Catalyst Patents (Class 148/DIG16)
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Patent number: 6093587Abstract: A method of manufacturing a crystalline silicon film excellent in crystallinity. When using elements such as nickel as metal elements that promotes the crystallization of the amorphous silicon film, nickel is allowed to be contained in a solution repelled by the surface of the amorphous silicon film. Then, a part of the amorphous silicon film is removed, and the solution is held in only that part. In this way, the nickel elements are selectively introduced into a part of the amorphous silicon film, and a heat treatment is also conducted to allow crystal growth to proceed from that portion toward a direction parallel to a substrate.Type: GrantFiled: February 19, 1998Date of Patent: July 25, 2000Assignee: Semiconductor Energy Laboratory Co., Ltd.Inventor: Hisashi Ohtani
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Patent number: 5923962Abstract: 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.Type: GrantFiled: April 28, 1995Date of Patent: July 13, 1999Assignee: Semiconductor Energy Laboratory Co., Ltd.Inventors: Hisashi Ohtani, Akiharu Miyanaga, Takeshi Fukunaga, Hongyong Zhang
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Patent number: 5879974Abstract: Using a nickel element which is a metal element for promoting crystallized of silicon, an amorphous silicon film is crystallization into a crystalline silicon film, and then a thin film transistor (TFT) is produced by using the crystalline silicon film. That is, a solution containing nickel (for example nickel acetate solution) which promotes crystallization of silicon is applied in contact with a surface of an amorphous silicon through the spin coat method. Then the heating treatment is performed to crystallize the amorphous silicon film into the crystalline silicon film. In the state, nickel silicide components are removed using a solution containing hydrofluoric acid, hydrogen peroxide and water.Type: GrantFiled: August 1, 1996Date of Patent: March 9, 1999Assignee: Semiconductor Energy Laboratory Co., Ltd.Inventor: Shunpei Yamazaki
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Patent number: 5869362Abstract: Thin-film transistors each having a different characteristic are selectively formed on the same substrate. A silicon oxide film, an amorphous silicon film, a barrier film for preventing the diffusion of a nickel element and an oxide film containing a nickel element that promotes the crystallization of silicon are sequentially formed on a glass substrate. The oxide film containing the nickel element is patterned and subjected to a heat treatment, to thereby crystallize the amorphous silicon film under the oxide film whereas the amorphous silicon film from which the oxide film has been removed remains as it is. After the heat treatment has been conducted, a laser light is irradiated on those films. On the silicon film which has been crystallized by heating, a laser light is irradiated in a state where even a necessary energy density is attenuated after the laser light transmits the oxide film, thereby promoting the crystalline property.Type: GrantFiled: October 17, 1995Date of Patent: February 9, 1999Assignee: Semiconductor Energy Laboratory Co., Ltd.Inventor: Hisashi Ohtani
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Patent number: 5804473Abstract: A method for fabricating a thin film semiconductor device includes the steps of introducing, into an amorphous film of a semiconductor material, at least one metallic element that forms an intermetallic compound with the semiconductor material and at least one nonmetallic element selected from group VIa elements, group VIIa elements or nitrogen, and crystallizing the amorphous film, after introducing the metallic element and the nonmetallic element, by a thermal annealing process, to convert the amorphous film to a crystalline film.Type: GrantFiled: September 24, 1996Date of Patent: September 8, 1998Assignee: Fujitsu LimitedInventor: Yutaka Takizawa
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Patent number: 5773329Abstract: A method of low temperature and rapid silicon crystallization or rapid transformation of amorphous silicon to high quality polysilicon over a large area is disclosed using a pulsed rapid thermal annealing (PRTA) method and a metal seed layer. The PRTA method forms polysilicon thin film transistors (TFTs) with a high throughput, on low temperature and large area glass substrates. The PRTA method includes the steps of forming over a glass layer a tri-layer structure having a layer of amorphous silicon sandwiched between bottom and top dielectric layers; selectively etching the top dielectric layer to expose portions of the amorphous silicon layer; forming a metal seed layer over the exposed portions of the amorphous silicon layer; and pulsed rapid thermal annealing using successive pulses separated by rest periods to transform the amorphous silicon layer to a polysilicon layer. In an alternate PRTA method, instead of forming the tri-layer structure, a bi-layer structure is formded over the glass layer.Type: GrantFiled: July 24, 1996Date of Patent: June 30, 1998Assignee: International Business Machines CorporationInventor: Yue Kuo
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Patent number: 5712191Abstract: 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.Type: GrantFiled: September 8, 1995Date of Patent: January 27, 1998Assignee: Semiconductor Energy Laboratory Co., Ltd.Inventors: Setsuo Nakajima, Shunpei Yamazaki, Naoto Kusumoto, Satoshi Teramoto
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Patent number: 5696003Abstract: Into an amorphous silicon film, catalyst elements for accelerating the crystallization are introduced. After patterning the amorphous silicon films in which the catalyst elements have been introduced into an island pattern, a heat treatment for the crystallization is conducted. Thus, the introduced catalyst elements efficiently diffuse only inside the island-patterned amorphous silicon films. As a result, a high-quality crystalline silicon film, having the crystal growth direction aligned in one direction and having no grain boundaries, is obtained. Using the thus formed crystalline silicon film, semiconductor devices having a high performance and stable characteristics are fabricated efficiently over the entire substrate, irrespective of the size of the devices.Type: GrantFiled: December 16, 1994Date of Patent: December 9, 1997Assignee: Sharp Kabushiki KaishaInventors: Naoki Makita, Takashi Funai, Yoshitaka Yamamoto, Yasuhiro Mitani, Katsumi Nomura, Tadayoshi Miyamoto, Takamasa Kosai
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Patent number: 5693541Abstract: 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.Type: GrantFiled: August 23, 1995Date of Patent: December 2, 1997Assignee: Semiconductor Energy Laboratory Co., LtdInventors: Shunpei Yamazaki, Hongyong Zhang
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Patent number: 5643826Abstract: 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.Type: GrantFiled: October 25, 1994Date of Patent: July 1, 1997Assignee: Semiconductor Energy Laboratory Co., Ltd.Inventors: Hisashi Ohtani, Akiharu Miyanaga, Takeshi Fukunaga, Hongyong Zhang
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Method of manufacturing semiconductor device having different orientations of crystal channel growth
Patent number: 5614426Abstract: 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.Type: GrantFiled: August 23, 1995Date of Patent: March 25, 1997Assignee: Semiconductor Energy Laboratory Co., Ltd.Inventors: Fumiaki Funada, Tatsuo Morita, Hirohisa Tanaka, Hongyong Zhang, Toru Takayama -
Patent number: 5605846Abstract: A process for manufacturing a semiconductor device, particularly a thin film transistor, by using a crystalline silicon film having excellent characteristics. The process comprises forming a silicon nitride film and an amorphous silicon film in contact thereto, introducing a catalyst element capable of promoting the crystallization of the amorphous silicon film by heating the amorphous silicon film, thereby crystallizing at least a part of the amorphous silicon film, and accelerating the crystallization by irradiating the silicon film with a laser beam or intense light equivalent thereto.Type: GrantFiled: February 21, 1995Date of Patent: February 25, 1997Assignee: Semiconductor Energy Laboratory Co., Ltd.Inventors: Hisahi Ohtani, Akiharu Miyanaga, Hongyong Zhang, Naoaki Yamaguchi
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Patent number: 5595923Abstract: A substance containing a catalyst element is formed so as to closely contact with an amorphous silicon film, or a catalyst element is introduced into the amorphous silicon film. The amorphous silicon film is annealed at a temperature which is lower than a crystallization temperature of usual amorphous silicon, thereby selectively crystallizing the amorphous silicon film. The crystallized region is used as a crystalline silicon TFT which can be used in a peripheral driver circuit of an active matrix circuit. The region which remains amorphous is used as an amorphous silicon TFT which can be used in a pixel circuit. A relatively small amount of a catalyst element for promoting crystallization is added to an amorphous silicon film, and an annealing process is conducted at a temperature which is lower than the distortion temperature of a substrate, thereby crystallizing the amorphous silicon film.Type: GrantFiled: June 6, 1995Date of Patent: January 21, 1997Assignee: Semiconductor Energy Laboratory Co., Ltd.Inventors: Hongyong Zhang, Hideki Uochi, Toru Takayama, Yasuhiko Takemura, Mutsuo Yamamoto
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Patent number: 5585291Abstract: A method for manufacturing a semiconductor device having a crystalline silicon semiconductor layer comprises the steps of heat crystallizing an amorphous silicon semiconductor layer at a relatively low temperature because of the use of a crystallization promoting material such as Ni, Pd, Pt, Cu, Ag, Au, In, Sn, Pb, P, As, and Sb. The crystallization promoting material is introduced by mixing it within a liquid precursor material for forming silicon oxide and coating the precursor material onto the amorphous silicon film. Thus, it is possible to add the crystallization promoting material into the amorphous silicon film at a minimum density.Type: GrantFiled: November 29, 1994Date of Patent: December 17, 1996Assignee: Semiconductor Energy Laboratory Co., Ltd.Inventors: Hisashi Ohtani, Akiharu Miyanaga, Junichi Takeyama
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Patent number: 5580792Abstract: Method of fabricating a semiconductor device, such as a thin-film transistor, having improved characteristics and improved reliability. The method is initiated with formation of a thin amorphous silicon film on a substrate. A metallization layer containing at least one of nickel, iron, cobalt, and platinum is selectively formed on or under the amorphous silicon film so as to be in intimate contact with the silicon film, or these metal elements are added to the amorphous silicon film. The amorphous silicon film is thermally annealed to crystallize it. The surface of the obtained crystalline silicon film is etched to a depth of 20 to 200 .ANG., thus producing a clean surface. An insulating film is formed on the clean surface by CVD or physical vapor deposition. Gate electrodes are formed on the insulating film.Type: GrantFiled: February 13, 1995Date of Patent: December 3, 1996Assignee: Semiconductor Energy Laboratory Co., Ltd.Inventors: Hognyong Zhang, Hideki Uochi, Toru Takayama, Yasuhiko Takemura
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Patent number: 5550070Abstract: A method for producing a semiconductor film, includes the steps of: (a) forming an amorphous semiconductor film on a substrate having a surface with an insulating property; (b) introducing a material for accelerating crystallization of the amorphous semiconductor film into at least a part of the amorphous semiconductor film; (c) crystallizing the amorphous semiconductor film by heating to obtain a crystalline semiconductor film from the amorphous semiconductor film; and (d) oxidizing a surface of the crystalline semiconductor film to form a semiconductor oxide film containing a part of the material for accelerating the crystallization on the surface of the crystalline semiconductor film.Type: GrantFiled: December 16, 1994Date of Patent: August 27, 1996Assignee: Sharp Kabushiki KaishaInventors: Takashi Funai, Naoki Makita, Yoshitaka Yamamoto, Tatsuo Morita
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Patent number: 5529937Abstract: 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.Type: GrantFiled: July 20, 1994Date of Patent: June 25, 1996Assignee: Semiconductor Energy Laboratory Co., Ltd.Inventors: Hongyong Zhang, Hideto Ohnuma, Yasuhiko Takemura
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Patent number: 5492843Abstract: 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.Type: GrantFiled: July 29, 1994Date of Patent: February 20, 1996Assignee: Semiconductor Energy Laboratory Co., Ltd.Inventors: Hiroki Adachi, Yuugo Goto, Hongyong Zhang, Toru Takayama
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Patent number: 5488000Abstract: 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.Type: GrantFiled: June 14, 1994Date of Patent: January 30, 1996Assignee: Semiconductor Energy Laboratory Co., Ltd.Inventors: Hongyong Zhang, Satoshi Teramoto
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Patent number: 5426064Abstract: Method of fabricating a semiconductor device, such as a thin-film transistor, having improved characteristics and improved reliability. The method is initiated with formation of a thin amorphous silicon film on a substrate. A metallization layer containing at least one of nickel, iron, cobalt, and platinum is selectively formed on or under the amorphous silicon film so as to be in intimate contact with the silicon film, or these metal elements are added to the amorphous silicon film. The amorphous silicon film is thermally annealed to crystallize it. The surface of the obtained crystalline silicon film is etched to a depth of 20 to 200.ANG., thus producing a clean surface. An insulating film is formed on the clean surface by CVD or physical vapor deposition. Gate electrodes are formed on the insulating film.Type: GrantFiled: March 8, 1994Date of Patent: June 20, 1995Assignee: Semiconductor Energy Laboratory Co., Ltd.Inventors: Hognyong Zhang, Hideki Uochi, Toru Takayama, Yasuhiko Takemura
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Patent number: 5147827Abstract: A device such as a phototransistor, a photodiode, a laser diode or the like including a compound semiconductor coated with a stable passivation film to reduce leakage current is disclosed. The passivation film includes oxygen, a metallic element and constituent elements of the device, and the concentration of the elements included in the passivation film changes gradually through the interface between the passivation film and the device. Such a passivation film is formed by the oxidation or anodic oxidation of a device soaked in an aqueous solution of hydrogen oxide containing metallic ions such as Fe.sup.2+, Fe.sup.3+, Cu.sup.+, Cu.sup.2+, Co.sup.2+ or Cr.sup.2+ under the control of the temperature of the solution.Type: GrantFiled: June 6, 1991Date of Patent: September 15, 1992Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Toyoji Chino, Kenichi Matsuda, Shibata Jun
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Patent number: 5124278Abstract: The present invention addresses the use of metalorganic amines as metallic donor source compounds in reactive deposition applications. More specifically, the present invention addresses the use of the amino-substituted metallic donor source compounds M(NR.sub.2).sub.3-x H.sub.x, where R is organic, alkyl or fluoroalkyl, and x is less than or equal to 2, and M=As, Sb or P, in processes requiring deposition of the corresponding element. These uses include a number of different processes; the metalorganic vapor phase epitaxy of compound semiconductor material such as GaAs, InP, AlGaAs, etc.; doping of SiO.sub.2 or borosilicate based glasses to enhance the reflow properties of the glass; in-situ n-type doping of silicon epitaxial material; sourcing of arsenic or phosphorus for ion implantation; chemical beam epitaxy (or MOMBE); and diffusion doping into electronic materials such as silicon dioxide, silicon and polycrystalline silcon.Type: GrantFiled: September 21, 1990Date of Patent: June 23, 1992Assignee: Air Products and Chemicals, Inc.Inventors: David A. Bohling, Gregory T. Muhr, Sherri L. Bassner
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Patent number: 4806505Abstract: A method is provided for the oxidation of a silicon or gallium arsenide surface by depositing thereon a samarium or ytterbium overlayer prior to exposure of the surface to an oxidizing atmosphere.Type: GrantFiled: October 30, 1987Date of Patent: February 21, 1989Assignee: Regents of the University of MinnesotaInventor: Alfonso Franciosi
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Patent number: 4735921Abstract: Nitride layers are formed on semiconductor substrates utilizing alkali metals as catalysts. The surface of the semiconductor substrate first has a thin layer of an alkali metal deposited thereon and then is exposed to nitrogen from a nitrogen source at temperatures and pressures sufficient to grow a nitride layer, which will generally occur at lower temperatures than required for nitride formation by conventional processes. The surface is then annealed and the catalyst removed by heating at moderate temperatures, desorbing the catalyst and leaving a nitride layer on the surface of the substrate which is uncontaminated by the alkali metal catalyst. The process is particularly suited to the formation of nitride layers on silicon utilizing essentially a monolayer of the alkali metal such as sodium.Type: GrantFiled: May 29, 1987Date of Patent: April 5, 1988Inventor: Patrick Soukiassian
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Patent number: 4526629Abstract: One or more monolayers of cerium arrayed on the surface of a niobium metal acts as a catalyst to oxidation of the niobium at ambient temperature and results in a very thin, very high quality insulating layer which may be configured by patterning of the catalyst. Significant amounts of Nb.sub.2 O.sub.5 are formed at pressures as low as 6.6.times.10.sup.-6 Pa, promoted by the presence of the cerium. This catalytic activity is related to the trivalent to tetravalent valence change of the cerium during oxidation. The kinetics of Nb.sub.2 O.sub.5 formation beneath the oxidized cerium shows two stages:the first stage is fast growth limited by ion diffusion;the second stage is slow growth limited by electron tunneling.Other catalytic rare earths usable instead of cerium are terbium and praseodymium; other substrate materials usable instead of niobium are aluminum, hafnium, silicon and tantalum, or oxidizable alloys thereof.Type: GrantFiled: May 15, 1984Date of Patent: July 2, 1985Assignee: International Business Machines CorporationInventors: Ernst-Eberhard Latta, Maria Ronay