Vertical (i.e., Where The Source Is Located Above The Drain Or Vice Versa) Patents (Class 257/135)
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Publication number: 20020001905Abstract: The present invention provide a vertical nano-sized transistor using carbon nanotubes capable of achieving high-density integration, that is, tera-bit scale integration, and a manufacturing method thereof, wherein in the vertical nano-sized transistor using carbon nanotubes, holes having diameters of several nanometers are formed in an insulating layer and are spaced at intervals of several nanometers. Carbon nanotubes are vertically aligned in the nano-sized holes by chemical vapor deposition, electrophoresis or mechanical compression to be used as channels. A gate is formed in the vicinity of the carbon nanotubes using an ordinary semiconductor manufacturing method, and then a source and a drain are formed at lower and upper parts of each of the carbon nanotubes thereby fabricating the vertical nano-sized transistor having an electrically switching characteristic.Type: ApplicationFiled: June 27, 2001Publication date: January 3, 2002Inventors: Won-bong Choi, Jo-won Lee, Young-hee Lee
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Publication number: 20010011729Abstract: A method of fabricating a self-aligned bipolar junction transistor in a semiconductor structure having a first layer of silicon carbide generally having a first conductivity type and a second layer of silicon carbide generally having a second conductivity type, opposite to the first conductivity type. The method comprises forming a pillar in the second silicon carbide layer, the pillar having a side wall and defining an adjacent horizontal surface on the second layer, forming a dielectric layer having a predetermined thickness on the second semiconductor layer, including the side wall and the horizontal surface. After formation of the dielectric layer, the dielectric layer on a portion of the horizontal surface adjacent the side wall is anisotropically etched while at least a portion of the dielectric layer remains on the side wall, thereby exposing a portion of the horizontal surface.Type: ApplicationFiled: February 19, 2001Publication date: August 9, 2001Inventors: Ranbir Singh, Anant K. Agarwal, Sei-Hyung Ryu
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Patent number: 6265735Abstract: A pin diode is formed by a p+ collector region, an n type buffer region, an n− region and an n+ cathode region. A trench is formed from the surface of n+ cathode region through n+ cathode region to reach n− region. An insulating film is formed along an inner wall surface of trench. A gate electrode layer is formed to oppose to the sidewall of n+ cathode region with insulating film interposed. A cathode electrode is formed to be electrically connected to n+ cathode region. An anode electrode is formed to be electrically connected to p+ collector region. The n+ cathode region is formed entirely over the surface between trenches extending parallel to each other. Thus, a power semiconductor device in which gate control circuit is simplified and which has good on property can be obtained.Type: GrantFiled: December 30, 1998Date of Patent: July 24, 2001Assignee: Mitsubishi Denki Kabushiki KaishaInventors: Tetsuo Takahashi, Katsumi Nakamura, Tadaharu Minato, Masana Harada
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Patent number: 6259134Abstract: A MOS-controllable power semiconductor trench device has a gate in the form of a trench which extends through a region of p type silicon into an n type region of low conductivity. A discontinous buried p layer below the bottom of the trench forms part of a thyristor which in operation is triggered into conduction by conduction of a PIN diode which is produced when an accumulation layer is formed in the n type region adjacent to the trench under the action of an on-state gate signal. The device has a high on-state conductivity and is protected against high voltage breakdown in its off-state by the presence of the buried layer. An off-state gate signal causes removal of the accumulation layer and conduction of the PIN diode and the thyristor ceases in safe, reliable and rapid manner.Type: GrantFiled: July 9, 1998Date of Patent: July 10, 2001Assignee: Mitel Semiconductor LimitedInventors: Gehan A. J Amaratunga, Florin Udrea
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Patent number: 6144066Abstract: The present invention relates to a structure for ground connection on a component including a vertical MOS power transistor and logic components, the substrate of a first type of conductivity of the component corresponding to the drain of the MOS transistor and the logic components being formed in at least one well of the second type of conductivity and on the upper surface side of the substrate. In the logic well, a region of the first type of conductivity is formed, on which is formed a metallization, to implement, on the one hand, an ohmic contact, and on the other hand, a rectifying contact.Type: GrantFiled: June 9, 1998Date of Patent: November 7, 2000Assignee: SGS-Thomson Microelectronics S.A.Inventor: Isabelle Claverie
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Patent number: 6137124Abstract: A vertical semiconductor component has an integrated switching device, which delivers an electric value correlating with the rear potential. The semiconductor component includes a doping region with a hole, which is free of the doping atoms of the doping region. The hole, when properly sized and contacted, can supply an electric current correlating with the rear potential.Type: GrantFiled: November 3, 1997Date of Patent: October 24, 2000Assignee: Robert Bosch GmbHInventors: Hartmut Michel, Peter Flohrs, Christian Pluntke, Alfred Goerlach, Anton Mindl, Ning Qu
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Patent number: 6137129Abstract: A pair of directly coupled Field Effect transistors (FETs), a latch of directly coupled FETS, a Static Random Access Memory (SRAM) cell including a latch of directly coupled FETs and the process of forming the directly coupled FET structure, latch and SRAM cell. The vertical FETs, which may be both PFETs, NFETs or one of each, are epi-grown NPN or PNP stacks separated by a gate oxide, SiO.sub.2. Each device's gate is the source or drain of the other device of the pair. The preferred embodiment latch includes two such pairs of directly coupled vertical FETs connected together to form cross coupled invertors. A pass gate layer is bonded to one surface of a layer of preferred embodiment latches to form an array of preferred embodiment SRAM cells. The SRAM cell may include one or two pass gates. The preferred embodiment SRAM process has three major steps. First, preferred embodiment latches are formed in an oxide layer on a silicon wafer.Type: GrantFiled: January 5, 1998Date of Patent: October 24, 2000Assignee: International Business Machines CorporationInventors: Claude L. Bertin, John E. Cronin, Erik L. Hedberg, Jack A. Mandelman
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Patent number: 6124605Abstract: An insulated gate bipolar transistor (IGBT) with latch-up protection includes a plurality of base layers of a first conductive type with upper and lower sides, a plurality of base regions of a second conductive type embedded in the upper side of the base layer, a plurality of source regions of the first conductive type embedded in the a plurality of base regions, a gate electrode formed over the base layer, an insulating layer formed between the gate electrode and the base layer, and a main electrode connected to the source region and the base regions. The gate electrode is formed into an elongated curved line with concave and convex parts. Each of the source regions includes a primary source region and plurality of projections. The primary source regions are formed on both sides of the gate electrode such that an intermediate area is formed adjacent to the source regions in each of the base regions and under the gate electrode.Type: GrantFiled: August 6, 1998Date of Patent: September 26, 2000Assignee: Samsung Electronics Co., Ltd.Inventor: Kyoung-Wook Seok
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Patent number: 6091108Abstract: A semiconductor device of SiC is adapted to hold high voltages in the blocking state thereof. The device comprises two parts (1, 2) each comprising one or more semiconductor layers of SiC and connected in series between two opposite terminals of the device, namely a sub-semiconductor device (1) able to withstand only low voltages in the blocking state thereof and a voltage-limiting part (2) able to withstand high voltages in the blocking state of the device and adapted to protect said sub-semiconductor device by taking a major part of the voltage over the device in the blocking state thereof.Type: GrantFiled: November 17, 1997Date of Patent: July 18, 2000Assignee: ABB Research Ltd.Inventors: Christopher Harris, Bo Bijlenga, Lennart Zdansky, Ulf Gustafsson, Mietek Bakowski, Andrey Konstantinov
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Patent number: 6084254Abstract: A lateral bipolar field effect transistor having a drift region of a first conductivity formed on a silicon-on insulation substrate with a buried insulation layer, a gate region of a second conductivity formed over and from the buried insulation layer separated by a channel depth, in the drift region, a source region of the first conductivity contacting with the gate region and formed on the buried insulation layer, and a drain region of the first conductivity opposite to the source region, the drain region separated from the gate region by a selected distance. The gate region comprises a plurality of cells arranged parallel to an extension of the source region, each cell separated from adjacent cell by a channel width.Type: GrantFiled: June 26, 1998Date of Patent: July 4, 2000Assignee: Hyundai Electronics Industries Co., Ltd.Inventor: Seong Dong Kim
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Patent number: 6057577Abstract: The present invention relate to a device of protection against voltage gradients of a monolithic component including a vertical MOS power transistor and logic circuits. The protection circuit has an N-type substrate corresponding to the drain of the MOS transistor, and logic components being realized in at least one P-type well formed in the upper surface of the substrate. Each of the N-type regions connected to the ground of the logic circuit, or to a node of low impedance with respect to the ground, is in series with a resistor.Type: GrantFiled: May 27, 1998Date of Patent: May 2, 2000Assignee: STMicroelectronics S.A.Inventors: Jean Barret, Antoine Pavlin, Pietro Fichera
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Patent number: 6051850Abstract: Methods of forming power semiconductor devices having insulated gate bipolar transistor cells and freewheeling diodes cells therein includes the steps of forming an array of emitter regions of second conductivity type (e.g., P-type) in a cathode layer of first conductivity type (e.g., N-type) and then forming a base region of first conductivity type on the cathode layer. An insulated gate electrode(s) pattern is then formed on a surface of the base region and used as an implant mask for forming interleaved arrays of collector and anode regions of second conductivity type in the base region. An array of source regions of first conductivity type is then formed in the collector regions, but not the anode regions, by implanting/diffusing source region dopants into the collector regions. To achieve preferred device characteristics, the array of collector regions is formed to be diametrically opposite the array of emitter regions to thereby define a plurality of vertical IGBT cells.Type: GrantFiled: October 10, 1997Date of Patent: April 18, 2000Assignee: Fairchild Korea Semiconductor Ltd.Inventor: Jae-Hong Park
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Patent number: 6008519Abstract: A vertical transistor (70) comprising a first semiconductor layer (14) of a first conductive type. A gate structure (32) of a second conductive type disposed on the first semiconductor layer (14). The gate structure (32) may include a plurality of gates (38) separated by channels (40). A second semiconductor layer (50) of the first conductive type may be disposed over the gate structure (32) and in the channels (40). An arresting element (36) may be disposed between and upper surface of the gates (38) and the second semiconductor layer (50). A void (52) may be formed in the second semiconductor layer (50) over the gate (38).Type: GrantFiled: December 15, 1997Date of Patent: December 28, 1999Assignee: Texas Instruments IncorporatedInventors: Han-Tzong Yuan, Donald L. Plumpton, Jau-Yuann Yang, Tae S. Kim
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Patent number: 5977570Abstract: A pin diode is formed by a p.sup.+ collector region, an n type buffer region, an n.sup.- region and an n.sup.+ cathode region. A trench is formed from the surface of n.sup.+ cathode region through n.sup.+ cathode region to reach n.sup.- region. An insulating film is formed along an inner wall surface of trench. A gate electrode layer is formed to oppose to the sidewall of n.sup.+ cathode region with insulating film interposed. A cathode electrode is formed to be electrically connected to n.sup.+ cathode region. An anode electrode is formed to be electrically connected to p.sup.+ collector region. The n.sup.+ cathode region is formed entirely over the surface between trenches extending parallel to each other. Thus, a power semiconductor device in which gate control circuit is simplified and which has good on property can be obtained.Type: GrantFiled: July 18, 1996Date of Patent: November 2, 1999Assignee: Mitsubishi Denki Kabushiki KaishaInventors: Tetsuo Takahashi, Katsumi Nakamura, Tadaharu Minato, Masana Harada
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Patent number: 5914503Abstract: An insulated gate thyristor is provided in which an inversion layer is created beneath a gate electrode to which a voltage is applied. An emitter region of a first conductivity type is biased to the same potential as a first main electrode via a MOSFET channel, and a thyristor portion consisting of the emitter region, a second base region of a second conductivity type, a base layer of the first conductivity type and an emitter layer of the second conductivity type is turned on. As electrons are injected uniformly from the entire emitter region, the insulated gate thyristor quickly shifts to the thyristor mode, and the on-voltage of the insulated gate thyristor of the invention is lowered. The insulated gate thyristor of the invention does not require a hole current that flows through the second base region of a convention EST in the Z-direction. In turning off, the pn junction recovers quickly without causing current localization, and the breakdown withstand capability if improved.Type: GrantFiled: February 13, 1997Date of Patent: June 22, 1999Assignee: Fuji Electric Co., Ltd.Inventors: Noriyuki Iwamuro, Yuichi Harada
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Patent number: 5900652Abstract: A method and apparatus for the localized reduction of the lifetime of charge carriers in integrated electronic devices. The method comprises the step of implanting ions, at a high dosage and at a high energy level, of a noble gas, preferably helium, in the active regions of the integrated device so that the ions form bubbles in the active regions. A further thermal treatment is performed after the formation of bubbles of the noble gas in order to improve the structure of the bubbles and to make the noble gas evaporate, leaving cavities in the active regions.Type: GrantFiled: July 25, 1995Date of Patent: May 4, 1999Assignee: Consorzio per la Ricerca sulla Microelettronica nel MezzogiornoInventors: Anna Battaglia, Piergiorgio Fallica, Cesare Ronsisvalle, Salvatore Coffa, Vito Raineri
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Patent number: 5847417Abstract: A normally-off semiconductor device with gate regions formed in a high-quality base is manufactured by forming a P.sup.+ layer in a lower surface of an N.sup.- substrate, selectively forming P.sup.+ gate regions in an upper surface of the N.sup.- substrate, forming intergate P.sup.+ regions in the upper surface of the N.sup.- substrate between the P.sup.+ gate regions, forming an N.sup.+ layer in an upper surface of an N.sup.- substrate, joining the N.sup.- substrate and the N.sup.- substrate to each other by heating them at about 800.degree. C. in a hydrogen atmosphere while the upper surface of the N.sup.- substrate and a lower surface of the N.sup.- substrate are being held against each other, and forming an anode electrode and a cathode electrode.Type: GrantFiled: August 17, 1995Date of Patent: December 8, 1998Assignee: NGK Insulators, Ltd.Inventor: Yoshio Terasawa
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Patent number: 5831289Abstract: A silicon carbide gate turn off thyristor (GTO) has a silicon carbide junction field effect transistor (JFET) connected between the gate of the GTO and one of its anode or cathode electrodes thereby minimizing cooling requirements while providing for rapid switching.Type: GrantFiled: October 6, 1997Date of Patent: November 3, 1998Assignee: Northrop Grumman CorporationInventor: Anant Agarwal
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Patent number: 5773851Abstract: An n-drift region, a p-base region, and an n-emitter region are formed in a semiconductor substrate. A trench is formed to be in contact with n-emitter region and p-base region, and a gate electrode is formed in trench with an insulated gate layer interposed. A first metal electrode layer electrically connected to n-emitter region, and a second metal electrode layer electrically connected to p-base region are provided. A direct current power source apparatus is connected to first and second metal electrode layers. Accordingly, on-state voltage can be reduced.Type: GrantFiled: June 11, 1997Date of Patent: June 30, 1998Assignee: Mitsubishi Denki Kabushiki KaishaInventors: Hideki Nakamura, Tadaharu Minato
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Patent number: 5729031Abstract: A p type collector region is formed at the side of collector surface of an n.sup.- region with an n type buffer region. This p type collector region has a structure including a p type impurity region and a p.sup.+ impurity region. Impurity concentrations of the p type impurity region, the p.sup.30 impurity region and the n type buffer region are of a prescribed relationship, and the diffusion depth of the p type impurity region from the collector surface is not lower than 2.0 .mu.m. Thus, a semiconductor device in which turn-off loss is sufficiently low and which is not likely to be affected by thermal treatment upon formation of each of the impurity V regions can be obtained.Type: GrantFiled: July 10, 1996Date of Patent: March 17, 1998Assignee: Mitsubishi Denki Kabushiki KaishaInventor: Akio Uenishi
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Patent number: 5689127Abstract: A vertical double-gate field effect transistor includes a source layer, an epitaxial channel layer and a drain layer arranged in a stack on a bulk or SOI substrate. The gate oxide is thermally grown on the sides of the stack using differential oxidation rates to minimize input capacitance problems. The gate wraps around one end of the stack, while contacts are formed on a second end. An etch-stop layer embedded in the second end of the stack enables contact to be made directly to the channel layer.Type: GrantFiled: March 5, 1996Date of Patent: November 18, 1997Assignee: International Business Machines CorporationInventors: Jack Oon Chu, Louis Lu-Chen Hsu, Jack Allan Mandelman, Yuan-Chen Sun, Yuan Taur
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Patent number: 5689121Abstract: An insulated-gate semiconductor device comprises a P type emitter layer, an N.sup.- high-resistive base layer formed on the P type emitter layer, and a P type base layer contacting the N.sup.- high-resistive base layer. A plurality of trenches are formed having a depth to reach into the N.sup.- high-resistive base layer from the P type base layer. A gate electrode covered with a gate insulation film is buried in each trench. An N type source layer to be connected to a cathode electrode is formed in the surface of the P type base layer in a channel region between some trenches, thereby forming an N channel MOS transistor for turn-on operation. A P channel MOS transistor connected to the P base layer is formed in a channel region between other trenches so as to discharge the holes outside the device upon turn-off operation.Type: GrantFiled: June 7, 1995Date of Patent: November 18, 1997Assignee: Kabushiki Kaisha ToshibaInventors: Mitsuhiko Kitagawa, Ichiro Omura, Akio Nakagawa, Norio Yasuhara, Tomoki Inoue
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Patent number: 5663582Abstract: A recess-gate type static induction transistor having a high breakdown voltage is provided, which includes an n-type channel region provided over an n.sup.+ -type drain region, p.sup.+ -type elongated gate regions provided in grooves of the channel region, n.sup.+ -type elongated regions formed on the channel region so as to be arranged in parallel with the gate regions, each of which is disposed between the gate regions, and a p.sup.+ -type guard ring region provided in the channel region and arranged to surround the gate regions. The elongated gate regions are coupled to the guard ring region at both edges. In addition, the outer-most elongated gate regions are coupled to the guard ring region along the longitudinal direction, respectively, thereby increasing the breakdown voltage of the device.Type: GrantFiled: May 21, 1996Date of Patent: September 2, 1997Assignee: Zaidan Hojin Handotai Kenkyu ShinkokaiInventors: Junichi Nishizawa, Kaoru Motoya, Akira Ito
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Patent number: 5648664Abstract: A BIFET vacuum tube replacement structure includes a plurality of devices that replicate the characteristics of a vacuum tube. The vacuum tube replacement structure has the same pin-out as the vacuum tube being replaced and so can be exchanged directly for a vacuum tube in an audio amplifier. The vacuum tube replacement structure is suitable for use in a wide range of audio amplifier applications without modification to the audio amplifiers. Further, there is no noticeable degradation to the human ear in the sound quality when the vacuum tube replacement structure is used in an audio amplifier in place of a vacuum tube. A unitary device that is a combination of a high impedance bipolar like transistor and a unipolar junction field effect transistor, that is referred to as a BIFET, is used in the vacuum tube replacement structure. In one embodiment, the bipolar like transistor is formed in combination with the gate of the unipolar junction field effect transistor.Type: GrantFiled: January 20, 1995Date of Patent: July 15, 1997Inventors: J. Kirkwood H. Rough, Adrian I. Cogan, Neill R. Thornton
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Patent number: 5619047Abstract: A diode (1) is specified which has electron injection means on the anode-side principal surface (3). After the reverse-current peak has been traversed, said means inject electrons into the anode emitter. This compensates for holes and the danger of a dynamic field overshoot, which may result in an avalanche breakdown, is reduced. The electron injection means preferably comprise an n-channel MOS cell. High voltages and high dI/dt values can be safely handled with a diode according to the invention. A diode in accordance with the invention is preferably used as freewheeling diode in a converter circuit arrangement.Type: GrantFiled: September 12, 1995Date of Patent: April 8, 1997Assignee: Asea Brown Boveri AGInventor: Friedhelm Bauer
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Patent number: 5608235Abstract: A voltage-controlled power monolithic bidirectional switch has two main terminals and includes a control electrode whose voltage is referenced to one of the main terminals. The switch includes a lateral P-channel MOS transistor; a vertical N-channel MOS transistor, the source well of the vertical N-channel MOS transistor also constituting the source of the lateral transistor; a lateral thyristor whose first three regions correspond to the source, drain and channel of the lateral MOS transistor; a first vertical thyristor disposed in parallel with the lateral thyristor; and a second vertical thyristor having a polarity opposite to the first polarity and disposed in parallel with the vertical MOS transistor.Type: GrantFiled: November 7, 1994Date of Patent: March 4, 1997Assignee: SGS-Thomson Microelectronics S.A.Inventor: Robert Pezzani
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Patent number: 5585651Abstract: An insulated-gate semiconductor device comprises a p type emitter layer, an N.sup.- high-resistive base layer formed on the P type emitter layer, and a P type base layer contacting the N.sup.- high-resistive base layer. A plurality of trenches are formed having a depth to reach into the N.sup.- high-resistive base layer from the P type base layer. A gate electrode covered with a gate insulation film is buried in each trench. An N type source layer to be connected to a cathode electrode is formed in the surface of the P type base layer in a channel region between some trenches, thereby forming an N channel MOS transistor for turn-on operation. A P channel MOS transistor connected to the P base layer is formed in a channel region between other trenches so as to discharge the holes outside the device upon turn-off operation.Type: GrantFiled: June 7, 1995Date of Patent: December 17, 1996Assignee: Kabushiki Kaisha ToshibaInventors: Mitsuhiko Kitagawa, Ichiro Omura, Akio Nakagawa, Norio Yasuhara, Tomoki Inoue
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Patent number: 5574297Abstract: In order to compatibly implement improvement in withstand voltage and ON-state resistance as well as reduction in turnon loss and improvement in di/dt resistance, an n buffer layer (12) is locally exposed on a lower surface of a semiconductor substrate (160), while a polysilicon additional resistive layer (104) is formed to cover the exposed surface. An anode electrode (101) covering the lower surface of the semiconductor substrate (160) is connected to a p emitter layer (11) and the additional resistive layer (104). Thus, the n buffer layer (12) and the anode electrode (101) are connected with each other through the additional resistive layer (104), whereby a gate trigger current is reduced. Thus, turnon loss is reduced and di/dt resistance is increased. At the same time, the withstand voltage and the ON-state resistance are excellent due to provision of the n buffer layer (12).Type: GrantFiled: March 21, 1995Date of Patent: November 12, 1996Assignee: Mitsubishi Denki Kabushiki KaishaInventors: Nozomu Sennenbara, Kouji Niinobu, Kazuhiko Niwayama, Futoshi Tokunoh
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Patent number: 5559355Abstract: Mutual interference is reduced between a main cell portion and a sensing cell portion for detecting the current flowing through the main cell portion of a vertical MOS semiconductor device, and accuracy and reliability of overcurrent detection are improved. In the device, well regions of (p) type are formed between the main and sensing cell portions for capturing the minority carriers. Breakdown of the gate oxide film caused by an open emitter electrode of the sensing cell portion is prevented by forming the (p) type well regions with ring shapes, by spacing the (p) type well regions by 5 to 20 .mu.m, and by adjusting the isolation withstand voltage between the main and sensing cell portions below the withstand voltage of the gate oxide film. A voltage spike is minimized by narrowing the overlap of the detecting and gate electrodes for reduced capacitance between these electrodes.Type: GrantFiled: June 20, 1995Date of Patent: September 24, 1996Assignee: Fuji Electric Co., Ltd.Inventors: Tomoyuki Yamazaki, Shigeyuki Obinata, Masahito Otsuki, Seiji Momota, Tatsuhiko Fujihira
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Patent number: 5541424Abstract: An electronic component especially a p-channel or n-channel permeable base transistor (PBT) is provided as a plurality of layers, fabricated in a laminated composite, and with at least one laterally structured layer provided for controlling a space charge zone, especially a base of the electronic component.Type: GrantFiled: July 23, 1994Date of Patent: July 30, 1996Assignee: Forschungszentrum Julich GmbHInventor: Jurgen Graber
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Patent number: 5508534Abstract: A semiconductor device including a layer formed without being affected by a stepped ground pattern and a method of fabricating the semiconductor device are disclosed. Cap portions (30) (insulating layers) formed over trenches (13) and covering doped polysilicon (5) have an inclined surface (26) which satisfies Y/X .ltoreq.5 where X is the length of the inclined surface (26) in a direction of the surface of a body (50) and Y is the height of the inclined surface (26) from the surface of the body (50). Formation of the insulating layers having the smooth inclined surface satisfying Y/X.ltoreq.5 permits a first main electrode to be formed non-defectively without being affected by the ground pattern including the insulating layers.Type: GrantFiled: February 7, 1995Date of Patent: April 16, 1996Assignee: Mitsubishi Denki Kabushiki KaishaInventors: Katsumi Nakamura, Tadaharu Minato, Shuuichi Tominga, Katsuomi Shiozawa
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Patent number: 5426314Abstract: A static induction thyristor has a first semiconductor area having a high impurity concentration of a first conductivity type. A second semiconductor area having low impurity concentration is formed adjacent to the first semiconductor area. A third semiconductor area having a high impurity concentration of a second conductivity type which is the conductivity type opposite to the first conductivity type is formed on a part of a surface of the second semiconductor area so located as to form a fourth semiconductor area located within the third semiconductor area. A fifth semiconductor area having a high impurity concentration of the first conductivity type is formed on the part of the surface of the second semiconductor area in spaced relation to the forth semiconductor area.Type: GrantFiled: April 21, 1994Date of Patent: June 20, 1995Assignee: Zaidan Hojin Handotai Kenkyu ShinkokaiInventors: Jun-ichi Nishizawa, Sohbe Suzuki
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Patent number: 5367189Abstract: A semiconductor device comprises a first electrode buried in one main face of a substrate and surrounded by a first insulator, a field oxide film covering the surface of the first electrode, a semiconductor layer connected with the first electrode, a second insulator covering the surface of the semiconductor layer, a second electrode connected with the semiconductor layer, a gate electrode connected with the semiconductor layer between the second insulator and the field oxide film, and an outgoing electrode connected with the first electrode.Type: GrantFiled: November 4, 1992Date of Patent: November 22, 1994Assignee: Fujitsu LimitedInventor: Shunji Nakamura
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Patent number: 5341003Abstract: A MOS semiconductor device is disclosed for monitoring the value of the current flowing through an element by outputting a sense signal. The semiconductor has a main unit element and a sense unit element formed in a semiconductor layer, and the current flowing through the sense unit element is proportional to the current flowing through the main unit element. Both the main unit element and the sense unit element have a base region, a source region, a gate electrode, and a source electrode. A doped region of the same conductivity type as the base regions is formed in the semiconductor layer between the base regions of the main unit element and the sense unit element. This doped region is in contact with the source electrode of the main unit element. This structure decreases the power loss due to the sense signal current and ensures a linear relationship between the sense signal current and the main current.Type: GrantFiled: June 9, 1992Date of Patent: August 23, 1994Assignee: Fuji Electric Co., Ltd.Inventor: Shigeyuki Obinata
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Patent number: 5319221Abstract: MOS-controlled thyristor is formed of a P-type first base layer (23), an N-type floating emitter layer (24), and a P-type second base layer (25) on an N.sup.- -type base layer (14), by a double diffusion process. The thyristor mode is realized early on and conduction in a parasitic thyristor is prevented by forming a source layer (17) in the second base layer (25) to restrict the current flowing through the second base layer (25). The semiconductor has high withstand voltage, low resistance over the entire device, suppresses the occurrence of discontinuity in the voltage-current curve, and is capable of suppressing the latch-up phenomenon and controlling large currents.Type: GrantFiled: September 14, 1992Date of Patent: June 7, 1994Assignee: Fuji Electric Co., Ltd.Inventor: Katsunori Ueno
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Patent number: 5304822Abstract: A static induction type semiconductor device of a surface gate type, includes a source region, gate region and drain region. A channel region is formed between the drain region and the source region, such that when a bias potential is applied between the gate region and the source region, carriers flow to the drain region from the source region via the channel region. A source electrode is provided on the semiconductor layer. A source contact region is provided between the source electrode and the source region to establish electrical connection therebetween. The source contact region is segmented into a plurality of smaller regions or sections whose total area is smaller than the area of the corresponding portion of the source region, for improving the current gain, and for preventing or significantly reducing local current concentration.Type: GrantFiled: May 1, 1992Date of Patent: April 19, 1994Assignees: Kabushiki Kaisha Toyoda Jidoshokki Seisakusho, Kabushiki Kaisha Toyota Chuo KenkyushoInventors: Haruo Takagi, Shinobu Aoki, Yukihiko Watanabe, Hiroshi Tadano
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Patent number: 5298769Abstract: A GTO thyristor includes a p-type emitter layer, an n-type base layer, a p-type base layer and an n-type emitter layer. An additional n-type layer is formed on the p-type base layer next to the n-type emitter layer An additional p.sup.+ -type layer is formed on the additional n-type layer and stretches to the n-type emitter layer. An anode electrode and a cathode electrode are disposed respectively on the n-type emitter layer and the p-type base layer. The n-type emitter layer and the additional p.sup.+ -type layer are connected with each other by a floating electrode. A first gate electrode is disposed on the additional p.sup.+ -type layer, additional n-type layer and p-type base layer with an insulating film interposed therebetween so as to form a first FET. A second gate electrode is disposed on the n-type base layer, p-type base layer and n-type emitter layer with an insulating film interposed therebetween so as to form a second FET.Type: GrantFiled: March 31, 1993Date of Patent: March 29, 1994Assignee: Kabushiki Kaisha ToshibaInventors: Ichiro Omura, Mitsuhiko Kitagawa
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Patent number: 5243201Abstract: In an MOS-controlled thyristor MCT comprising a multiplicity of adjacently disposed individual MCT cells (MC) having a cell width and which are electrically connected in parallel, either the MCT cells (MC) themselves or cell clusters (15) comprising a few closest-packed MCT cells (MC) are mutually separated by nonemitting gaps (2) which do not inject charge carriers into the cathode base layer and which have lateral linear dimensions greater than or at least equal to the cell width of the MCT cells (MC). As a result of this separation, the full performance of the individual MCT cell (MC) is achieved even in large-area components containing many cells.Type: GrantFiled: August 11, 1992Date of Patent: September 7, 1993Assignee: Asea Brown Boveri Ltd.Inventor: Friedhelm Bauer
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Patent number: 5168333Abstract: A semiconductor device including a semiconductive substrate having first and second opposite surfaces; a thyristor formed on the substrate and including a base layer formed in the first surface of the substrate, a first emitter layer formed in the base layer, a conductive layer electrically connected to the emitter layer to serve as a cathode electrode, a first gate electrode connected to the base layer, a second emitter layer formed in the second surface of the substrate, a drain layer formed in the second emitter layer, a conductive layer for electrically connecting the second emitter layer with said drain layer and for serving as an anode electrode of said thyristor. A metal oxide semiconductor field effect transistor is provided to accelerate the flow of carriers in said thyristor to the anode electrode to turn off said thyristor.Type: GrantFiled: February 28, 1991Date of Patent: December 1, 1992Assignee: Kabushiki Kaisha ToshibaInventors: Akio Nakagawa, Yoshihiro Yamaguchi, Kiminori Watanabe