gate electrode.

An object is to manufacture a semiconductor device including an oxide semiconductor at low cost with high productivity in such a manner that a photolithography process is simplified by reducing the number of light-exposure masks. In a method for manufacturing a semiconductor device including a channel-etched inverted-stagger thin film transistor, an oxide semiconductor film and a conductive film are etched using a mask layer formed with the use of a multi-tone mask which is a light-exposure mask through which light is transmitted so as to have a plurality of intensities. The etching step is performed by wet etching in which an etching solution is used.

A display device including an oxide semiconductor, a protective circuit and the like having appropriate structures and a small occupied area is necessary. The protective circuit is formed using a non-linear element which includes a gate insulating film covering a gate electrode; a first oxide semiconductor layer which is over the gate insulating layer and overlaps with the gate electrode; and a first wiring layer and a second wiring layer each of which is formed by stacking a conductive layer and a second oxide semiconductor layer and whose end portions are over the first oxide semiconductor layer and overlap with the gate electrode. The gate electrode of the non-linear element is connected to a scan line or a signal line, the first wiring layer or the second wiring layer of the non-linear element is directly connected to the gate electrode layer so as to apply potential of the gate electrode.

A light emitting device and an element substrate which are capable of suppressing variations in the luminance intensity of a light emitting element among pixels due to characteristic variations of a driving transistor without suppressing off-current of a switching transistor low and increasing storage capacity of a capacitor. According to the invention, a depletion mode transistor is used as a driving transistor. The gate of the driving transistor is fixed in its potential or connected to the source or drain thereof to operate in a saturation region with a constant current flow. A current controlling transistor which operates in a linear region is connected in series to the driving transistor, and a video signal for transmitting a light emission or non-emission of a pixel is inputted to the gate of the current controlling transistor through a switching transistor.

One of factors that increase the contact resistance at the interface between a first semiconductor layer where a channel is formed and source and drain electrode layers is a film with high electric resistance formed by dust or impurity contamination of a surface of a metal material serving as the source and drain electrode layers. As a solution, a first protective layer and a second protective layer including a second semiconductor having a conductivity that is less than or equal to that of the first semiconductor layer is stacked successively over source and drain electrode layers without exposed to air, the stack of films is used for the source and drain electrode layers.

One embodiment of the present invention provides a highly reliably display device in which a high mobility is achieved in an oxide semiconductor. A first oxide component is formed over a base component. Crystal growth proceeds from a surface toward an inside of the first oxide component by a first heat treatment, so that a first oxide crystal component is formed in contact with at least part of the base component. A second oxide component is formed over the first oxide crystal component. Crystal growth is performed by a second heat treatment using the first oxide crystal component as a seed, so that a second oxide crystal component is formed. Thus, a stacked oxide material is formed. A transistor with a high mobility is formed using the stacked oxide material and a driver circuit is formed using the transistor.

An electrically conducting organic compound comprising a condensed polycyclic aromatic compound containing from 8 to 14 condensed rings and being solubilized in a solvent by the introduction of a functional group into any condensed ring of the compound. The electrically conducting organic compound is used as a constituent element in the production of electronic devices.

A light emitting device and an element substrate which are capable of suppressing variations in luminance intensity of a light emitting element among pixels due to characteristic variations of a driving transistor without suppressing off-current of a switching transistor low and increasing storage capacity of a capacitor. A gate potential of a driving transistor is connected to a first scan line or a second scan line, and the driving transistor operates in a saturation region. A current controlling transistor which operates in a linear region is connected in series to the driving transistor. A video signal which transmits a light emission or non-emission of a pixel is input to the gate of the current controlling transistor through a switching transistor.

The protective circuit is formed using a non-linear element which includes a gate insulating film covering a gate electrode; a first wiring layer and a second wiring layer which are over the gate insulating film and whose end portions overlap with the gate electrode; and an oxide semiconductor layer which is over the gate electrode and in contact with the gate insulating film and the end portions of the first wiring layer and the second wiring layer. The gate electrode of the non-linear element and a scan line or a signal line is included in a wiring, the first or second wiring layer of the non-linear element is directly connected to the wiring so as to apply the potential of the gate electrode.