Abstract: A crystalline silicon thin film transistor having an LDD (lightly doped drain) structure and a process for fabricating the same, which comprises establishing an LDD by forming a gate insulating film and a gate electrode on an island-like semiconductor region and implanting thereafter impurities in a self-aligned manner to establish an LDD, anodically oxidizing the gate electrode and introducing impurities to form source and drain regions, partially or wholly removing the anodic oxide from the surface of the island-like semiconductor region to expose the LDD region, and irradiating a laser beam or an intense light having an intensity equivalent to that of the laser beam to activate the impurity region inclusive of the LDD.

Abstract: A semiconductor material and a method for forming the same, said semiconductor material having produced by a process comprising melting a noncrystal semiconductor film containing therein carbon, nitrogen, and oxygen each at a concentration of 5.times.10.sup.19 atoms.cm.sup.-3 or lower, preferably 1.times.10.sup.19 atoms.cm.sup.-3 or lower, by irradiating a laser beam or a high intensity light equivalent to a laser beam to said noncrystal semiconductor film, and then recrystallizing the thus molten amorphous silicon film. The present invention provides thin film semiconductors having high mobility at an excellent reproducibility, said semiconductor materials being useful for fabricating thin film semiconductor devices such as thin film transistors improved in device characteristics.

Abstract: An active matrix liquid crystal display having auxiliary capacitors. Two transparent conductive layers of ITO are formed on opposite sides of an insulating film. The first conductive layer forms pixel electrodes. The second transparent conductive film overlaps at least parts of the pixel electrodes via the insulating film to form the auxiliary capacitors without deteriorating the aperture ratio of the pixels.

Abstract: A high quality semiconductor device comprising at least a semiconductor film having a microcrystal structure is disclosed, wherein said semiconductor film has a lattice distortion therein and comprises crystal grains at an average diameter of 30 .ANG. to 4 .mu.m as viewed from the upper surface of said semiconductor film and contains oxygen impurity and concentration of said oxygen impurity is not higher than 7.times.10.sup.19 atoms.multidot.cm.sup.-3 at an inside position of said semiconductor film. Also is disclosed a method for fabricating semiconductor devices mentioned hereinbefore, which comprises depositing an amorphous semiconductor film containing oxygen impurity at a concentration not higher than 7.times.10.sup.19 atoms.multidot.cm.sup.-3 by sputtering from a semiconductor target containing oxygen impurity at a concentration not higher than 5.times.10.sup.18 atoms.multidot.cm.sup.

Abstract: A channel forming region of a thin-film transistor is covered with an electrode and wiring line that extends from a source line. As a result, the channel forming region is prevented from being illuminated with light coming from above the thin-film transistor, whereby the characteristics of the thin-film transistor can be made stable.

Abstract: A semiconductor device is manufactured by the use of a glass substrate which has previously been heated. An amorphous semiconductor layer is formed on the previously heated glass substrate and then crystallized by heat. By virtue of the previous heating, shrink of the glass substrate after the crystallization process is reduced. Accordingly, internal stress is not generated in the crystallized semiconductor layer. The semiconductor device thus manufactured is superior in electrical property.

Abstract: In an active matrix type liquid-crystal display device, in a peripheral circuit portion, there is arranged a TFT having a high mobility and capable of allowing a large amount of on-state current to flow. In a pixel portion, there is arranged a TFT having a small off-state current. These TFTs having different characteristics are constituted by using crystalline silicon film whose crystal has grown in a direction parallel with a substrate. That is, an angle formed between a crystal growing direction and a carrier moving direction are made different from each other, thereby to control a resistance imposed on the carriers when moving to determine the characteristics of the TFT. For example, when the crystal growing direction coincides with the carrier moving direction, high mobility can be given to the carriers. Further, when the crystal growing direction is arranged perpendicular to the carrier moving direction, the off-state current can be lowered.

Abstract: An amorphous silicon film is formed on a glass substrate by a CVD method, and a mask is formed of a silicon nitride film. Then, nickel is selectively doped into the amorphous silicon film by spin-coating solution containing nickel onto the amorphous silicon film. Thereafter, the amorphous silicon film is crystallized by a thermal treatment.

Abstract: A semiconductor device suitable for active-matrix addressed liquid crystal display device equipped with pixel electrodes and comprising a thin film transistor and a capacitor formed on the same insulation substrate, provided that said capacitor is formed from an oxide insulation film provided on the lower electrode and a silicon nitride film. Highly reliable thin film transistors and capacitors can be obtained.

Abstract: Method of forming a crystalline silicon film having excellent characteristics. An amorphous silicon film is formed on a substrate having an insulating surface. The amorphous film is thermally annealed at 400.degree.-620.degree. C., preferably at 520.degree.-620.degree. C., more preferably at 550.degree.-600.degree. C., for 1-12 hours. The silicon film is crystallized to a crystallinity of 0.1-99.9%, preferably 1-99%. Then, the silicon film is irradiated with UV laser radiation. Thus, the crystallinity of the silicon film is improved in a short time. Crystalline silicon films having uniform characteristics are obtained.

Abstract: A semiconductor circuit having a plurality of crystalline thin film transistors possessing different electrical characteristics which are formed on a substrate having an active matrix region and a driver circuit region. At least one first thin film transistor comprising a first crystalline silicon film is formed on the active matrix region of the substrate, while at least one second thin film transistor comprising a second crystalline silicon film is formed on the driver circuit region. The crystalline film of each of the first thin film transistors contains a catalyst element capable of promoting the crystallization of silicon at a higher concentration than the crystalline film of each of the second thin film transistors.

Abstract: An improved method of forming insulated gate field effect transistors is described. In accordance with the method, gate electrodes are formed from metal such as aluminum together with wirings electrically connecting the gate electrodes. The gate electrodes are anodic oxidized by dipping them as an anode in an electrolyte to form an oxide of the metal covering them. Since the connecting wirings are covered with a suitable organic film before the anodizing, no aluminum oxide is formed thereon so that it is easy to remove the connecting wiring by usual etching.

Abstract: A structure for reducing the OFF current of an active matrix display. In the active matrix display, plural TFTs are connected in series with each one pixel electrode. Of these TFTs connected in series, at least one TFT excluding the TFTs located at opposite ends is maintained in conduction. Alternatively, at least one capacitor is connected between the junction of the drain and source of each TFT connected in series and an AC grounded point. Thus, the amount of electric charge released from auxiliary capacitors during cutoff of the TFTs is reduced.

Abstract: In film forming of thin film semiconductors (TFTs), a gate electrode having an anodic-oxidizable material is formed on a substrate, and the surface of the gate electrode is oxidized by anodic oxidation in an electrolytic solution so that the surface of the gate electrode is coated with an insulating film. The doping is performed using the gate electrode and the anodic oxide film as a mask, to form a source and a drain region. Then, when the laminate is again dipped in an electrolytic solution, and a voltage is applied to the gate electrode so that a current curing produces in the laminate. During the current curing, a positive voltage is preferably applied to the gate electrode for N-channel TFTs and a negative voltage is preferably to the gate electrode for P-channel TFTs. After the doping, the source and the drain region is activated by laser annealing or the like, prior to the current curing.

Abstract: A method of manufacturing a semiconductor device comprises the steps of forming a first insulating film on a semiconductor layer, forming a gate electrode on the insulating film, pattering the first insulating film into a second insulating film so that a portion of the semiconductor layer is exposed while the second insulating film has extensions which extend beyond the side edges of the gate electrode, and performing ion introduction for forming impurity regions using the gate electrode and extensions of the gate insulating film as a mask. The condition of the ion introduction is varied in order to control the regions of the semiconductor layer to be added with the impurity and the concentration of the impurity therein.

Abstract: A method of fabricating silicon TFTs (thin-film transistors) is disclosed. The method comprises a crystallization step by laser irradiation effected after the completion of the device structure. First, amorphous silicon TFTs are fabricated. In each of the TFTs, the channel formation region, the source and drain regions are exposed to laser radiation illuminated from above or below the substrate. Then, the laser radiation is illuminated to crystallize and activate the channel formation region, and source and drain regions. After the completion of the device structure, various electrical characteristics of the TFTs are controlled. Also, the amorphous TFTs can be changed into polysilicon TFTs.

Abstract: A thin film transistor includes a crystallized amorphous silicon film having a gate insulating film and a gate electrode formed thereon. The device includes impurities implanted in a self-aligned manner and a catalyst that accelerates the crystallization of the silicon film. The catalyst is introduced in the silicon film by adhering a coating containing the catalyst element and annealing the resulting structure at a temperature lower than the deformation temperature of the substrate to activate the doped impurities. The catalyst element can also be incorporated into the silicon film by means of ion implantation and the like.

Abstract: A process for fabricating a highly stable and reliable semiconductor, comprising: coating the surface of an amorphous silicon film with a solution containing a catalyst element capable of accelerating the crystallization of the amorphous silicon film, and heat treating the amorphous silicon film thereafter to crystallize the film.

Abstract: Method of fabricating semiconductor devices such as thin-film transistors by annealing a substantially amorphous silicon film at a temperature either lower than normal crystallization temperature of amorphous silicon or lower than the glass transition point of the substrate so as to crystallize the silicon film. Islands, stripes, lines, or dots of nickel, iron, cobalt, or platinum, silicide, acetate, or nitrate of nickel, iron, cobalt, or platinum, film containing various salts, particles, or clusters containing at least one of nickel, iron, cobalt, and platinum are used as starting materials for crystallization. These materials are formed on or under the amorphous silicon film.

Abstract: Method of improving making contact with the source/drain regions of thin-film transistors. A substantially triangular insulator determines contacts with the source/drain regions by a self-aligning process. The width of this insulator can be determined without performing mask alignment. Furthermore, the width can be reduced. Therefore, the sheet resistance of the source/drain regions presents no serious problems.