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: 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.

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 photoelectric conversion device taking the form of a thin film and having a substrate exhibiting poor thermal resistance. The device prevents thermal deformation which would normally be caused by local application of excessive heat to the substrate. The device has output terminals permitting the output from the device to be taken out. The output terminals are formed on the surface of the substrate opposite to the photoelectric conversion device. The device further includes electrical connector portions for electrically connecting the electrodes of the device with the output terminals. The present invention also provides a method of treating a substrate having poor thermal resistance with a plasma with a high throughput. The substrate is continuously supplied into a reaction chamber and treated with a plasma. This supply operation is carried out in such a way that the total length of the substrate existing in a plasma processing region formed by electrodes is longer than the length of the electrodes.

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: 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: The present invention relates to a display device. In particular, the display device of the present invention has a gate electrode over a substrate, the gate electrode has a lamination of a first conductive layer over the substrate and a second conductive layer on the first conductive layer; a semiconductor layer over the gate electrode with a gate insulating film interposed between; an insulating film in contact with a portion of the semiconductor layer; and at least one of source and drain electrodes formed in contact with a portion of the insulating film, where the first conductive layer does not have a tapered cross section, and the second conductive layer has a tapered cross section.

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 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 purpose of the invention is to provide a method for leveling a semiconductor layer without increasing the number and the complication of manufacturing processes as well as without deteriorating a crystal characteristic, and a method for leveling a surface of a semiconductor layer to stabilize an interface between the surface of the semiconductor layer and a gate insulating film, in order to achieve a TFT having a good characteristic.

Abstract: A liquid crystal display device in the prior art has been high in its manufacturing cost for the reason that TFTs have been fabricated using, at least, five photo-masks. 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: 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: There is disclosed a method of fabricating TFTs using a silicon film crystallized with the aid of nickel. The nickel is removed from the crystallized silicon film. The method starts with maintaining nickel in contact with the surface of an amorphous silicon film. Then, a heat treatment is performed to form a crystalline silicon film. At this time, nickel promotes the crystallization greatly, and nickel diffuses into the film. A mask is formed. A silicon film heavily doped with phosphorus is formed. Thereafter, a heat treatment is performed to move the nickel from the crystalline silicon film into the phosphorus-rich silicon film. This reduces the concentration of nickel in the crystalline silicon film.

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: There is provided a semiconductor device having TFTs whose thresholds can be controlled.

Abstract: A catalytic element for promoting crystallization of an amorphous silicon film is efficiently gettered to provide a highly reliable TFT, and an electro-optical device using the TFT and a method of manufacturing the electro-optical device are provided. The electro-optical device has an n-channel TFT and a p-channel TFT. A semiconductor layer of the p-channel TFT has a channel forming region (13), a region (11) containing an n-type impurity element and a p-type impurity element, and a region (12) containing only a p-type impurity element. In the p-channel TFT, a wiring line for electrically connecting the TFTs is connected to the region (12) containing only a p-type impurity element. The region containing an n-type impurity element in the p-channel TFT is narrower than a region doped with an n-type impurity element in a semiconductor layer of the n-channel TFT.

Abstract: A photoelectric conversion device taking the form of a thin film and having a substrate exhibiting poor thermal resistance. The device prevents thermal deformation which would normally be caused by local application of excessive heat to the substrate. The device has output terminals permitting the output from the device to be taken out. The output terminals are formed on the surface of the substrate opposite to the photoelectric conversion device. The device further includes electrical connector portions for electrically connecting the electrodes of the device with the output terminals. The present invention also provides a method of treating a substrate having poor thermal resistance with a plasma with a high throughput. The substrate is continuously supplied into a reaction chamber and treated with a plasma. This supply operation is carried out in such a way that the total length of the substrate existing in a plasma processing region formed by electrodes is longer than the length of the electrodes.

Abstract: A purpose of the invention is to provide a method for leveling a semiconductor layer without increasing the number and the complication of manufacturing processes as well as without deteriorating a crystal characteristic, and a method for leveling a surface of a semiconductor layer to stabilize an interface between the surface of the semiconductor layer and a gate insulating film, in order to achieve a TFT having a good characteristic. In an atmosphere of one kind or a plural kinds of gas selected from hydrogen or inert gas (nitrogen, argon, helium, neon, krypton and xenon), radiation with a laser beam in the first, second and third conditions is carried out in order, wherein the first condition laser beam is radiated for crystallizing a semiconductor film or improving a crystal characteristic; the second condition laser beam is radiated for eliminating an oxide film; and the third condition laser beam is radiated for leveling a surface of the crystallized semiconductor film.

Abstract: The present invention provides a semiconductor device and a method of manufacturing the same, the device being provided with a semiconductor circuit consisting of a semiconductor element that is capable of improving characteristics of a TFT and has uniform characteristics, the device and the method being provided by improving the interface between an active layer, in particular, a region for constructing a channel formation region and an insulating film.

Abstract: There is disclosed a method of fabricating TFTs using a silicon film crystallized with the aid of nickel. The nickel is removed from the crystallized silicon film. The method starts with maintaining nickel in contact with the surface of an amorphous silicon film. Then, a heat treatment is performed to form a crystalline silicon film. At this time, nickel promotes the crystallization greatly, and nickel diffuses into the film. A mask is formed. A silicon film heavily doped with phosphorus is formed. Thereafter, a heat treatment is performed to move the nickel from the crystalline silicon film into the phosphorus-rich silicon film. This reduces the concentration of nickel in the crystalline silicon film.