Abstract: There is provided a semiconductor device having TFTs whose thresholds can be controlled. There is provided a semiconductor device including a plurality of TFTs having a back gate electrode, a first gate insulation film, a semiconductor active layer a second gate insulation film and a gate electrode, which are formed on a substrate, wherein an arbitrary voltage is applied to the back gate electrode.

Abstract: This invention improves TFT characteristics by making an interface between an active layer, especially a region forming a channel formation region and an insulating film excellent, and provides a semiconductor device provided with a semiconductor circuit made of a semiconductor element having uniform characteristics and a method of fabricating the same. In order to achieve the object, a gate wiring line is formed on a substrate or an under film, a gate insulating film, an initial semiconductor film, and an insulating film are formed into a laminate without exposing them to the atmosphere, and after the initial semiconductor film is crystallized by irradiation of infrared light or ultraviolet light (laser light) through the insulating film, patterning is carried out to obtain an active layer and a protection film each having a desired shape, and then, a resist mask is used to fabricate the semiconductor device provided with an LDD structure.

Abstract: After crystallization of a semiconductor film is performed by irradiating first laser light (energy density of 400 to 500 mJ/cm2) in an atmosphere containing oxygen, an oxide film formed by irradiating the first laser light is removed. It is next performed to irradiate second laser light under an atmosphere that does not contain oxygen (at a higher energy density than that of the first laser light irradiation), thus to increase the flatness of the semiconductor film.

Abstract: A method of producing a semiconductor device which removes catalyst elements from a silicon-containing semiconductor film while maintaining the advantage of low temperature process is provided. The method comprises the steps of: forming an amorphous semiconductor film containing silicon on a glass substrate to crystallize it by using a catalyst element; selectively introducing into the amorphous semiconductor film an impurity belonging to Group 15 to form gettering regions and regions to be gettered; and causing the catalyst element in the silicon film to move to the gettering regions by heat treatment. Through the gettering process, the crystalline silicon film can be obtained in which the concentration of nickel contained therein is sufficiently reduced.

Abstract: To provide a technology for fabricating a bottom gate type TFT by steps having high mass production performance, an insulating film whose major component is silicon is formed on an active layer, the insulating film is patterned and openings are formed at portions thereof constituting source and drain regions at later steps, a resist is provided right above a portion for forming a channel forming region at later steps, a step of adding an impurity is carried out and in this case, the patterned insulating film is utilized as a doping mask.

Abstract: A method of fabricating a driver circuit for use with a passive matrix or active matrix electrooptical display device such as a liquid crystal display. The driver circuit occupies less space than heretofore. A circuit (stick crystal) having a length substantially equal to the length of one side of the matrix of the display device is used as the driver circuit. The circuit is bonded to one substrate of the display device, and then the terminals of the circuit are connected with the terminals of the display device. Subsequently, the substrate of the driver circuit is removed. This makes the configuration of the circuit much simpler than the configuration of the circuit heretofore required by the TAB method or COG method, because conducting lines are not laid in a complex manner. The driver circuit can be formed on a large-area substrate such as a glass substrate. The display device can be formed on a lightweight material having a high shock resistance such as a plastic substrate.

Abstract: Subjected to obtain a crystalline TFT which simultaneously prevents increase of OFF current and deterioration of ON current. A gate electrode of a crystalline TFT is comprised of a first gate electrode and a second gate electrode formed in contact with the first gate electrode and a gate insulating film. LDD region is formed by using the first gate electrode as a mask, and a source region and a drain region are formed by using the second gate electrode as a mask. By removing a portion of the second gate electrode, a structure in which a region where LDD region and the second gate electrode overlap with a gate insulating film interposed therebetween, and a region where LDD region and the second gate electrode do not overlap, is obtained.

Abstract: An object of the present invention is to provide a TFT of new structure in which the gate electrode overlaps with the LDD region and a TFT of such structure in which the gate electrode does not overlap with the LDD region. The TFT is made from crystalline semiconductor film and is highly reliable. The TFT of crystalline semiconductor film has the gate electrode formed from a first gate electrode 113 and a second gate electrode in close contact with said first gate electrode and gate insulating film. The LDD is formed by ion doping using said first gate electrode as a mask, and the source-drain region is formed using said second gate electrode as a mask. After that the second gate electrode in the desired region is selectively removed. In this way it is possible to form LDD region which overlaps with the second gate electrode.

Abstract: In a liquid crystal display device, a first substrate includes electrical wirings and a semiconductor integrated circuit which has TFTs and is connected electrically to the electrical wirings, and a second substrate includes a transparent conductive film on a surface thereof. A surface of the first substrate on which the electrical wirings are formed is opposite to the transparent conductive film on the second substrate. The semiconductor integrated circuit has substantially the same length as one side of a display screen (i.e., a matrix circuit) of the display device and is obtained by peeling it from another substrate and then forming it on the first substrate. Also, in a liquid crystal display device, a first substrate includes a matrix circuit and a peripheral driver circuit, and a second substrate is opposite to the first substrate, includes a matrix circuit and a peripheral driver circuit and has at least a size corresponding to the matrix circuit and the peripheral driver circuit.

Abstract: After crystallization of a semiconductor film is performed by irradiating first laser light (energy density of 400 to 500 mJ/cm2) in an atmosphere containing oxygen, an oxide film formed by irradiating the first laser light is removed. It is next performed to irradiate second laser light under an atmosphere that does not contain oxygen (at a higher energy density than that of the first laser light irradiation), thus to increase the flatness of the semiconductor film.

Abstract: There are provided a substrate of a semiconductor device and a fabrication method thereof which allow to suppress impurity from turning around from a glass or quartz substrate in fabrication steps of a TFT. An insulating film is deposited so as to surround the glass substrate by means of reduced pressure thermal CVD. It allows to suppress the impurity from infiltrating from the glass substrate to an active region of the TFT in the later process.

Abstract: [Problem] A liquid crystal display device in the prior art has been high in its manufactural cost for the reason that TFTs have been fabricated using, at least, five photo-masks. [Means for Resolution]A liquid crystal display device which includes a pixel TFT portion having an n-channel TFT of inverse stagger type, and a retention capacitor, can be realized by three photolithographic steps in such a way that a pixel electrode 119, a source region 117 and a drain region 116 are formed by a third photo-mask.

Abstract: A semiconductor device that uses a high reliability TFT structure is provided. The gate electrode of an n-channel type TFT is formed by a first gate electrode and a second gate electrode that covers the first gate electrode. LDD regions have portions that overlap the second gate electrode through a gate insulating film, and portions that do not overlap. As a result, the TFT can be prevented from degradation in an ON state, and it is possible to reduce the leak current in an OFF state.

Abstract: In a plasma film forming apparatus, two first electrodes 51 connected to a power source 4 and two grounded second electrodes 52 are arranged in the order of the second electrode 52, the first electrode 51, the first electrode 51 and the second electrode 52. A first flow passage 50a formed between the central first electrodes 51 allows a raw material gas (first gas) for being formed into a film to pass therethrough. A plasma discharge space 50b of a second flow passage formed between the first and second electrodes 51, 52 on the both sides allows an excitable gas (second gas) to pass therethrough, which excitable gas is exited by plasma such that the raw material can be formed into a film, but that the excitable gas itself is merely excited but not formed into a film. Those gases are converged at a crossing part 20c between the first and second flow passages and blown off via a common blowoff passage 25a.

Abstract: Disclosed is a technique of improving the heat resistance of the aluminum gate electrode in bottom-gate-type TFT of which the active layer is made of a crystalline silicon film. A pattern of a laminate of a titanium film 102 and an aluminum film 103 is formed on a glass substrate 101. The pattern is to give a gate electrode 100. Then, the titanium film 102 is side-etched. Next, the layered substrate is heated to thereby intentionally form hillocks and whiskers-on the surface of the aluminum pattern 103. Next, the aluminum pattern 103 acting as an anode is subjected to anodic oxidation to form an oxide film 105 thereon. The anodic oxidation extends to the lower edge of the aluminum pattern 103, at which the titanium layer was side-etched. Next, a gate-insulating film 106 and an amorphous silicon film are formed. A mask is formed over the pattern, which is to give -the gate electrode, and then a nickel acetate solution is applied to the layered structure.

Abstract: This invention improves TFT characteristics by making an interface between an active layer, especially a region forming a channel formation region and an insulating film excellent, and provides a semiconductor device provided with a semiconductor circuit made of a semiconductor element having uniform characteristics and a method of fabricating the same. In order to achieve the object, a gate wiring line is formed on a substrate or an under film, a gate insulating film, an initial semiconductor film, and an insulating film are formed into a laminate without exposing them to the atmosphere, and after the initial semiconductor film is crystallized by irradiation of infrared light or ultraviolet light (laser light) through the insulating film, patterning is carried out to obtain an active layer and a protection film each having a desired shape, and then, a resist mask is used to fabricate the semiconductor device provided with an LDD structure.

Abstract: In a liquid crystal display device, a first substrate includes electrical wirings and a semiconductor integrated circuit which has TFTs and is connected electrically to the electrical wirings, and a second substrate includes a transparent conductive film on a surface thereof. A surface of the first substrate on which the electrical wirings are formed is opposite to the transparent conductive film on the second substrate. The semiconductor integrated circuit has substantially the same length as one side of a display screen (i.e., a matrix circuit) of the display device and is obtained by peeling it from another substrate and then forming it on the first substrate. Also, in a liquid crystal display device, a first substrate includes a matrix circuit and a peripheral driver circuit, and a second substrate is opposite to the first substrate, includes a matrix circuit and a peripheral driver circuit and has at least a size corresponding to the matrix circuit and the peripheral driver circuit.

Abstract: A laser-irradiation method which comprises a process for fabricating a semiconductor device, comprising: a first step of forming a thin film amorphous semiconductor on a substrate having an insulating surface; a second step of modifying the thin film amorphous semiconductor into a crystalline thin film semiconductor by irradiating a pulse-type linear light and/or by applying a heat treatment; a third step of implanting an impurity element which imparts a one conductive type to the crystalline thin film semiconductor; and a fourth step of activating the impurity element by irradiating a pulse-type linear light and/or by applying a heat treatment; wherein the peak value, the peak width at half height, and the threshold width of the laser energy in the second and the fourth steps above are each distributed within a range of approximately ±3% of the standard value. Also claimed is a laser irradiation device which realizes the method above.

Abstract: To manufacture a liquid crystal display device with high thin film transistor accumulation, high productivity and high reliability by efficiently gettering a catalyst element, which promotes crystallization of an amorphous silicon film, from a channel region. In order to solve the above object, a step of providing a gettering sink on the outside of a p-channel thin film transistor region, and a step of removing a region provided on the outside of the thin film transistor region within the region where the catalyst element is gettered in a self-aligning manner by a source wiring or a drain wiring, are combined.

Abstract: There is provided a semiconductor device including a semiconductor circuit formed by semiconductor elements having an LDD structure which has high reproducibility, improves the stability of TFTs and provides high productivity and a method for manufacturing the same.