Introduction Of Nondopant Into Semiconductor Layer Patents (Class 438/162)
  • Patent number: 6121076
    Abstract: A silicon film provided on a blocking film 102 on a substrate 101 is made amorphous by doping Si+, and in a heat-annealing process, crystallization is started in parallel to a substrate from an area 100 where nickel serving as a crystallization-promoting catalyst is introduced.
    Type: Grant
    Filed: August 4, 1997
    Date of Patent: September 19, 2000
    Assignee: Semiconductor Energy Laboratory Co., Ltd.
    Inventors: Hongyong Zhang, Toru Takayama, Yasuhiko Takemura
  • Patent number: 6093934
    Abstract: Nickel is selectively held in contact with a particular region of an amorphous silicon film. Crystal growth parallel with a substrate is effected by performing a heat treatment. A thermal oxidation film is formed on the silicon film by performing a heat treatment in an oxidizing atmosphere containing a halogen element. During this step, in the silicon film, impurities included such as oxygen or chlorine, are segregated with extending along the crystal growth, the crystallinity is improved, and the gettering of nickel element proceeds. A thin-film transistor is formed so that the direction connecting source and drain regions coincides with the above crystal growth direction. As a result, a TFT having superior characteristics such as a mobility larger than 200 cm.sup.2 /Vs and an S value smaller than 100 mV/dec. can be obtained.
    Type: Grant
    Filed: January 17, 1997
    Date of Patent: July 25, 2000
    Assignee: Semiconductor Energy Laboratory Co., Ltd.
    Inventors: Shunpei Yamazaki, Satoshi Teramoto, Jun Koyama, Yasushi Ogata, Masahiko Hayakawa, Mitsuaki Osame, Hisashi Ohtani, Toshiji Hamatani
  • Patent number: 6093586
    Abstract: To enable radiating an optimum energy beam depending upon the structure of a substrate (whether a metallic film is formed or not) when an amorphous semiconductor film is crystallized and uniformly crystallizing the overall film, first, a photoresist film and the area of an N.sup.+ doped amorphous silicon film on the photoresist film are selectively removed by a lift-off method. Hereby, the amorphous silicon film is thicker in an area except an area over a metallic film (a gate electrode) than in the area over the metallic film. In this state, a laser beam is radiated. The N.sup.+ doped amorphous silicon film and an amorphous silicon film are melted by radiating a laser beam and afterward, melted areas are crystallized by cooling them to room temperature.
    Type: Grant
    Filed: July 29, 1997
    Date of Patent: July 25, 2000
    Assignee: Sony Corporation
    Inventors: Dharam Pal Gosain, Jonathan Westwater, Miyako Nakagoe, Setsuo Usui
  • Patent number: 6090646
    Abstract: A silicon film provided on a blocking film 102 on a substrate 101 is made amorphous by doping Si+, and in a heat-annealing process, crystallization is started in parallel to a substrate from an area 100 where nickel serving as a crystallization-promoting catalyst is introduced.
    Type: Grant
    Filed: October 2, 1997
    Date of Patent: July 18, 2000
    Assignee: Semiconductor Energy Laboratory Co., Ltd.
    Inventors: Hongyong Zhang, Yasuhiko Takemura, Toru Takayama
  • Patent number: 6087206
    Abstract: In a top-gate type thin film transistor including a polycrystalline silicon pattern having a channel region, a source region and a drain region on a substrate, a gate electrode via a gate insulating layer on the polycrystalline silicon layer, an insulating layer thereon, and metal electrodes coupled to the source region and the drain region, dangling bonds of silicon of the channel region at an interface with the gate insulating layer and dangling bonds of silicon of a part of the drain region are combined with hydrogen.
    Type: Grant
    Filed: November 6, 1998
    Date of Patent: July 11, 2000
    Assignee: NEC Corporation
    Inventor: Koji Hamada
  • Patent number: 6083780
    Abstract: A semiconductor device and a method of fabricating such a semiconductor device in which a silicon nitride film constituting a protective film for ion implantation is used for improving the device structure in order that conversion of a metal film into a silicide for reducing the resistance of a shallow-junction diffused layer may not be prevented by the knock-on phenomenon of oxygen, thereby reduce the fabrication cost. A silicon nitride film, which is used as a protective film for ion implantation into a substrate and a gate polysilicon, is processed into side walls of the gate polysilicon thereby to omit the step of forming side walls by a silicon oxide film. Further, in the case where boron is diffused into the gate polysilicon, boron diffusion is suppressed by nitrogen knock-on, thereby preventing boron from going through the gate oxide film.
    Type: Grant
    Filed: April 22, 1997
    Date of Patent: July 4, 2000
    Assignee: United Microelectronics Corporation
    Inventor: Hiroyasu Yasuda
  • Patent number: 6071763
    Abstract: A method of fabricating layered integrated circuits on a silicon wafer utilizes the buried oxide insulating layer of a SOI structure for isolating junction devices such as diodes, well resistors, N.sup.30 resistors, P.sup.30 resistors, and bipolar junction transistors from MOS transistors. Consequently, junction devices are formed in the semiconductor substrate below the buried oxide insulation layer while the MOS transistors are formed in an epitaxial silicon layer above the buried oxide insulation layer. Furthermore, the MOS transistors located above the epitaxial silicon layer are isolated from each other by trench isolation structures. Since this invention provides a method of fabricating a layered integrated circuit structure whose devices can be stacked on top of each other in separate layers, the degree of integration for each unit area of wafer surface is increased.
    Type: Grant
    Filed: July 7, 1998
    Date of Patent: June 6, 2000
    Assignee: United Microelectronics Corp.
    Inventor: Jia-Sheng Lee
  • Patent number: 6057182
    Abstract: A method of making a liquid crystal display which has a layer of polysilicon on a surface of a substrate, a gate of a conductive material over and insulated from a portion of the polysilicon layer, a layer of an insulating material over the gate, and a metal layer on the insulating layer. The method includes forming a layer of an insulating material over the metal layer and then subjecting the device to a plasma containing hydrogen to diffuse the hydrogen through the insulating layers and the metal layer into the polysilicon layer.
    Type: Grant
    Filed: September 5, 1997
    Date of Patent: May 2, 2000
    Assignee: Sarnoff Corporation
    Inventors: Lawrence Alan Goodman, Grzegorz Kaganowicz, Lawrence Keith White, Harry Louis Pinch, Ronald Keith Smeltzer
  • Patent number: 6051494
    Abstract: A semiconductor device in which parasitic resistance of source/drain regions can be reduced than the parasitic resistance of the drain region, and manufacturing method thereof, can be obtained. In the semiconductor device, inactivating ions are implanted only to the source region of the semiconductor layer, so as to damage the crystal near the surface of the semiconductor layer, whereby siliciding reaction is promoted. Therefore, in the source region, a titanium silicide film which is thicker can be formed.
    Type: Grant
    Filed: May 13, 1997
    Date of Patent: April 18, 2000
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Toshiaki Iwamatsu, Yasuo Inoue, Yasuo Yamaguchi, Tadashi Nishimura
  • Patent number: 6051452
    Abstract: A silicon oxide layer serving as an insulation layer is formed on a p-type semiconductor substrate. An n.sup.+ -type source and drain regions are formed on the p-type substrate 110 with a spacing therebetween. A channel region is interposed between the source and drain regions. A silicon oxide layer serving as an insulation layer is formed on the channel region. A gate terminal is formed on the silicon oxide layer. High-concentration p-type regions are formed in the p-type semiconductor substrate under the source and drain regions, respectively.
    Type: Grant
    Filed: January 6, 1998
    Date of Patent: April 18, 2000
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Naoyuki Shigyo, Toshiyuki Enda
  • Patent number: 6019796
    Abstract: A method of producing an improved thin film transistor structure is provided having no source/gate or drain/gate overlap. A laser-assisted doping technique is applied to fabricate such transistors. A radiation filter is employed, which is transparent to light at the photolithography wavelength, but reflective or opaque at the laser wavelength. Eliminating source/gate and drain/gate overlap significantly reduces or eliminates parasitic capacitance and feed-through voltage between source and gate. Short-channel a-Si:H thin film transistors may be obtained having high field effect mobilities. Improved pixel performance and pixel-to-pixel uniformity is provided.
    Type: Grant
    Filed: October 29, 1997
    Date of Patent: February 1, 2000
    Assignee: Xerox Corporation
    Inventors: Ping Mei, Rene A. Lujan, James B. Boyce, Christopher L. Chua, Michael G. Hack
  • Patent number: 6010923
    Abstract: There is provided a semiconductor device in which a semiconductor layer and a gate electrode are formed with a gate insulating layer between then and in which a region of the semiconductor layer opposite to the gate electrode is used as a channel region. On the semiconductor layer, an insulating protection film and an amorphous semiconductor layer are successively formed. The protection film covers at least the channel region of the amorphous semiconductor layer, and annealing is applied to the amorphous semiconductor layer, thereby converting the amorphous semiconductor layer into the polycrystal semiconductor layer. A portion to be the channel region of the amorphous semiconductor layer is covered by the protection film. Therefore, even when exposed to the atmosphere due to annealing, surface contamination can be prevented and a semiconductor device having satisfactory characteristics can be obtained. A thickness d of the protection film is set to be nearly ".lambda./4n" for a wavelength .lambda.
    Type: Grant
    Filed: March 27, 1998
    Date of Patent: January 4, 2000
    Assignee: Sanyo Electric Co., Ltd.
    Inventor: Yushi Jinno
  • Patent number: 5994164
    Abstract: The present invention is generally related to controllably modifying or tailoring the structure of crystalline films to adjust and enhance the material properties of the film, such as optical, mechanical and electrical properties. Crystalline films generally refer to microcrystalline (.mu.c) film, nanocrystalline (nc) film, polycrystalline (poly-c) film, and other crystallized films. The present invention provides a method for controllably obtaining desired grain sizes (or crystal sizes) in crystalline films and for controllably providing a predominance of grains sizes in a predetermined range to adjust and enhance the optical absorption properties of the crystalline film. The present invention also provide a method for controlling the mechanical properties, e.g., stress formation levels, during crystallization of at least a portion of the precursor film. Through control of the stress formation levels, it is possible to controllably adjust and enhance the electrical properties (e.g.
    Type: Grant
    Filed: March 18, 1998
    Date of Patent: November 30, 1999
    Assignee: The Penn State Research Foundation
    Inventors: Stephen J. Fonash, A. Kaan Kalkan
  • Patent number: 5989963
    Abstract: A method of manufacturing a semiconductor device with a steep retrograde profile. The threshold voltage adjust dopant layer and the punchthrough prevent dopant layer are formed in the substrate. All surface capping layers are removed from the active device regions and, the semiconductor device is placed in a chamber and a high vacuum is established after which an inert atmosphere is introduced into the chamber. The anneal to repair the damage to the lattice and to activate the dopant ions in the dopant layers is done in the inert atmosphere with the surface of the substrate maintained clean, that is, free from a capping oxide or other layer formed on the surface of the substrate.
    Type: Grant
    Filed: July 21, 1997
    Date of Patent: November 23, 1999
    Assignee: Advanced Micro Devices, Inc.
    Inventors: Scott D. Luning, David C. Greenlaw, Jonathan Fewkes
  • Patent number: 5985703
    Abstract: A thin film transistor includes, a) a thin film source region; b) a thin film drain region; c) a polycrystalline thin film channel region intermediate the thin film source region and the thin film drain region; d) a transistor gate and gate dielectric operatively positioned adjacent the thin film channel region; and e) the thin film channel region comprising at least an inner layer, an outer layer and a middle layer sandwiched between the inner layer and the outer layer, the inner layer and the outer layer comprising polycrystalline silicon and having respective energy bandgaps, the middle sandwich layer comprising a polycrystalline material and having a lower energy bandgap than either of the inner and outer layers. Alternately, the channel region is homogeneous, comprising germanium or an alloy of polycrystalline silicon and germanium.
    Type: Grant
    Filed: May 13, 1996
    Date of Patent: November 16, 1999
    Inventor: Sanjay Banerjee
  • Patent number: 5981318
    Abstract: A field-effect transistor structure wherein a single patterned thin film semiconductor layer: is monocrystalline, and epitaxially matched to and dielectrically isolated from an underlying body region, in channel locations; and is polycrystalline in source/drain locations which abut said channel locations.
    Type: Grant
    Filed: December 18, 1997
    Date of Patent: November 9, 1999
    Assignee: STMicroelectronics, Inc.
    Inventor: Richard A. Blanchard
  • Patent number: 5976919
    Abstract: A large area semiconductor element can be manufactured with high productivity, which has low electric resistance at the boundary face of a metal and a semiconductor and has excellent characteristics and reliability. A manufacturing apparatus comprises an ion irradiation means for simultaneously irradiating hydrogen ions and ions containing an element serving as a dopant of a semiconductor to a semiconductor film or a substrate in an atmosphere under reduced pressure, and a film forming means which forms a thin film or a heat treatment means which conducts a heat treatment without exposing a sample to an air. When a sample having an a-Si:H thin film is brought into a sample preparation chamber by opening a gate valve, the chamber is exhausted to have the inside pressure of 10.sup.2 to 10.sup.-3 Pa. Then, the sample is forwarded to an ion irradiation chamber from the sample preparation chamber via an intermediate chamber of which the pressure is maintained in the range of 10.sup.-3 to 10.sup.
    Type: Grant
    Filed: August 1, 1997
    Date of Patent: November 2, 1999
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Takashi Hirao, Akihisa Yoshida, Masatoshi Kitagawa
  • Patent number: 5972782
    Abstract: Ultrasound treatment (UST) of poly-Si thin films on glass substrates is disclosed, for improving properties of such thin films for uses such in thin-film transistor applications. Hydrogenated films subjected to UST showed a strong decrease of the sheet resistivity. UST improves the electrical homogeneity of polycrystalline silicon as confirmed by spatially resolved surface photovoltage mapping. Spatially resolved photoluminescence and contact potential difference mapping confirmed that UST effect is grain boundary related. Studies of hydrogenated thin-film transistors demonstrated remarkable UST induced improvement in transistor characteristics, especially, a reduction of leakage current by as much as one order of magnitude and a shift of the threshold voltage. All these effects are believed to result from UST enhanced hydrogenation of dangling bonds at grain boundaries in polycrystalline silicon films.
    Type: Grant
    Filed: October 9, 1996
    Date of Patent: October 26, 1999
    Inventor: Serguei Ostapenko
  • Patent number: 5969407
    Abstract: An amorphized implant is performed to retard diffusion of ions in the source and drain regions. By retarding the diffusion of ions in these regions, a shallower junction is advantageously created in the silicon regions of the wafer. A slight degradation in leakage current is obtained if the amorphized implant is performed on both the source and the drain sides of a transistor. However, since the source region is a low voltage region with a very shallow junction, MOSFETs in both n-channel and p-channel regions are formed with improved performance and reliability.A method of fabricating an integrated circuit includes forming a gate electrode over a semiconductor substrate, forming a source mask extending over the drain region of the semiconductor substrate, and implanting an implant species into the source region of the semiconductor substrate to form an amorphous implant layer of the semiconductor substrate.
    Type: Grant
    Filed: March 30, 1998
    Date of Patent: October 19, 1999
    Assignee: Advanced Micro Devices, Inc.
    Inventors: Mark I. Gardner, H. Jim Fulford, Jr., Derick J. Wristers
  • Patent number: 5970366
    Abstract: In a method of forming a silicon substrate, a gettering film is formed on a bottom surface of a silicon substrate. An oxygen ion implantation into a top surface of the silicon substrate is carried out at a substrate temperature in the range of 400.degree. C.-700.degree. C. The gettering film is removed from the silicon substrate. The silicon substrate is subjected to a heat treatment at a temperature of not less than 1300.degree. C. for causing a reaction of oxygen and silicon to form a silicon oxide film in the silicon substrate after the gettering film is removed.
    Type: Grant
    Filed: July 16, 1997
    Date of Patent: October 19, 1999
    Assignee: NEC Corporation
    Inventor: Kensuke Okonogi
  • Patent number: 5970384
    Abstract: Silicon oxide films which are good as gate insulation films are formed by subjecting a silicon oxide film which has been formed on an active layer comprising a silicon film by means of a PVD method or CVD method to a heat treatment at 300-700.degree. C. in a dinitrogen monoxide atmosphere, or in an NH.sub.3 or N.sub.2 H.sub.4 atmosphere, while irradiating with ultraviolet light, reducing the hydrogen and carbon contents in the silicon oxide film and introducing nitrogen into the boundary with the silicon film in particular. Furthermore, silicon oxide films which are good as gate insulating films have been formed by subjecting silicon oxide films which have been formed on an active layer comprising a silicon film by means of a PVD method or CVD method to a heat treatment at 300-700.degree. C. in an N.sub.2 O atmosphere (or hydrogen nitride atmosphere) while irradiating with ultraviolet light, and then carrying out a heat treatment at 300-700.degree. C. in a hydrogen nitride atmosphere (N.sub.
    Type: Grant
    Filed: August 2, 1995
    Date of Patent: October 19, 1999
    Assignee: Semiconductor Energy Laboratory Co., Ltd.
    Inventors: Shunpei Yamazaki, Yasuhiko Takemura, Mitsunori Sakama, Tomohiko Sato, Satoshi Teramoto, Shigefumi Sakai
  • Patent number: 5956597
    Abstract: According to a preferred embodiment of the present invention, a stress-reducing region formed on a wafer allows standard bulk CMOS (non-SOI) devices and SOI devices to be reliably fabricated on the same wafer. The high-stress interface that typically exists between the SOI device regions and the non-SOI device regions is transferred to a region where the high-stress will be reduced and relaxed. Typically, this means that the high-stress interface will be fabricated so as to lie over a region of the wafer similar to Shallow Trench Isolation (STI) regions. In addition, by using another preferred embodiment of the present invention, a coplanar wafer surface can be maintained for a wafer which includes both bulk CMOS devices and SOI devices. This is accomplished by etching the silicon wafer in the SOI device regions prior to the oxygen implantation so that the surface of the area between the stress interface regions is lower than the overall surface of the remainder of the wafer. Then, when the SiO.sub.
    Type: Grant
    Filed: September 15, 1997
    Date of Patent: September 21, 1999
    Assignee: International Business Machines Corporation
    Inventors: Toshiharu Furukawa, Mark C. Hakey, Steven J. Holmes, David V. Horak, Paul A. Rabidoux
  • Patent number: 5953595
    Abstract: The manufacturing processes can be simplified and the reliability can be improved. A method of processing a thin film includes a first process of selectively forming a resist pattern on a ground surface, a second process of forming a thin film on the ground surface and a surface of the resist pattern, and a third process of removing the resist pattern to selectively remove the thin film deposited on the former, i.e., carrying out the lift-off, thereby the thin film process for a desired pattern being carried out.
    Type: Grant
    Filed: September 27, 1996
    Date of Patent: September 14, 1999
    Assignee: Sony Corporation
    Inventors: Dharam Pal Gosain, Jonathan Westwater, Miyako Nakagoe, Setsuo Usui
  • Patent number: 5946560
    Abstract: A crystalline silicon thin film transistor having an LDD (lightly doped drain) structure and a process for fabricating the same, which comprises introducing a catalyst element for accelerating crystallization at a concentration of 1.times.10.sup.15 cm.sup.-3 or more but less than 2.times.10.sup.19 cm.sup.-3 to the impurity region in an amorphous silicon film, crystallizing the amorphous film thereafter, and after forming gate electrode and gate insulating film, implanting an impurity in a self-aligned manner to establish an LDD structure.
    Type: Grant
    Filed: July 10, 1997
    Date of Patent: August 31, 1999
    Assignee: Semiconductor Energy Laboratory Co., Ltd.
    Inventors: Hideki Uochi, Yasuhiko Takemura
  • Patent number: 5946562
    Abstract: Polysilicon thin film transistors (TFTs) are formed on glass substrates by selectively etching a dielectric layer to expose portions of an amorphous silicon layer in areas of the substrate occupied by the thin film transistor forming a metal seed layer over the exposed portions of the amorphous silicon layer; and selectively annealing the exposed areas with a laser beam to transform the amorphous silicon layer to a polysilicon layer.
    Type: Grant
    Filed: July 31, 1997
    Date of Patent: August 31, 1999
    Assignee: International Business Machines Corporation
    Inventor: Yue Kuo
  • Patent number: 5936291
    Abstract: The thin film transistor of this invention is formed on a substrate and includes an active layer and a first insulating film and a second insulating film sandwiching the active layer, wherein the overall polarity of fixed charges contained in the first insulating film is the reverse of the overall polarity of fixed charges contained in the second insulating film.
    Type: Grant
    Filed: January 30, 1998
    Date of Patent: August 10, 1999
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Naoki Makita, Muneyuki Motohashi, Hidehiko Yamashita, Hideo Izawa
  • Patent number: 5923967
    Abstract: In the method for fabricating a TFT utilizing a polycrystalline silicon thin film as an intrinsic semiconductor region, a polycrystalline silicon thin film, a gate insulating film and a gate electrode are formed in this order on a substrate. An anodic oxide film is formed on a surface of the gate electrode for providing an offset thereto. The polycrystalline silicon thin film is then doped with hydrogen using the gate electrode having the offset as a mask to form hydrogen containing regions. The heating treatment for about one hour or more in a range of about 300.degree. C. to about 450.degree. C. is performed for hydrogenation of the polycrystalline silicon film. Impurities such as P or B are introduced to form contact regions (n.sup.+ regions or p.sup.+ regions) and then the introduced impurities are activated by irradiation of an excimer laser. An interlayer insulating film, source/drain electrodes and a protection film are further formed, thereby completing the TFT.
    Type: Grant
    Filed: November 15, 1996
    Date of Patent: July 13, 1999
    Assignee: Sharp Kabushiki Kaisha
    Inventor: Tomohiko Yamamoto
  • Patent number: 5923966
    Abstract: A laser processing apparatus provides a heating chamber, a chamber for laser light irradiation and a robot arm, wherein a temperature of a substrate on which a silicon film to be irradiated with laser light is formed is heated to 450 to 750.degree. C. in the heating chamber followed by irradiating the silicon film with laser light so that a silicon film having a single crystal or a silicon film that can be regarded as the single crystal can be obtained.
    Type: Grant
    Filed: July 20, 1995
    Date of Patent: July 13, 1999
    Assignee: Semiconductor Energy Laboratory Co., Ltd.
    Inventors: Satoshi Teramoto, Hisashi Ohtani, Akiharu Miyanaga, Toshiji Hamatani, Shunpei Yamazaki
  • Patent number: 5904513
    Abstract: A thin film transistor includes: a) a thin film transistor layer comprising a source region, a channel region and a drain region; the thin film transistor layer further comprising a drain offset region positioned between the drain region and the channel region; b) the channel region being substantially polycrystalline and having a first average crystalline grain size; and c) the drain offset region being substantially polycrystalline and having a second average crystalline grain size, the second average crystalline grain size being larger than the first average crystalline grain size. A method for forming such a construction using polycrystalline materials, preferably polysilicon, and an amorphizing silicon implant with subsequent recrystallization is also disclosed.
    Type: Grant
    Filed: July 1, 1996
    Date of Patent: May 18, 1999
    Assignee: Micron Technology, Inc.
    Inventors: Shubneesh Batra, Monte Manning, Sanjay Banerjee, John Damiano, Jr.
  • Patent number: 5904510
    Abstract: A cellular insulated gate bipolar transistor ("IGBT") device employs increased concentration in the active region between spaced bases to a depth greater than the depth of the base regions. The implant dose which is the source of the increased concentration is about 3.5.times.10.sup.12 atoms per centimeter squared and is driven for about 10 hours at 1175.degree. C. Lifetime is reduced by an increased radiation dose to reduce switching loss without reducing breakdown voltage or increasing forward voltage drop above previous levels. The increased concentration region permits a reduction in the spacing between bases and provides a region of low localized bipolar gain, increasing the device latch current. The avalanche energy which the device can successfully absorb while turning off an inductive load is significantly increased. The very deep increased conduction region is formed before the body and source regions in a novel process for making the new junction pattern.
    Type: Grant
    Filed: February 27, 1997
    Date of Patent: May 18, 1999
    Assignee: International Rectifier Corp.
    Inventors: Perry Merrill, Herbert J. Gould
  • Patent number: 5899711
    Abstract: A method for enhancing hydrogenation of an oxide-coated polycrystalline silicon thin-film transistor or devices includes depositing a metal capping layer on the device prior to hydrogenation. In addition, a method for batch hydrogenation of substrates or plates carrying the oxide-coated polycrystalline silicon devices includes placing the plates in a downstream flow from a hydrogen plasma.
    Type: Grant
    Filed: October 11, 1996
    Date of Patent: May 4, 1999
    Assignee: Xerox Corporation
    Inventor: Donald L. Smith
  • Patent number: 5897346
    Abstract: In producing a semiconductor device such as a thin film transistor (TFT), a silicon semiconductor film is formed on a substrate having an insulating surface, such as a glass substrate, and then a silicon nitride film is formed on the silicon semiconductor film. After that, a hydrogen ion, fluorine ion, or chlorine ion is introduced into the silicon semiconductor film through the silicon nitride film, and then the silicon semiconductor film into which an ion is introduced is heated in an atmosphere containing hydrogen, fluorine, chlorine or these mixture, to neutralize dangling bonds in the silicon semiconductor film and reduce levels in the silicon semiconductor film.
    Type: Grant
    Filed: November 27, 1996
    Date of Patent: April 27, 1999
    Assignee: Semiconductor Energy Laboratory Co., Ltd.
    Inventors: Naoaki Yamaguchi, Hongyong Zhang, Satoshi Teramoto, Hideto Ohnuma
  • Patent number: 5891764
    Abstract: A laser processing process which comprises laser annealing a silicon film 2 .mu.m or less in thickness by irradiating a laser beam 400 nm or less in wavelength and being operated in pulsed mode with a pulse width of 50 nsec or more, and preferably, 100 nsec or more.A laser processing apparatus which comprises a laser generation device and a stage for mounting thereon a sample provided separately from said device, to thereby prevent transfer of vibration attributed to the movement of the stage to the laser generation device and the optical system. A stable laser beam can be obtained to thereby improve productivity.
    Type: Grant
    Filed: October 30, 1996
    Date of Patent: April 6, 1999
    Assignee: Semiconductor Energy Laboratory Co., Ltd.
    Inventors: Hiroaki Ishihara, Kazuhisa Nakashita, Hideto Ohnuma, Nobuhiro Tanaka, Hiroki Adachi
  • Patent number: 5888857
    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.
    Type: Grant
    Filed: June 10, 1996
    Date of Patent: March 30, 1999
    Assignee: Semiconductor Energy Laboratory Co., Ltd.
    Inventors: Hongyong Zhang, Hideki Uochi, Toru Takayama, Takeshi Fukunaga, Yasuhiko Takemura
  • Patent number: 5888858
    Abstract: Concentration of metal element which promotes crystallization of silicon and which exists within a crystal silicon film obtained by utilizing the metal element is reduced. A first heat treatment for crystallization is implemented after introducing nickel to an amorphous silicon film. Then, after obtaining the crystal silicon film, another heat treatment is implemented within an oxidizing atmosphere at a temperature higher than that of the previous heat treatment. A thermal oxide film is formed in this step. At this time, gettering of the nickel element into the thermal oxide film takes place. Then, the thermal oxide film is removed. Thereby, a crystal silicon film having low concentration of the metal element and a high crystalinity can be obtained.
    Type: Grant
    Filed: January 16, 1997
    Date of Patent: March 30, 1999
    Assignee: Semiconductor Energy Laboratory Co., Ltd.
    Inventors: Shunpei Yamazaki, Satoshi Teramoto, Jun Koyama, Yasushi Ogata, Masahiko Hayakawa, Mitsuaki Osame
  • Patent number: 5888856
    Abstract: In a top-gate type thin film transistor including a polycrystalline silicon pattern having a channel region, a source region and a drain region on a substrate, a gate electrode via a gate insulating layer on the polycrystalline silicon layer, an insulating layer thereon, and metal electrodes coupled to the source region and the drain region, dangling bonds of silicon of the channel region at an interface with the gate insulating layer and dangling bonds of silicon of a part of the drain region are combined with hydrogen.
    Type: Grant
    Filed: April 19, 1996
    Date of Patent: March 30, 1999
    Assignee: NEC Corporation
    Inventor: Koji Hamada
  • Patent number: 5883016
    Abstract: A method for hydrogenating a thin film semiconductor wafer and an apparatus for performing the method. The method comprises the steps of applying a pulsed potential having a predetermined amplitude, a predetermined frequency, and a predetermined pulse duration to the thin film semiconductor wafer while exposing the thin film semiconductor wafer to a hydrogen plasma. The apparatus performs this method through the utilization of an inductively-coupled plasma (ICP) source so as to allow saturation of device parameter improvements within a reduced process time of 5 minutes. The ICP source allows this reduced process time to be achieved in a low energy, high dose rate plasma immersion ion implantation (PIII) hydrogenation process according to the present invention.
    Type: Grant
    Filed: April 4, 1996
    Date of Patent: March 16, 1999
    Assignee: Northeastern University
    Inventors: Chung Chan, Shu Qin
  • Patent number: 5879975
    Abstract: The etch profile of side surfaces of a gate electrode is improved by heat treating the gate electrode layer after nitrogen implantation and before etching to form the gate electrode. Nitrogen implantation at high dosages to prevent subsequent impurity penetration through the gate dielectric layer, e.g., B penetration, amorphizes the upper portion of the gate electrode layer resulting in concave side surfaces upon etching to form the gate electrode. Heat treatment performed after nitrogen implantation can restore sufficient crystallinity so that, after etching the gate electrode layer, the side surfaces of the resulting gate electrode are substantially parallel.
    Type: Grant
    Filed: September 5, 1997
    Date of Patent: March 9, 1999
    Assignee: Advanced Micro Devices, Inc.
    Inventors: Olov Karlsson, Effiong Ibok, Dong-Hyuk Ju, Scott A. Bell, Daniel A. Steckert, Robert Ogle
  • Patent number: 5879974
    Abstract: 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: Grant
    Filed: August 1, 1996
    Date of Patent: March 9, 1999
    Assignee: Semiconductor Energy Laboratory Co., Ltd.
    Inventor: Shunpei Yamazaki
  • Patent number: 5834345
    Abstract: A method of fabricating a field effect thin film transistor is provided, in which, after a first amorphous semiconductor layer having a predetermined thickness is deposited on a gate insulating film, the first amorphous semiconductor layer is transformed to a micro-crystal semiconductor layer by exposing it to hydrogen plasma produced by hydrogen discharge and, then, a second amorphous semiconductor layer is deposited on the micro-crystal semiconductor layer. According to this method, it is possible to fabricate a high performance and high quality field effect thin film transistor through a simplified step of forming the micro-crystal semiconductor which becomes a channel region thereof.
    Type: Grant
    Filed: September 24, 1996
    Date of Patent: November 10, 1998
    Assignee: NEC Corporation
    Inventor: Kousaku Shimizu
  • Patent number: 5830784
    Abstract: A silicon film provided on a blocking film 102 on a substrate 101 is made amorphous by doping Si+, and in a heat-annealing process, crystallization is started in parallel to a substrate from an area 100 where lead serving as a crystallization-promoting catalyst is introduced.
    Type: Grant
    Filed: September 19, 1996
    Date of Patent: November 3, 1998
    Assignee: Semiconductor Energy Laboratory Company, Ltd.
    Inventors: Hongyong Zhang, Toru Takayama
  • Patent number: 5824573
    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.
    Type: Grant
    Filed: June 5, 1995
    Date of Patent: October 20, 1998
    Assignee: Semiconductor Energy Laboratory Co., Ltd.
    Inventors: Hongyong Zhang, Toru Takayama, Yasuhiko Takemura
  • Patent number: 5808318
    Abstract: A polycrystalline semiconductor thin film formed in a stripe shape on an insulating substrate wherein crystal particles are arranged in a line-texture form in a longitudinal direction of a stripe; an electric field effect mobility .nu..sub.L in a longitudinal direction of a stripe is different from an electric field effect mobility .nu..sub.S in a width direction of the stripe, and .nu..sub.L .gtoreq.1.5.multidot..nu..sub.S is satisfied.
    Type: Grant
    Filed: March 28, 1997
    Date of Patent: September 15, 1998
    Assignee: AG Technology Co., Ltd.
    Inventors: Kunio Masumo, Masaya Kunigita
  • Patent number: 5792679
    Abstract: A method for fabricating a GeSi/Si/SiO.sub.2 heterostructure comprises the steps of: (a) providing a monocrystalline Si substrate; (b) defining a GeSi region within the Si substrate while leaving a Si cap overlying the GeSi region, the Si cap being an integral part of the monocrystalline substrate; and (c) oxidizing part of the Si cap to thereby produce the GeSi/Si/SiO.sub.2 heterostructure.
    Type: Grant
    Filed: August 30, 1993
    Date of Patent: August 11, 1998
    Assignees: Sharp Microelectronics Technology, Inc., Sharp Kabushiki Kaisha
    Inventor: Tatsuo Nakato
  • Patent number: 5780347
    Abstract: A method and apparatus of forming local interconnects in a MOS process deposits a layer of polysilicon over an entire region after several conventional MOS processing steps. The region is then masked to provide protected regions and unprotected regions. The mask may be used to define local interconnects and other conductive elements such as the source and drain contact regions for a MOS transistor. After masking, the region is bombarded with atoms to enhance the oxidation potential of the unprotected regions. The masking is removed and the substrate is then exposed to oxidizing conditions which cause the unprotected regions to rapidly oxidize to form a thick oxide layer. The formerly protected polysilicon regions may then be doped to render them conductive.
    Type: Grant
    Filed: May 20, 1996
    Date of Patent: July 14, 1998
    Inventor: Ashok K. Kapoor
  • Patent number: 5776804
    Abstract: A thin film transistor formed on a non-single crystal silicon layer is exposed to hydrogen ion radiated from hydrogen plasma at 300 degrees to 400 degrees centigrade so as to deactivate trapping levels in the non-single crystal silicon layer, and, thereafter, the thin film transistor is annealed in nitrogen atmosphere at 200 degrees to 300 degrees centigrade so as to evacuate residual hydrogen from, for example, a gate insulating layer, thereby improving the transistor characteristics of the thin film transistor.
    Type: Grant
    Filed: October 25, 1996
    Date of Patent: July 7, 1998
    Assignee: NEC Corporation
    Inventor: Fumihiko Hayashi
  • Patent number: 5773328
    Abstract: A field-effect transistor structure wherein a single patterned thin film semiconductor layer: is monocrystalline, and epitaxially matched to and dielectrically isolated from an underlying body region, in channel locations; and is polycrystalline in source/drain locations which abut said channel locations.
    Type: Grant
    Filed: June 7, 1995
    Date of Patent: June 30, 1998
    Assignee: SGS-Thomson Microelectronics, Inc.
    Inventor: Richard A. Blanchard
  • Patent number: 5773329
    Abstract: 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: Grant
    Filed: July 24, 1996
    Date of Patent: June 30, 1998
    Assignee: International Business Machines Corporation
    Inventor: Yue Kuo
  • Patent number: 5770485
    Abstract: An amorphized implant is performed to retard diffusion of ions in the source and drain regions. By retarding the diffusion of ions in these regions, a shallower junction is advantageously created in the silicon regions of the wafer. A slight degradation in leakage current is obtained if the amorphized implant is performed on both the source and the drain sides of a transistor. However, since the source region is a low voltage region with a very shallow junction, MOSFETs in both n-channel and p-channel regions are formed with improved performance and reliability. A method of fabricating an integrated circuit includes forming a gate electrode over a semiconductor substrate, forming a source mask extending over the drain region of the semiconductor substrate, and implanting an implant species into the source region of the semiconductor substrate to form an amorphous implant layer of the semiconductor substrate.
    Type: Grant
    Filed: March 4, 1997
    Date of Patent: June 23, 1998
    Assignee: Advanced Micro Devices, Inc.
    Inventors: Mark I. Gardner, H. Jim Fulford, Jr., Derick J. Wristers
  • Patent number: 5753560
    Abstract: A semiconductor structure (20) includes a silicon layer (16) formed on an oxide layer (14). Gettering sinks (31, 32) are formed in the silicon layer (16). Lateral gettering is performed to effectively remove impurities from a first section (26) of the semiconductor layer (16). An insulated gate semiconductor device (40) is then formed in semiconductor layer (16), wherein a channel region (55) of the device (40) is formed in the first section (26) of the semiconductor layer (16). A gate dielectric layer (42) of the device (40) is formed over a portion of the first section (26) after the lateral gettering process, thereby enhancing the integrity of the gate dielectric layer (42).
    Type: Grant
    Filed: October 31, 1996
    Date of Patent: May 19, 1998
    Assignee: Motorola, Inc.
    Inventors: Stella Q. Hong, Thomas A. Wetteroth, Syd Robert Wilson