Abstract: A method for manufacturing a semiconductor device such as a thin film transistor using a crystal silicon film is provided. The crystal silicon film is obtained by selectively forming films, particles or clusters containing nickel, iron, cobalt, ruthenium, rhodium, paradium, osmium, iridium, platinum, scandium, titanium, vanadium, chrome, manganese, copper, zinc, gold, silver or silicide thereof in a form of island, line, stripe, dot or film on or under an amorphous silicon film and using them as a starting point, by advancing its crystallization by annealing at a temperature lower than a normal crystallization temperature of an amorphous silicon. A transistor whose leak current is low and a transistor in which a mobility is high are obtained in the same time in structuring a dynamic circuit having a thin film transistor by selectively forming a cover film on a semiconductor layer which is to become an active layer of the transistor and by thermally crystallizing it thereafter.

Abstract: An improved method of forming a semiconductor device on a glass substrate is described. The method comprises forming a semiconductor film on a glass substrate, heating the semiconductor film by means of a heater to a predetermined temperature, exposing the semiconductor film to pulsed laser light after the semiconductor film has been heated to the predetermined temperature by the heating step. The thermal shock due to sharp temperature change is lessened by the pre-heating step. The width of the pulsed laser light is greater than the height when a cross section is taken perpendicular to a length.

Abstract: An improved method for manufacturing an insulated gate field effect transistor is described. The method comprises the steps of forming a semiconductor film on an insulating substrate, forming a gate insulating film on said semiconductor film, forming a gate electrode on said gate insulating film with said gate insulating film inbetween, anoding said gate electrode in order to coat an external surface of said gate electrode with an oxide film thereof and applying a negative or positive voltage to said gate electrode with respect to said semiconductor film. Lattice defects and interfacial states caused by the application of a positive voltage during the anoding are effectively eliminated by the negative voltage application.

Abstract: A method for manufacturing a thin film transistor having a crystalline silicon layer as an active layer comprises the steps of disposing a solution containing a catalyst for promoting a crystallization of silicon in contact with an amorphous silicon film, crystallizing the amorphous silicon at a relatively low temperature and then improving the crystallinity by irradiating the film with a laser light. The concentration of the catalyst in the crystallized silicon film can be controlled by controlling the concentration of the catalyst in the solution.

Abstract: Method of processing, e.g., laser annealing, objects such as semiconductor devices with pulsed lasers with high production yield and high reproducibility so as to obtain good characteristics stably. The pulse width of the irradiated pulse beam is set to more than 30 nsec to stabilize the processing. To achieve a pulse width exceeding 30 nsec, plural lasers are connected in series or in parallel and excited successively.

Abstract: After a pattern is transferred on silicon film crystallized by annealing, the silicon film is annealed by radiation of intense rays for a short time. Especially, in the crystallizing process by annealing, an element which promotes crystallization such as nickel is doped therein. The area not crystallized by annealing is also crystallized by radiation of intense rays and a condensed silicon film is formed. After a metal element which promotes crystallization is doped, annealing by light for a short time is performed by radiating intense rays onto the silicon film crystallized by annealing in an atmosphere containing halide. After the surface of the silicon film is oxidized by heating or by radiating intense rays in a halogenated atmosphere and an oxide film is formed on the silicon film, the oxide film is then etched. As a result, nickel in the silicon film is removed.

Abstract: A gate-insulated thin film transistor is disclosed. One improvement is that the thin film transistor is formed on a substrate through a blocking layer in between so that it is possible to prevent the transistor from being contaminated with impurities such as alkali ions which exist in the substrate. Also, a halogen is added to either or both of the blocking layer and a gate insulator of the transistor in order that impurities such as alkaline ions, dangling bonds and the like can be neutralized, therefore, the reliability of the device is improved.

Abstract: An insulated-gate field-effect transistor adapted to be used in an active-matrix liquid-crystal display. The channel length, or the distance between the source region and the drain region, is made larger than the length of the gate electrode taken in the longitudinal direction of the channel. Offset regions are formed in the channel region on the sides of the source and drain regions. No or very weak electric field is applied to these offset regions from the gate electrode.

Abstract: In a thin film transistor (TFT), a mask is formed on a gate electrode, and a porous anodic oxide is formed in both sides of the gate electrode using a relatively low voltage. A barrier anodic oxide is formed between the gate electrode and the porous anodic oxide and on the gate electrode using a relatively high voltage. A gate insulating film is etched using the barrier anodic oxide as a mask. The porous anodic oxide is selectively etched after etching barrier anodic oxide, to obtain a region of an active layer on which the gate insulating film is formed and the other region of the active layer on which the gate insulating film is not formed. An element including at least one of oxygen, nitrogen and carbon is introduced into the region of the active layer at high concentration in comparison with a concentration of the other region of the active layer. Further, N- or P-type impurity is introduced into the active layer.

Abstract: Method of fabricating a semiconductor device. A glass substrate such as Corning 7059 is used as a substrate. A bottom film is formed. Then, the substrate is annealed above the strain point of the glass substrate. The substrate is then slowly cooled below the strain point. Thereafter, a silicon film is formed, and a TFT is formed. The aforementioned anneal and slow cooling reduce shrinkage of the substrate created in later thermal treatment steps. This makes it easy to perform mask alignments. Furthermore, defects due to misalignment of masks are reduced, and the production yield is enhanced. In another method, a glass substrate made of Corning 7059 is also used as a substrate. The substrate is annealed above the strain point. Then, the substrate is rapidly cooled below the strain point. Thereafter, a bottom film is formed, and a TFT is fabricated. The aforementioned anneal and slow cooling reduce shrinkage of the substrate created in later thermal treatment steps.

Abstract: Method of fabricating TFTs starts with forming a nickel film selectively on a bottom layer which is formed on a substrate. An amorphous silicon film is formed on the nickel film and heated to crystallize it. The crystallized film is irradiated with infrared light to anneal it. Thus, a crystalline silicon film having excellent crystailinity is obtained. TFTs are built, using this crystalline silicon film.

Abstract: A wiring formed on a substrate is oxidized and the oxide is used as a mask for forming source and drain impurity regions of a transistor, or as a material for insulating wirings from each other, or as a dielectric of a capacitor. Thickness of the oxide is determined depending on purpose of the oxide. In a transistor adapted to be used in an active-matrix liquid-crystal display, the channel length, or the distance between the source region and the drain region, is made larger than the length of the gate electrode taken in the longitudinal direction of the channel. Offset regions are formed in the channel region on the sides of the source and drain regions. No or very weak electric field is applied to these offset regions from the gate electrode.

Abstract: Nickel is introduced to a peripheral circuit section and a picture element section on an amorphous silicon film to crystallize them. After forming gate electrodes and others, a source, drain and channel are formed by doping impurities, and laser is irradiated to improve the crystallization. After that, electrodes/wires are formed. Thereby an active matrix type liquid crystal display whose thin film transistors (TFT) in the peripheral circuit section are composed of the crystalline silicon film crystal-grown in the direction parallel to the flow of carriers and whose TFTs in the picture element section are composed of the crystalline silicon film crystal-grown in the direction vertical to the flow of carriers can be obtained.

Abstract: In a thin-film insulated gate type field effect transistor having a metal gate in which the surface of the gate electrode is subjected to anodic oxidation, a silicon nitride film is provided so as to be interposed between the gate eiectrode and the gate insulating film to prevent invasion of movable ions into a channel, and also to prevent the breakdown of the gate insulating film due to a potential difference between the gate electrode and the channel region. By coating a specific portion of the gate eiectrode with metal material such as chrome or the like for the anodic oxidation, and then removing only the metal material such as chrome or the like together with the anodic oxide of the metal material such as chrome or the like, an exposed portion of metal gate (e.g. aluminum) is formed, and an upper wiring is connected to the exposed portion.

Abstract: A process for laser processing an article, which comprises: heating the intended article to be doped with an impurity to a temperature not higher than the melting point thereof, said article being made from a material selected from a semiconductor, a metal, an insulator, and a combination thereof; and irradiating a laser beam to the article in a reactive gas atmosphere containing said impurity, thereby allowing the impurity to physically or chemically diffuse into, combine with, or intrude into said article.

Abstract: A method for manufacturing a semiconductor device such as a thin film transistor using a crystal silicon film is provided. The crystal silicon film is obtained by selectively forming films, particles or clusters containing nickel, iron, cobalt, ruthenium, rhodium, paradium, osmium, iridium, platinum, scandium, titanium, vanadium, chrome, manganese, copper, zinc, gold, silver or silicide thereof in a form of island, line, stripe, dot or film on or under an amorphous silicon film and using them as a starting point, by advancing its crystallization by annealing at a temperature lower than a normal crystallization temperature of an amorphous silicon. A transistor whose leak current is low and a transistor in which a mobility is high are obtained in the same time in structuring a dynamic circuit having a thin film transistor by selectively forming a cover film on a semiconductor layer which is to become an active layer of the transistor and by thermally crystallizing it thereafter.

Abstract: A process for crystallizing an amorphous semiconductor by irradiating a laser beam thereto, which comprises thermally annealing the amorphous semiconductor prior to the crystallization thereof in vacuum or in an inactive gas atmosphere at a temperature not higher than the crystallization temperature of the amorphous semiconductor, and then irradiating a laser beam to the thermally annealed amorphous semiconductor in vacuum or in an inactive gas atmosphere to crystallize the amorphous semiconductor. The process provides a uniform polycrystalline silicon film having high crystallinity, which has less dependence on the energy density of the laser beam which is irradiated thereto for crystallization, and hence useful for thin film devices such as insulated gate field effect transistors.

Abstract: There is disclosed a method for forming a semiconductor film having a high electrical conductivity on a substrate at a low temperature below 200.degree. C. with high productivity by sputtering. For example, the sputtering process is carried out within an inert atmosphere consisting of an inert gas such as argon and hydrogen. The substrate is electrically insulated (floating) from the surroundings. The distance between the substrate and a target is set to a large value. Preferably, the ratio of the partial pressure of the hydrogen to the total pressure is 30 % or more. The target consists of a semiconductor doped with an impurity that imparts one conductivity type to the semiconductor, in the case where a semiconductor film containing an impurity that imparts the conductivity type to the semiconductor film is formed on the substrate. This impurity is for example a group III or V element.

Abstract: A semiconductor material and a method for forming the same, the semiconductor material having fabricated by a process comprising irradiating a laser beam or a high intensity light equivalent to a laser beam to an amorphous silicon film containing therein carbon, nitrogen, and oxygen each at a concentration of 5.times.10.sup.19 atoms.multidot.cm.sup.-3 or lower, preferably 1.times.10.sup.19 atoms.multidot.cm.sup.-3 or lower, without melting the amorphous silicon film. The present invention provides thin film semiconductors having high mobility at an excellent reproducibility, the semiconductor materials being useful for fabricating compact thin film semiconductor devices such as thin film transistors improved in device characteristics.

Abstract: A gate-insulated thin film transistor is disclosed. One improvement is that the thin film transistor is formed on a substrate through a blocking layer in between so that it is possible to prevent the transistor from being contaminated with impurities such as alkali ions which exist in the substrate. Also, a halogen is added to either or both of the blocking layer and a gate insulator of the transistor in order that impurities such as alkaline ions, dangling bonds and the like can be neutralized, therefore, the reliability of the device is improved.