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: 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: 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: 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: 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: 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: 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: 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: In producing a thin film transistor, after an amorphous silicon film is formed on a substrate, a nickel silicide layer is formed by spin coating with a solution (nickel acetate solution) containing nickel as the metal element which accelerates (promotes) the crystallization of silicon and by heat treating. The nickel silicide layer is selectively patterned to form island-like nickel silicide layer. The amorphous silicon film is patterned. A laser light is irradiated while moving the laser, so that crystal growth occurs from the region in which the nickel silicide layer is formed and a region equivalent to a single crystal (a monodomain region) is obtained.

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: A crystalline semiconductor film having crystal grains of large grain size or crystal grains in which the position and the size are controlled is formed to manufacture a TFT, whereby a semiconductor device that enables a high-speed operation is realized. First, a reflecting member is provided on a rear surface side of a substrate on which a semiconductor film is formed (semiconductor film substrate). When a front surface side of the semiconductor film substrate is irradiated with a laser beam that penetrates the semiconductor film substrate, the laser beam is reflected by the reflecting member to irradiate the semiconductor film from the rear surface side. With this method, an effective energy density is raised in the semiconductor film, and an output time is made long. Thus, the cooling rate of the semiconductor film is made gentle and crystal grains of large grain size are formed.

Abstract: A technique for manufacturing TFTs having little dispersion in their electrical characteristics is provided. Contamination of a semiconductor film is reduced by performing oxidation processing having an organic matter removing effect, forming a clean oxide film, after removing a natural oxide film formed on a semiconductor film surface. TFTs having little dispersion in their electrical characteristics can be obtained by using the semiconductor film thus obtained in active layers of the TFTs, and the electrical properties can be improved. In addition, deterioration in productivity and throughput can be reduced to a minimum by using a semiconductor manufacturing apparatus of the present invention.

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: 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: A method for manufacturing a semiconductor device including forming a gate electrode over a substrate; forming a pate insulating film over the pate electrode and over the substrate; forming a semiconductor film on the gate insulating film; providing the semiconductor film with a metal element; crystallizing the semiconductor film provided with the metal element; doping an element which is used for gettering into a portion of the crystallized semiconductor film; and heating the crystallized semiconductor film whereby the metal element contained in a channel region of the semiconductor film is gettered by the portion.

Abstract: Protrusions called ridges are formed on the surface of a crystalline semiconductor film formed by a laser crystallization method or the like. A heat absorbing layer are formed below a semiconductor film. When the semiconductor film is crystallized by laser, a temperature difference is produced between a semiconductor film 1010 positioned above a heat absorbing layer 1011 and a semiconductor film 1013 of the other region to produce a difference in thermal expansion at the boundary of the outside end 1015 of the heat absorbing layer. This difference produces a strain to form a surface wave. The surface wave starting at the outer periphery of the heat absorbing layer is formed in the vicinity of the heat absorbing layer. When the semiconductor layer is solidified after it is melted, the protrusions of the surface wave remain as protrusions after the semiconductor film is solidified.

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: There are provided a substrate of a semiconductor device and a fabrication method thereof which 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 suppresses the impurity from infiltrating from the glass substrate to an active region of the TFT in the later process.

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. In order to achieve the object, the design of a second mask is appropriately determined in accordance with requirements associated with the circuit configuration to make it possible to form a desired LDD region on both sides or one side of the channel formation region of a TFT.

Abstract: Protrusions called ridges are formed on the surface of a crystalline semiconductor film formed by a laser crystallization method or the like. A heat absorbing layer are formed below a semiconductor film. When the semiconductor film is crystallized by laser, a temperature difference is produced between a semiconductor film 1010 positioned above a heat absorbing layer 1011 and a semiconductor film 1013 of the other region to produce a difference in thermal expansion at the boundary of the outside end 1015 of the heat absorbing layer. This difference produces a strain to form a surface wave. The surface wave starting at the outer periphery of the heat absorbing layer is formed in the vicinity of the heat absorbing layer. When the semiconductor layer is solidified after it is melted, the protrusions of the surface wave remain as protrusions after the semiconductor film is solidified.