A semiconductor device includes an extremely thin semiconductor-on-insulator substrate (ETSOI) having a base substrate, a thin semiconductor layer and a buried dielectric therebetween. A device channel is formed in the thin semiconductor layer. Source and drain regions are formed at opposing positions relative to the device channel. The source and drain regions include an n-type material deposited on the buried dielectric within a thickness of the thin semiconductor layer. A gate structure is formed over the device channel.

An array substrate includes a substrate, driving TFTs, and switch TFTs directly on the substrate. The driving TFT includes a buffer layer, a gate, a first gate insulator layer, a second gate insulator layer, and a metal oxide semiconductor layer stacked in that order on the substrate, and a source electrode and a drain electrode coupled to the metal oxide semiconductor layer. The switch TFT includes a buffer layer, a gate, a second gate insulator layer, and a metal oxide semiconductor layer stacked in that order on the substrate, and a source electrode and a drain electrode coupled to the metal oxide semiconductor layer.

A semiconductor device having a high aperture ratio and including a capacitor capable of increasing the charge capacity is provided. A semiconductor device includes a transistor over a substrate, a first light-transmitting conductive film over the substrate, an oxide insulating film covering the transistor and having an opening over the first light-transmitting conductive film, a nitride insulating film over the oxide insulating film and in contact with the first light-transmitting conductive film in the opening, a second light-transmitting conductive film connected to the transistor and having a depressed portion in the opening, and an organic resin film with which the depressed portion of the second light-transmitting conductive film is filled.

A thin-film transistor (TFT) switch includes a gate, a drain, a source, a semiconductor layer, and a fourth electrode. The drain is connected to a first signal. The gate is connected to a control signal to control the switch on or off. The source outputs the first signal when the switch turns on. The fourth electrode and the gate are respectively located at two sides of the semiconductor layer. The fourth electrode is conductive and is selectively coupled to different voltage levels, thereby reducing leakage current in a channel to improve switch characteristic when the switch turns off.

An object is to provide a semiconductor device with stable electric characteristics in which an oxide semiconductor is used. The impurity concentration in the oxide semiconductor layer is reduced in the following manner: a silicon oxide layer including many defects typified by dangling bonds is formed in contact with the oxide semiconductor layer, and an impurity such as hydrogen or moisture (a hydrogen atom or a compound including a hydrogen atom such as H.sub.2O) included in the oxide semiconductor layer is diffused into the silicon oxide layer. Further, a mixed region is provided between the oxide semiconductor layer and the silicon oxide layer. The mixed region includes oxygen, silicon, and at least one kind of metal element that is included in the oxide semiconductor.

The present disclosure provides an array substrate for a display device and a manufacturing method thereof. A transparent electrode pattern (ITO) may be formed between a source/drain metal pattern and a passivation layer located above the source/drain metal pattern, which are formed in a passivation hole area of a non-active area of the array substrate. Accordingly, it may be possible to prevent display failure caused by a delamination phenomenon or peel-off of a material of the passivation layer due to the lack of adhesion strength between a metal layer and the passivation layer in the passivation hole area.

The present invention provides a manufacture method of an oxide semiconductor TFT substrate and a structure thereof. The manufacture method of the dual gate oxide semiconductor TFT substrate utilizes the halftone mask to implement one photo process, which cannot only accomplish the patterning to the oxide semiconductor layer but also obtain the oxide conductor layer (53) with ion doping process; the method implements the patterning process to the bottom gate isolation layer (31) and the top gate isolation layer (32) at the same time with one photo process; the method implements patterning process to the second, third metal layers at the same time to obtain the first source (81), the first drain (82), the second source (83), the second drain (84), the first top gate (71) and the second top gate (72) with one photo process; the method implements patterning process to the second flat layer (9), the passivation layer (8) and the top gate isolation layer (32) at the same time with one photo process, to reduce the number of the photo processes to nine for effectively simplifying the manufacture process, raising the production efficiency and lowering the production cost.

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 thin-film transistor (TFT) switch includes a gate, a drain, a source, a semiconductor layer, and a fourth electrode. The drain is connected to a first signal. The gate is connected to a control signal to control the switch on or off. The source outputs the first signal when the switch turns on. The fourth electrode and the gate are respectively located at two sides of the semiconductor layer. The fourth electrode is conductive and is selectively coupled to different voltage levels, thereby reducing leakage current in a channel to improve switch characteristic when the switch turns off.

A method of making a display device includes, providing a substrate having a display area and a pad area in a periphery of the display area, the display area including a plurality of pixel regions; forming a thin film transistor having a channel layer on the substrate; arranging a gate link line and a first common voltage line to cross each other, and having a first insulation film be interposed therebetween; arranging a second common voltage line and a data link line to cross each other, and having second insulation film be interposed therebetween; disposing a first pattern on the first insulation film; and disposing a second pattern on the second insulation film, wherein the channel layer, the first pattern and the second pattern are formed of the same material.