With Schottky Gate Patents (Class 257/280)
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Publication number: 20110114999Abstract: To provide a deposition technique for forming an oxide semiconductor film. An oxide semiconductor film is formed using a sputtering target which contains a sintered body of metal oxide and in which the concentration of hydrogen contained in the sintered body of metal oxide is, for example, as low as 1×1016 atoms/cm3 or lower, so that the oxide semiconductor film contains a small amount of impurities such as a hydrogen atom and a compound containing a hydrogen atom typified by H2O. Further, this oxide semiconductor film is used as an active layer of a transistor.Type: ApplicationFiled: November 12, 2010Publication date: May 19, 2011Applicant: SEMICONDUCTOR ENERGY LABORATORY CO., LTD.Inventors: Shunpei Yamazaki, Toru TAKAYAMA, Keiji SATO
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Patent number: 7943972Abstract: A unit cell of a metal-semiconductor field-effect transistor (MESFET) is provided. The MESFET has a source, a drain and a gate. The gate is between the source and the drain and on an n-type conductivity channel layer. A p-type conductivity region is provided beneath the gate between the source and the drain. The p-type conductivity region is spaced apart from the n-type conductivity channel layer and electrically coupled to the gate. Related methods are also provided herein.Type: GrantFiled: November 30, 2009Date of Patent: May 17, 2011Assignee: Cree, Inc.Inventors: Saptharishi Sriram, Matt Willis
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Patent number: 7939865Abstract: In one embodiment, a metal-semiconductor field effect transistor (MESFET) comprises a first silicon layer, an insulator layer formed on the first silicon layer, and a second silicon layer formed on the insulator layer. A gate region, a source region, and a drain region are formed in the second silicon layer. A first partial trench is formed in the second silicon layer between at least a portion of the gate region and at least a portion of the source region, wherein the first partial trench stops short of the insulator layer. A second partial trench formed in the second silicon layer between at least a portion of the gate region and at least a portion of the drain region, wherein the second partial trench stops short of the insulator layer. First and second oxide spacers are formed in the first and second partial trenches. The first and second oxide spacers and the source region, gate region, and the drain region are substantially planar.Type: GrantFiled: January 22, 2009Date of Patent: May 10, 2011Assignee: Honeywell International Inc.Inventor: Paul Fechner
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Patent number: 7928480Abstract: A semiconductor device has a semiconductor layer, and a first electrode (Schottky electrode or MIS electrode) and a second electrode (ohmic electrode) which are formed on the semiconductor layer apart from each other. The first electrode has a cross section in the shape of a polygon. A second electrode-side corner of the polygon has an interior angle of which an outward extension line of a bisector crosses the semiconductor layer or the second electrode. The interior angle of such a second electrode-side corner is larger than 90°.Type: GrantFiled: November 30, 2006Date of Patent: April 19, 2011Assignee: Sharp Kabushiki KaishaInventors: Masaharu Yamashita, John Kevin Twynam
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Patent number: 7893467Abstract: A silicon carbide semiconductor device includes a substrate; a drift layer having a first conductivity type; an insulating layer; a Schottky electrode; an ohmic electrode; a resurf layer; and second conductivity type layers. The drift layer and the second conductivity type layers provide multiple PN diodes. Each second conductivity type layer has a radial width with respect to a center of a contact region between the Schottky electrode and the drift layer. A radial width of one of the second conductivity type layers is smaller than that of another one of the second conductivity type layers, which is disposed closer to the center of the contact region than the one of the second conductivity type layers.Type: GrantFiled: May 27, 2008Date of Patent: February 22, 2011Assignee: DENSO CORPORATIONInventors: Takeo Yamamoto, Eiichi Okuno
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Publication number: 20110012680Abstract: A semiconductor device and a radio frequency circuit which are appropriate for multiband, multimode performance can be realized as a semiconductor device including a field-effect transistor formed on a semiconductor substrate, and include: ohmic electrodes serving as source and drain electrodes of the field-effect transistor, first and second Schottky electrodes provided between the ohmic electrodes and serving as gate electrodes of the field-effect transistor, and a third Schottky electrode provided and grounded between the first and second Schottky electrodes.Type: ApplicationFiled: July 9, 2010Publication date: January 20, 2011Applicant: PANASONIC CORPORATIONInventors: Junji KAIDO, Masahiko INAMORI, Shinichi SONETAKA, Hiroaki KAWANO
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Patent number: 7872285Abstract: Affords epitaxial substrates for vertical gallium nitride semiconductor devices that have a structure in which a gallium nitride film of n-type having a desired low carrier concentration can be provided on a gallium nitride substrate of n type. A gallium nitride epitaxial film (65) is provided on a gallium nitride substrate (63). A layer region (67) is provided in the gallium nitride substrate (63) and the gallium nitride epitaxial film (65). An interface between the gallium nitride substrate (43) and the gallium nitride epitaxial film (65) is positioned in the layer region (67). In the layer region (67), a peak value of donor impurity along an axis from the gallium nitride substrate (63) to the gallium nitride epitaxial film (65) is 1×1018 cm?3 or more. The donor impurity is at least either silicon or germanium.Type: GrantFiled: March 1, 2006Date of Patent: January 18, 2011Assignee: Sumitomo Electric Industries, Ltd.Inventors: Shin Hashimoto, Makoto Kiyama, Tatsuya Tanabe, Kouhei Miura, Takashi Sakurada
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Patent number: 7868356Abstract: A III-V field effect transistor comprising a semiconductor channel layer having an electrically conducting channel; an ohmic contact layer on the semiconductor channel layer, the ohmic contact layer having a recess structure disposed therethrough to the semiconductor channel layer; the bottom of the ohmic contact layer comprising an etch stop layer comprising Aluminium and Phosphorous and defining the shape of the recess at its junction with the semiconductor channel layer.Type: GrantFiled: April 30, 2009Date of Patent: January 11, 2011Assignee: Filtronic PLCInventors: Matthew Francis O'Keefe, Michael Charles Clausen, Richard Alun Davies, Robert Grey
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Patent number: 7859087Abstract: A semiconductor device includes: a semiconductor layer; at least one electrode formed on a semiconductor layer to be in contact with the semiconductor layer; and a passivation film covering the semiconductor layer and at least part of the top surface of the electrode to protect the semiconductor layer and formed of a plurality of sub-films. The passivation film includes a first sub-film made of aluminum nitride.Type: GrantFiled: December 14, 2009Date of Patent: December 28, 2010Assignee: Panasonic CorporationInventors: Tomohiro Murata, Hiroaki Ueno, Hidetoshi Ishida, Tetsuzo Ueda, Yasuhiro Uemoto, Tsuyoshi Tanaka, Daisuke Ueda
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Publication number: 20100320508Abstract: The present invention provides a horizontally depleted Metal Semiconductor Field Effect Transistor (MESPET). A drain region, a source region, and a channel region are formed in the device layer such that the drain region and the source region are spaced apart from one another and the channel region extends between the drain region and the source region. First and second gate contacts are formed in the device layer on either side of the channel region, and as such, the first and second gate contacts will also reside between opposing portions of the source and drain regions. With this configuration, voltages applied to the first and second gate contacts effectively control vertical depletion regions, which form on either side of the channel region.Type: ApplicationFiled: September 12, 2008Publication date: December 23, 2010Applicant: Arizona Board of Regents for and on behalf of Arizona State UniversityInventors: Joseph E. Ervin, Trevor John Thornton
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Patent number: 7851831Abstract: A transistor includes a nitride semiconductor layer and a gate electrode layer. The gate electrode layer includes a tantalum nitride layer on the nitride semiconductor layer. The tantalum nitride layer forms a Schottky junction with the nitride semiconductor layer. The transistor also includes an insulating film on the nitride semiconductor layer. The insulating film surrounds the gate electrode layer. A first portion of the gate electrode layer, in contact with the nitride semiconductor layer, has a higher nitrogen mole fraction than a second portion of the gate electrode layer.Type: GrantFiled: September 24, 2007Date of Patent: December 14, 2010Assignee: Mitsubishi Electric CorporationInventors: Hidetoshi Koyama, Yoshitaka Kamo, Toshihiko Shiga
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Patent number: 7851830Abstract: A multigate Schottky diode comprising an electrically conducting active semiconductor region; first and second electrically connected metallic contact arms on the active semiconductor region forming ohmic contacts therewith; the ohmic contacts being spaced apart on the active semiconductor region to define a gate receiving channel therebetween. a plurality of electrically connected metallic gate fingers, the metallic gate fingers being in contact with the active semiconductor region to form Schottky junctions, the Schottky junctions being spaced apart on the active semiconductor region and extending at least partially along the gate receiving channel.Type: GrantFiled: November 21, 2007Date of Patent: December 14, 2010Assignee: RFMD (UK) LimitedInventors: Ronald Arnold, Dennis Michael Brookbanks
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Publication number: 20100301400Abstract: Improved Schottky diodes (20, 20?) with reduced leakage current and improved breakdown voltage are provided by building a JFET with its current path (50, 50?) of a first conductivity type serially located between a first terminal (80, 80?, 32, 32?) comprising a Schottky contact (33, 33?) and a second (82, 82?, 212, 212?) terminal. The current path (50, 50?) lies (i) between multiple substantially parallel finger regions (36, 36?) of a second, opposite, conductivity type substantially laterally outboard of the Schottky contact (33, 33?), and (ii) partly above a buried region (44, 44?) of the second conductivity type that underlies a portion (46, 46?) of the current path (50, 50?), which regions (36, 36?; 44, 44?) are electrically coupled to the first terminal (80, 80?, 32, 32?) and the Schottky contact (33, 33?) and which portion (46, 46?) is electrically coupled to the second terminal (82, 82?, 212, 212?).Type: ApplicationFiled: May 28, 2009Publication date: December 2, 2010Applicant: Freescale Semiconductor, Inc.Inventors: Xin Lin, Daniel J. Blomberg, Jiang-Kai Zuo
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Patent number: 7838914Abstract: The present invention miniaturizes a HEMT element used as a switching element in a radio frequency module. A single gate electrode 17 is formed in an active region defined by an element separation portion 9 on a main surface of a substrate 1 comprising GaAs. The gate electrode 17 is patterned so as to extend in the vertical direction of the page surface between source electrodes 13 and drain electrodes 14, and to extend in left and right directions at other portions. Thus, the ratio of the gate electrode 17 disposed outside the active region is reduced, and the area of a gate pad 17A is reduced.Type: GrantFiled: November 6, 2007Date of Patent: November 23, 2010Assignee: Renesas Electronics CorporationInventors: Masao Yamane, Atsushi Kurokawa, Shinya Osakabe, Eigo Tange, Yasushi Shigeno, Hiroyuki Takazawa
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Publication number: 20100264467Abstract: A transistor component having a shielding structure. One embodiment provides a source terminal, a drain terminal and control terminal. A source zone of a first conductivity type is connected to the source terminal. A drain zone of the first conductivity type is connected to the drain terminal. A drift zone is arranged between the source zone and the drain zone. A junction control structure is provided for controlling a junction zone in the drift zone between the drain zone and the source zone, at least including one control zone. A shielding structure is arranged in the drift zone between the junction control structure and the drain zone and at least includes a shielding zone of a second conductivity type being complementarily to the first conductivity type. The shielding zone is connected to a terminal for a shielding potential.Type: ApplicationFiled: April 17, 2009Publication date: October 21, 2010Applicant: INFINEON TECHNOLOGIES AUSTRIA AGInventors: Dethard Peters, Peter Friedrichs, Rudolf Elpelt, Larissa Wehrhahn-Kilian, Michael Treu, Roland Rupp
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Publication number: 20100259321Abstract: Embodiments include but are not limited to apparatuses and systems including a field-effect transistor switch. A field-effect transistor switch may include a first field plate coupled with a gate electrode, the first field plate disposed substantially equidistant from a source electrode and a drain electrode. The field-effect transistor switch may also include a second field plate proximately disposed to the first field plate and disposed substantially equidistant from the source electrode and the drain electrode. The first and second field plates may be configured to reduce an electric field between the source electrode and the gate electrode and between the drain electrode and the gate electrode.Type: ApplicationFiled: April 14, 2009Publication date: October 14, 2010Applicant: TRIQUINT SEMICONDUCTOR, INC.Inventors: Hua-Quen Tserng, Deep C. Dumka, Martin E. Jones, Charles F. Campbell, Anthony M. Balistreri
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Publication number: 20100244105Abstract: A semiconductor structure having: a semiconductor comprising a indium gallium phosphide and molybdenum metal in Schottky contact with the semiconductor.Type: ApplicationFiled: March 31, 2009Publication date: September 30, 2010Inventor: Kiuchul Hwang
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Publication number: 20100187577Abstract: Improved Schottky diodes (20) with reduced leakage current and improved breakdown voltage are provided by building a JFET (56) into the diode, serially located in the anode-cathode current path (32). The gates of the JFET (56) formed by doped regions (38, 40) placed above and below the diode's current path (32) are coupled to the anode (312) of the diode (20), and the current path (32) passes through the channel region (46) of the JFET (56). Operation is automatic so that as the reverse voltage increases, the JFET (56) channel region (46) pinches off, thereby limiting the leakage current and clamping the voltage across the Schottky junction (50) at a level below the Schottky junction (50) breakdown. Increased reverse voltage can be safely applied until the device eventually breaks down elsewhere. The impact on device area and area efficiency is minimal and the device can be built using a standard fabrication process so that it can be easily integrated into complex ICs.Type: ApplicationFiled: January 26, 2009Publication date: July 29, 2010Applicant: FREESCALE SEMICONDUCTOR, INC.Inventors: Xin Lin, Daniel J. Blomberg, Jiang-Kai Zuo
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Publication number: 20100148718Abstract: A semiconductor element (20) of the present invention includes a plurality of field effect transistors (90) and a schottky electrode (9a), and the schottky electrode (9a) is formed along an outer periphery of a region where the plurality of field effect transistors (90) are formed.Type: ApplicationFiled: July 21, 2006Publication date: June 17, 2010Applicant: MATSUSHITA ELECTRIC INDUSTRIAL CO., LTD.Inventors: Makoto Kitabatake, Osamu Kusumoto, Masao Uchida, Kenya Yamashita
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Patent number: 7737476Abstract: Metal-semiconductor field-effect transistors (MESFETS) are provided. A MESFET is provided having a source region, a drain region and a gate. The gate is between the source region and the drain region. A p-type conductivity layer is provided beneath the source region, the p-type conductivity layer being self-aligned to the gate. Related methods of fabricating MESFETs are also provided herein.Type: GrantFiled: February 15, 2007Date of Patent: June 15, 2010Assignee: Cree, Inc.Inventors: Saptharishi Sriram, Jason Henning, Keith Wieber
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Publication number: 20100140672Abstract: A field effect transistor includes a Schottky layer; a stopper layer formed of InGaP and provided in a recess region on the Schottky layer; a cap layer provided on the stopper layer and formed of GaAs; and a barrier rising suppression region configured to suppress rising of a potential barrier due to interface charge between the stopper layer and the cap layer. The cap layer includes a high concentration cap layer, and a low concentration cap layer provided directly or indirectly under the high concentration cap layer and having an impurity concentration lower than the high concentration cap layer.Type: ApplicationFiled: December 7, 2009Publication date: June 10, 2010Applicant: NEC Electronics CorporationInventors: Masayuki AOIKE, Yasunori Bito
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Patent number: 7732868Abstract: A protecting element, comprising a first n+-type region, an insulating region, and a second n+-type region, is connected in parallel between two terminals of an FET. Since discharge across the first and second n+ regions is enabled, electrostatic energy that reaches the operating region of the FET can be attenuated without increasing the parasitic capacitance.Type: GrantFiled: November 28, 2002Date of Patent: June 8, 2010Assignee: Sanyo Electric Co., Ltd.Inventors: Tetsuro Asano, Mikito Sakakibara, Toshikazu Hirai
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Patent number: 7723761Abstract: In one embodiment, a tiered gate structure is provided having a substrate including a source, a drain and a gate thereon. The gate includes an elongated gate foot having a first deposition gate material extending from the substrate, the elongated gate foot having a top portion distal from the substrate. The gate head has a second deposition gate material and includes an elongated portion extending downward from the gate head to connect to the top portion of the elongated gate foot.Type: GrantFiled: September 17, 2008Date of Patent: May 25, 2010Assignee: HRL Laboratories, LLCInventors: Ivan Milosavljevic, Adele Schmitz, Michael Delaney, Michael Antcliffe
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Publication number: 20100123172Abstract: A substrate composed of hexagonally crystalline SiC is prepared such that its main surface is in the direction at which the minimum angle between the main surface and a plane perpendicular to the (0001) plane is one degree or less, for example, in the direction at which the minimum angle between the main surface and the [0001] direction, which is perpendicular to the (0001) plane, is one degree or less. A horizontal semiconductor device is formed on one main surface of the substrate prepared by the foregoing method. Thus, it was possible to improve the value of breakdown voltage significantly over the horizontal semiconductor device in which the main surface of the substrate composed of hexagonally crystalline SiC is in the direction along the (0001) direction.Type: ApplicationFiled: October 3, 2008Publication date: May 20, 2010Applicant: SUMITOMO ELECTRIC INDUSTRIES, LTD.Inventors: Kazuhiro Fujikawa, Shin Harada
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Patent number: 7719055Abstract: A normally-off cascode power switch circuit is disclosed fabricated in wide bandgap semiconductor material such as silicon carbide or gallium nitride and which is capable of conducting current in the forward and reverse direction under the influence of a positive gate bias. The switch includes cascoded junction field effect transistors (JFETs) that enable increased gain, and hence blocking voltage, while minimizing specific on-resistance.Type: GrantFiled: May 10, 2007Date of Patent: May 18, 2010Assignee: Northrop Grumman Systems CorporationInventors: Ty R. McNutt, John V. Reichl, Harold C. Heame, III, Eric J. Stewart, Stephen D. Van Campen, Victor D. Veliadis
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Patent number: 7714365Abstract: A description is given of a semiconductor component comprising a drift zone of a first conduction type and at least one Schottky metal zone arranged in the drift zone, and of a method for producing a semiconductor component.Type: GrantFiled: February 21, 2008Date of Patent: May 11, 2010Assignee: Infineon Technologies Austria AGInventor: Wolfgang Werner
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Patent number: 7700975Abstract: Metal-Semiconductor-Metal (“MSM”) photodetectors and methods to fabricate thereof are described. The MSM photodetector includes a thin heavily doped (“delta doped”) layer deposited at an interface between metal contacts and a semiconductor layer to reduce a dark current of the MSM photodetector. In one embodiment, the semiconductor layer is an intrinsic semiconductor layer. In one embodiment, the thickness of the delta doped layer is less than 100 nanometers. In one embodiment, the delta doped layer has a dopant concentration of at least 1×1018 cm?3. A delta doped layer is formed on portions of a semiconductor layer over a substrate. Metal contacts are formed on the delta doped layer. A buffer layer may be formed between the substrate and the semiconductor layer. In one embodiment, the substrate includes silicon, and the semiconductor layer includes germanium.Type: GrantFiled: March 31, 2006Date of Patent: April 20, 2010Assignee: Intel CorporationInventors: Titash Rakshit, Miriam Reshotko
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Patent number: 7701032Abstract: A separation element formed of one of a conduction region and a metal layer is placed between two elements in proximity to each other. The separation element is connected to a high resistance element and to a direct current terminal pad. A connection route extending from the direct current terminal pad to the separation element is a route in which a potential does not vibrate with high frequency. This results in a placement of a high frequency GND potential between the two elements, at least one of which is subjected to transmitting the high frequency signals, whereby leak of the high frequency signals can be prevented between the two elements.Type: GrantFiled: May 30, 2006Date of Patent: April 20, 2010Assignee: SANYO Electric Co., Ltd.Inventors: Tetsuro Asano, Yuichi Kusaka, Mikito Sakakibara
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Patent number: 7692222Abstract: A semiconductor structure and method wherein a recess is disposed in a surface portion of a semiconductor structure and a dielectric film is disposed on and in contract with the semiconductor. The dielectric film has an aperture therein. Portions of the dielectric film are disposed adjacent to the aperture and overhang underlying portions of the recess. An electric contact has first portions thereof disposed on said adjacent portions of the dielectric film, second portions disposed on said underlying portions of the recess, with portions of the dielectric film being disposed between said first portion of the electric contact and the second portions of the electric contact, and third portions of the electric contact being disposed on and in contact with a bottom portion of the recess in the semiconductor structure. The electric contact is formed by atomic layer deposition of an electrically conductive material over the dielectric film and through the aperture in such dielectric film.Type: GrantFiled: November 7, 2006Date of Patent: April 6, 2010Assignee: Raytheon CompanyInventors: Kamal Tabatabaie, Robert B. Hallock
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Publication number: 20100059798Abstract: There is provided a semiconductor device including: a SiC substrate; an AlGaN layer formed on the SiC substrate; a source electrode and a drain electrode formed on the AlGaN layer so as to be spaced from each other; a first insulation film formed between the source electrode and the drain electrode and having a band-like opening parallel to the drain electrode and the source electrode; a gate electrode formed at the opening in the first insulation film; a second insulation film formed on the first insulation film in such a manner as to cover a surface of the gate electrode; and a source field plate electrode which is formed on the second insulation film and the source electrode and an end portion of which on the drain electrode side is spaced from the second insulation film, thereby suppressing degradation in device performance.Type: ApplicationFiled: September 4, 2009Publication date: March 11, 2010Applicant: KABUSHIKI KAISHA TOSHIBAInventor: Hisao KAWASAKI
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Publication number: 20100032731Abstract: In accordance with an aspect of the invention, A Schottky junction field effect transistor (JFET) is created using cobalt silicide, or other Schottky material, to form the gate contact of the JFET. The structural concepts can also be applied to a standard JFET that uses N? type or P? type dopants to form the gate of the JFET. In addition, the structures allow for an improved JFET linkup with buried linkup contacts allowing improved noise and reliability performance for both conventional diffusion (N? and P? channel) JFET structures and for Schottky JFET structures. In accordance with another aspect of the invention, the gate poly, as found in a standard CMOS or BiCMOS process flow, is used to perform the linkup between the source and the junction gate and/or between the drain and the junction gate of a junction filed effect transistor (JFET).Type: ApplicationFiled: July 6, 2009Publication date: February 11, 2010Inventors: Jeffrey A. Babcock, Natalia Lavrovskaya, Saurabh Desai, Alexei Sadovnikov
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Publication number: 20100032730Abstract: A method of making a semiconductor device includes forming a p-type semiconductor region to an n-type semiconductor substrate in such a manner that the p-type semiconductor region is partially exposed to a top surface of the semiconductor substrate, forming a Schottky electrode of a first material in such a manner that the Schottky electrode is in Schottky contact with an n-type semiconductor region exposed to the top surface of the semiconductor substrate, and forming an ohmic electrode of a second material different from the first material in such a manner that the ohmic electrode is in ohmic contact with the exposed p-type semiconductor region. The Schottky electrode is formed earlier than the ohmic electrode.Type: ApplicationFiled: August 4, 2009Publication date: February 11, 2010Applicant: DENSO CORPORATIONInventors: Takeshi Endo, Eiichi Okuno, Takeo Yamamoto, Hirokazu Fujiwara, Masaki Konishi, Yukihiko Watanabe, Takashi Katsuno
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Publication number: 20100019249Abstract: Devices and methods for providing JFET transistors with improved operating characteristics are provided. Specifically, one or more embodiments of the present invention relate to JFET transistors with a higher diode turn-on voltage. For example, one or more embodiments include a JFET with a doped silicon-carbide gate, while other embodiments include a JFET with a metal gate. One or more embodiments also relate to systems and devices in which the improved JFET may be employed, as well as methods of manufacturing the improved JFET.Type: ApplicationFiled: July 24, 2008Publication date: January 28, 2010Applicant: MICRON TECHNOLOGY, INC.Inventor: Chandra Mouli
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Patent number: 7649217Abstract: An active electronic device has drain and source electrodes that make ohmic conduct with a layer of a semiconductor. The semiconductor layer may be a thin layer of an organic or amorphous semiconductor. The drain and source electrodes are on a first face of the layer of semiconductor at locations that are spaced apart on either side of a channel. The device has a gate electrode on a second face of the layer of semiconductor adjacent to the channel. The gate electrode makes a Schottky contact with the semiconductor to produce a depletion region in the channel. The gate electrode may encapsulate the channel so that the channel is protected from contact with oxygen, water molecules or other materials in the environment. In some embodiments, the device has an additional gate electrode separated from the semiconductor layer by an insulating layer. Such embodiments combine features of OFETs and MESFETs.Type: GrantFiled: March 24, 2006Date of Patent: January 19, 2010Inventors: Arash Takshi, John Madden
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Patent number: 7646043Abstract: A unit cell of a metal-semiconductor field-effect transistor (MESFET) is provided. The MESFET has a source, a drain and a gate. The gate is between the source and the drain and on an n-type conductivity channel layer. A p-type conductivity region is provided beneath the gate between the source and the drain. The p-type conductivity region is spaced apart from the n-type conductivity channel layer and electrically coupled to the gate. Related methods are also provided herein.Type: GrantFiled: September 28, 2006Date of Patent: January 12, 2010Assignee: Cree, Inc.Inventors: Saptharishi Sriram, Matt Willis
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Publication number: 20090315083Abstract: A semiconductor structure which includes a trench gate FET is formed as follows. A plurality of trenches is formed in a semiconductor region using a mask. The mask includes (i) a first insulating layer over a surface of the semiconductor region, (ii) a first oxidation barrier layer over the first insulating layer, and (iii) a second insulating layer over the first oxidation barrier layer. A thick bottom dielectric (TBD) is formed along the bottom of each trench. The first oxidation barrier layer prevents formation of a dielectric layer along the surface of the semiconductor region during formation of the TBD.Type: ApplicationFiled: June 20, 2008Publication date: December 24, 2009Inventors: James Pan, Christopher Lawrence Rexer
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Patent number: 7633135Abstract: This invention discloses a bottom-anode Schottky (BAS) diode that includes an anode electrode disposed on a bottom surface of a semiconductor substrate. The bottom-anode Schottky diode further includes a sinker dopant region disposed at a depth in the semiconductor substrate extending substantially to the anode electrode disposed on the bottom surface of the semiconductor and the sinker dopant region covered by a buried Schottky barrier metal functioning as an Schottky anode.Type: GrantFiled: July 22, 2007Date of Patent: December 15, 2009Assignee: Alpha & Omega Semiconductor, Ltd.Inventor: François Hébert
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Patent number: 7612394Abstract: A thin film transistor array (TFT) substrate and a method for manufacturing the same are provided. The manufacturing method needs only or even less than six mask processes for manufacturing the TFT array substrate integrated with a color filter pattern. Therefore, the manufacturing method is simpler and the manufacturing cost is reduced. In addition, the manufacturing method needs not to form a contact window in a relative thick film layer such as a planarization layer or a color filter layer, so as to connect the pixel electrode to the source/drain, thus the difficulty of the manufacturing process is effectively reduced.Type: GrantFiled: November 10, 2006Date of Patent: November 3, 2009Assignee: Au Optronics CorporationInventors: Wei-Sheng Yu, Chien-Hung Chen
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Patent number: 7608907Abstract: An improved diode is disclosed. The diode comprises a Schottky diode and a LDMOS device coupled in series with the Schottky diode. In a preferred embodiment, a forward current from the Schottky diode is allowed to flow through the channel of a depletion mode LDMOS that allows gate control over Schottky forward current. Integrating the Schottky diode into the drain of the depletion mode LDMOS forms the device structure.Type: GrantFiled: January 6, 2005Date of Patent: October 27, 2009Assignee: Micrel, Inc.Inventor: Shekar Mallikarjunaswamy
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Publication number: 20090250730Abstract: An undoped AlGaN layer 13 is formed on a buffer layer composed of a GaN series material formed on a semiconductor substrate, a drain electrode 15 and a source electrode 16 forming ohmic junction with the undoped AlGaN layer 13 are formed separately from each other on the undoped AlGaN layer 13. A gate electrode 17 composed of metal Ni and Au laminated in this order is formed between the drain electrodes 15 and the source electrode 16 on the undoped AlGaN layer 13. The end portion 17-2 of the gate electrode 17 is formed on the underlying metal 18 formed by a metal containing Ti via an insulating film 14 on a GaN buffer layer 12 surrounding the undoped AlGaN layer 13.Type: ApplicationFiled: February 11, 2009Publication date: October 8, 2009Applicant: Kabushiki Kaisha ToshibaInventor: Hisao KAWASAKI
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Patent number: 7598548Abstract: A Schottky electrode including a WNx layer on an n-type GaN layer. A crystal plane of the n-type GaN layer is in contact with a crystal plane of the WNx layer. The crystal plane of the n-type GaN layer is a (0001)-plane, and the crystal plane of the WNx layer is (111)-oriented. The WNx layer may be an electrode layer having an NaCl-type structure including at least one metal selected from the group consisting of zirconium, hafnium, niobium, tantalum, molybdenum and tungsten, and at least one element selected from nitrogen and carbon. Further, the lattice constant of the electrode layer is preferably 0.95 to 1.05 times the a-axis lattice constant of the n-type GaN layer, multiplied by 2(1/2).Type: GrantFiled: December 1, 2005Date of Patent: October 6, 2009Assignee: Mitsubishi Denki Kabushiki KaishaInventor: Toshihiko Shiga
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Publication number: 20090242943Abstract: A semiconductor device which can prevent peeling off of a gate electrode is provided. The semiconductor device has GaN buffer layer formed on substrate 11, undoped AlGaN layer 13 formed on this buffer layer 12, drain electrode 16 and source electrode 17 formed separately on undoped AlGaN layer 13, which form ohmic junctions with undoped AlGaN layer 13. Between drain electrode 16 and source electrode 17, insulating layer 20 which has opening 19 is formed, and metal film is formed on a surface of insulating layer 2. Gate electrode 18 which forms a Schottky barrier junction with undoped AlGaN layer 13 is formed in opening 19, and gate electrode 18 adheres to metal film 21.Type: ApplicationFiled: February 10, 2009Publication date: October 1, 2009Applicant: Kabushiki Kaisha ToshibaInventor: Hisao KAWASAKI
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Publication number: 20090194796Abstract: Affords epitaxial substrates for vertical gallium nitride semiconductor devices that have a structure in which a gallium nitride film of n-type having a desired low carrier concentration can be provided on a gallium nitride substrate of n type. A gallium nitride epitaxial film (65) is provided on a gallium nitride substrate (63). A layer region (67) is provided in the gallium nitride substrate (63) and the gallium nitride epitaxial film (65). An interface between the gallium nitride substrate (43) and the gallium nitride epitaxial film (65) is positioned in the layer region (67). In the layer region (67), a peak value of donor impurity along an axis from the gallium nitride substrate (63) to the gallium nitride epitaxial film (65) is 1×1018 cm?3 or more. The donor impurity is at least either silicon or germanium.Type: ApplicationFiled: March 1, 2006Publication date: August 6, 2009Applicant: SUMITOMO ELECTRIC INDUSTRIES, LTD.Inventors: Shin Hashimoto, Makoto Kiyama, Tatsuya Tanabe, Kouhei Miura, Takashi Sakurada
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Publication number: 20090173973Abstract: A semiconductor device has a semiconductor (e.g., a silicon substrate), an electrically conductive region (e.g., a source region and a drain region) which is in contact with the semiconductor to form a Schottky junction, and an insulator. The insulator is in contact with the semiconductor and the electrically conductive region, and has a fixed-charge containing region which contains a fixed charge and extends across a boundary between the semiconductor and the electrically conductive region.Type: ApplicationFiled: November 26, 2008Publication date: July 9, 2009Inventor: Kenji KIMOTO
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Publication number: 20090154210Abstract: The present invention provides a bi-directional field effect transistor and a matrix converter using the same, in which a current flowing bi-directionally can be controlled by means of a single device. The bi-directional field effect transistor includes: a semiconductor substrate 1; a gate region which is arranged on the semiconductor substrate 1, with a channel parallel to a principal surface of the substrate 1 and a gate electrode 13a for controlling conductance of the channel; a first region which is arranged on a first side of the channel; and a second region which is arranged on a second side of the channel; wherein a forward current which flows from a first electrode 11a of the first region through the channel to a second electrode 12a of the second region and a backward current which flows from the second electrode 12a through the channel to the first electrode 11a can be controlled by a gate voltage applied to the gate electrode 13a.Type: ApplicationFiled: September 30, 2005Publication date: June 18, 2009Applicant: SUMITOMO ELECTRIC INDUSTRIES, LTD.Inventor: Kazuhiro Fujikawa
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Patent number: 7547932Abstract: A vertical gate-depleted single electron transistor (SET) is fabricated on a conducting or insulating substrate. A plurality of lightly doped basic materials and tunneling barriers are fabricated on top of a substrate, wherein at least two of the layers of basic materials sandwich the layers of tunneling barriers and at least two of the layers of tunneling barriers sandwich at least one of the layers of basic materials. A mesa is fabricated on top of the layers of basic materials and tunneling barriers, and has an undercut shape. An ohmic contact is fabricated on top of the mesa, and one or more gate Schottky contacts are fabricated on top of the layers of lightly doped basic materials and tunneling barriers. A quantum dot is induced by gate depletion, when a source voltage is set as zero, a drain voltage is set to be less than 0.1, and a gate voltage is set to be negative.Type: GrantFiled: November 22, 2002Date of Patent: June 16, 2009Assignee: The Regents of the University of CaliforniaInventors: Yaohui Zhang, Filipp A. Baron, Kang L. Wang
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Publication number: 20090146191Abstract: Method and apparatus are described for semiconductor devices. The method (100) comprises, providing a partially completed semiconductor device (31-1) including a substrate (21), a semiconductor (22) on the substrate (21) and a passivation layer (25) on the semiconductor (22), and using a first mask (32), locally etching the passivation layer (25) to expose a portion (36) of the semiconductor (22), and without removing the first mask (32) forming a Schottky contact (42-1) of a first material on the exposed portion (36) of the semiconductor (22), then removing the first mask (32) and using a further mask (44), forming a step-gate conductor (48-1) of a second material electrically coupled to the Schottky contact (42-1) and overlying parts (25-1) of the passivation layer (25) adjacent to the Schottky contact (42-1).Type: ApplicationFiled: December 5, 2007Publication date: June 11, 2009Applicant: FREESCALE SEMICONDUCTOR, INC.Inventors: Bruce M. Green, Haldane S. Henry, Chun-Li Liu, Karen E. Moore, Matthias Passlack
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Publication number: 20090134435Abstract: This invention proposes the use of a thermodynamic screen placed under the electronic devices whose excess noise is to be reduced in order to block the transverse currents between said devices and subjacent layers that are responsible for the aforementioned excess noise. For epitaxial layers as those used in Microelectronics, the barrier layer (2) with an opposed doping to the epilayer supporting the devices (4), and the non-doped separating layer (3) form the thermodynamic screen which, embedded between the epilayer (4) and the substrate (1), reduces the aforementioned transverse currents and thus the excess noise of the devices on the epilayer (4) when they are biased.Type: ApplicationFiled: November 10, 2006Publication date: May 28, 2009Applicant: UNIVERSIDAD POLITECNICA DE MADRIDInventor: Jose Ignacio Izpura
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Patent number: 7510921Abstract: A self-aligned silicon carbide power MESFET with improved current stability and a method of making the device are described. The device, which includes raised source and drain regions separated by a gate recess, has improved current stability as a result of reduced surface trapping effects even at low gate biases. The device can be made using a self-aligned process in which a substrate comprising an n+-doped SiC layer on an n-doped SiC channel layer is etched to define raised source and drain regions (e.g., raised fingers) using a metal etch mask. The metal etch mask is then annealed to form source and drain ohmic contacts. A single- or multilayer dielectric film is then grown or deposited and anisotropically etched. A Schottky contact layer and a final metal layer are subsequently deposited using evaporation or another anisotropic deposition technique followed by an optional isotropic etch of dielectric layer or layers.Type: GrantFiled: January 30, 2007Date of Patent: March 31, 2009Assignee: SemiSouth Laboratories, Inc.Inventors: Igor Sankin, Janna B. Casady, Joseph N. Merrett
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Patent number: 7485514Abstract: A MESFET and method for fabricating a MESFET are provided. The method includes forming an n-type channel portion in a substrate and forming a p-type channel portion in the substrate. A boundary of the n-type channel portion and a boundary of the p-type channel portion define an intrinsic region in the substrate.Type: GrantFiled: January 5, 2006Date of Patent: February 3, 2009Inventor: Thomas A. Winslow