In Vertical-walled Groove Patents (Class 257/397)
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Patent number: 5977590Abstract: An n.sup.- well region is formed at a surface of a semiconductor substrate. A MOS transistor of high breakdown voltage having a drain region and a source region is formed at the surface of the n.sup.- well region. The n.sup.- well region has an impurity concentration peak right below the drain region. Accordingly, a semiconductor device having a high breakdown voltage insulation gate type field effect transistor that can suppress increase of a depletion layer when high voltage is applied across the drain, that can reduce the electric field intensity across the drain, and that has superior breakdown voltage, and a fabrication method thereof, are obtained.Type: GrantFiled: July 10, 1998Date of Patent: November 2, 1999Assignee: Mitsubishi Denki Kabushiki KaishaInventor: Seiji Suzuki
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Patent number: 5969393Abstract: A semiconductor device comprises a semiconductor substrate having a major surface, a semiconductor region defined between at least two trenches formed in the major surface, a first insulating layer formed on at least side walls of each of the trenches, and a second insulating layer formed in a predetermined area of the surface of the semiconductor region to contact the first insulating layer. The thickness of the first insulating layer at the top of the side walls is set larger than the thickness of the second insulating layer.Type: GrantFiled: September 11, 1996Date of Patent: October 19, 1999Assignee: Kabushiki Kaisha ToshibaInventor: Mitsuhiro Noguchi
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Patent number: 5949116Abstract: A MOS device and method of fabricating the same, wherein the source/drain region has polysilicon trench structure which are formed by self-alignment using silicon oxide layers as masks. The source/drain regions extend to the field oxide layer and/or above the gate. Therefore, contacts can be formed on source/drain conductive regions above the field oxide layer.Type: GrantFiled: July 7, 1997Date of Patent: September 7, 1999Assignee: United Microelectronics Corp.Inventor: Jemmy Wen
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Patent number: 5937287Abstract: The present invention relates to the formation of trench isolation structures that isolate active areas and a preferred doping in the fabrication of a CMOS device with a minimized number of masks. Ions of a P-type dopant are implanted into a semiconductor substrate having therein a P-well and an N-well. Each of the N-well and P-well has therein a trench. The ions of the P-type dopant are implanted beneath each of the trenches in the P-well and the N-well to create a first P-type dopant concentration profile in the semiconductor substrate, wherein the P-well and the N-well are substantially unimplanted by the ions of the P-type dopant in active areas adjacent to the respective trenches therein. A second implanting ions of a P-type dopant is made into the semiconductor substrate. The second implanting is beneath each of the trenches in the P-well and the N-well to form a second P-type dopant concentration profile.Type: GrantFiled: July 22, 1997Date of Patent: August 10, 1999Assignee: Micron Technology, Inc.Inventor: Fernando Gonzalez
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Patent number: 5905285Abstract: A field effect transistor comprising a semiconductor substrate having a transistor trench extending downward from an upper surface of the semiconductor substrate. The trench extends to a trench depth below an upper surface of the semiconductor substrate. The transistor further includes a gate dielectric layer that is formed on a floor of the transistor trench over a channel region of the semiconductor substrate. A conductive gate structure is formed above and in contact with the gate dielectric layer. A source/drain impurity distribution is formed within a source/drain region of the semiconductor substrate. The source/drain region is laterally disposed on either side of the channel region of the semiconductor substrate. In a preferred embodiment, the trench depth is between 1,000-5,000 angstroms and a thickness of the conductive gate structure is less than 5,000 angstroms such that an upper surface of the conductive gate structure is level with or below an upper surface of the semiconductor substrate.Type: GrantFiled: February 26, 1998Date of Patent: May 18, 1999Assignee: Advanced Micro Devices, Inc.Inventors: Mark I. Gardner, Fred N. Hause
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Patent number: 5886382Abstract: A method for forming a trench transistor structure begins by forming a buried layers (12 and 16) and a doped well (22) in a substrate (10) via epitaxial growth processing. A trench region (24) is then etched into the substrate (10) to expose a the layer (12). A conductive sidewall spacer (28) is formed within the trench (24) as a gate electrode. The spacer (28) gates a first transistor (12, 28, 32) located adjacent a first half of the trench (24) and a second transistor (12, 28, 34) located adjacent a second half of the trench (24). Region (12) is a common electrode wherein the channel regions of both the first and second transistor are coupled in a serial manner through the region (12).Type: GrantFiled: July 18, 1997Date of Patent: March 23, 1999Assignee: Motorola, Inc.Inventor: Keith E. Witek
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Patent number: 5866934Abstract: An improved series and/or parallel connection of transistors within a logic gate is presented. The improved connection is brought about by a sacrificial structure on which gate conductors are formed adjacent sidewall surfaces of the sacrificial structure. The sacrificial structure thereby provides spacing between the series-connected or parallel-connected transistors. Upon removal of each sacrificial structure, a pair of transistors can be formed by implanting dopant species into the substrate on opposite sides of the spaced conductors. Beneath what was once a sacrificial structure is a shared implant area to which two transistors are coupled either in series or in parallel. By depositing the gate conductor material and then anisotropically removing the material except adjacent the vertical sidewall surfaces, an ultra short gate conductor can be formed concurrent with other gate conductors within a logic gate.Type: GrantFiled: June 20, 1997Date of Patent: February 2, 1999Assignee: Advanced Micro Devices, Inc.Inventors: Daniel Kadosh, Mark I. Gardner, Jon D. Cheek
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Patent number: 5854503Abstract: A structure and method of maximizing the volume of low dielectric constant material between adjacent traces of a conductive interconnect structure. A semiconductor structure includes a semiconductor substrate, a first insulating layer located over the semiconductor substrate, a conductive interconnect layer having a plurality of conductive traces located over the first insulating layer, and a patterned insulating layer located over the patterned interconnect layer. One or more trenches are formed in the upper surface of the first insulating layer. These trenches, which do not extend completely through the first insulating layer, are located between adjacent traces of the interconnect layer. A dielectric material having a low dielectric constant is located in these trenches, and between adjacent traces of the patterned interconnect layer. The trenches advantageously maximize the volume of low dielectric constant material which is located between the traces.Type: GrantFiled: November 19, 1996Date of Patent: December 29, 1998Assignee: Integrated Device Technology, Inc.Inventors: Cheng-Chen Hsueh, Shih-Ked Lee, Chuen-Der Lien
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Patent number: 5814895Abstract: In a static random access memory (SRAM), a memory cell ratio is increased without deteriorating an integration degree of this SRAM. The static random access memory is arranged by: trenches formed in a semiconductor substrate and an insulating layer for isolating elements within a memory cell forming region; one pair of word transistors; one pair of driver transistors for constituting a flip-flop by forming channel regions of the driver transistors in side surfaces of the trenches and by cross-connecting gate electrodes thereof and drain electrodes thereof at one pair of input/output terminals of the flip-flop; and one pair of word transistors connected between the one pair of input/output terminals of the flip-flop and a bit line.Type: GrantFiled: December 19, 1996Date of Patent: September 29, 1998Assignee: Sony CorporationInventor: Teruo Hirayama
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Patent number: 5804862Abstract: A MIS type field effect transistor has a source/drain region overlain by a titanium silicide layer contiguous to an upper silicon nitride layer of a buried isolating structure embedded into a silicon substrate, and a contact hole is formed in an inter-level insulating layer of silicon oxide exposing a part of the upper silicon nitride layer and a part of the titanium silicide layer into the contact hole; while the inter-level insulating layer is being selectively etched so as to form the contact hole, the upper silicon nitride layer serves as an etching stopper, and the contact hole never reaches the silicon substrate beneath the buried isolating structure.Type: GrantFiled: February 20, 1996Date of Patent: September 8, 1998Assignee: NEC CorporationInventor: Akira Matumoto
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Patent number: 5763931Abstract: A semiconductor device having the SOI structure is provided, which enables to reduce the size of components compared with the conventional semiconductor devices. The device contains a first insulator film formed on a semiconductor substrate, and semiconductor islands formed on the first insulator film. Each of the islands has an electronic component. The device further contains semiconductor sidewalls formed to surround the respective islands. The sidewalls are contacted with outer sides of the corresponding islands. Electrodes are formed outside the islands to be contacted with the corresponding sidewalls. A second insulator film is formed on the exposed first insulator film from the islands to laterally isolate the respective islands and the corresponding sidewalls from each other. The electronic components are electrically connected to the respective electrodes through the corresponding sidewalls.Type: GrantFiled: September 21, 1995Date of Patent: June 9, 1998Assignee: NEC CorporationInventor: Mitsuhiro Sugiyama
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Patent number: 5744847Abstract: This invention describes a device structure and a method of forming the device structure using trenches with sidewalls formed in the substrate of an integrated circuit. A highly doped polysilicon layer is formed on the walls of the trench or the trench is filled with highly doped polysilicon to form the source and drain of a field effect transistor in an integrated circuit. The invention provides reduced source and drain resistance. The capacitances between the gate and source and the gate and drain are reduced as well.Type: GrantFiled: September 2, 1997Date of Patent: April 28, 1998Assignee: United Microelectronics CorporationInventor: Jemmy Wen
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Patent number: 5721448Abstract: An integrated circuit with FETs having an essentially uniform gate oxide thickness and FETs having gate oxide thickness enhanced along the sides. FETs with enhanced gate oxide have an ONO layer diffused with potassium in close proximity to the enhanced (thicker) oxide, and, as a result, have a slightly higher V.sub.t and much more attenuated soft turn on.Type: GrantFiled: July 30, 1996Date of Patent: February 24, 1998Assignee: International Business Machines CorporationInventors: Manfred Hauf, Max G. Levy, Victor Ray Nastasi
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Patent number: 5717239Abstract: In a MOS transistor device, the gate width is effectively enlarged without increasing the occupied area of the transistor by forming a plurality of rectangular grooves in the direction perpendicular to the gate width, and filling in these rectangular grooves with a gate electrode. Since these grooves are formed by anisotropic etching, there is no risk of contaminating the wafer.Type: GrantFiled: November 15, 1996Date of Patent: February 10, 1998Assignee: NEC CorporationInventor: Takayuki Nagai
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Patent number: 5714781Abstract: A power MOSFET having a groove for forming a channel improved for shortening the switching time and increasing the dielectric breakdown strength of the gate oxide film is disclosed. The power MOSFET includes a concave structure in which a gate oxide film at a groove bottom is thickened. Namely, since the gate oxide film between a gate electrode and a first conductivity type semiconductor layer is thick, the capacitance of the oxide film therebetween is reduced. Therefore, the input and output capacitance of the gate oxide film can be reduced, and switching loss can be also reduced since the switching time can be shortened. Further, greater dielectric breakdown strength of the gate oxide film can be obtained as a result of the thickened gate oxide film at the groove bottom.Type: GrantFiled: April 26, 1996Date of Patent: February 3, 1998Assignee: Nippondenso Co., Ltd.Inventors: Tsuyoshi Yamamoto, Masami Naito, Takeshi Fukazawa
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Patent number: 5666311Abstract: Disclosed is a semiconductor memory device which has memory cell transistors each comprising a liner source diffusion layer, a land-shaped drain diffusion layer, a gate oxide film containing a floating gate formed on the channel region between those diffusion layers, and a control gate formed on the gate oxide film. Trenches are formed in the substrate in no contact with the channel regions to isolate the cell transistors from each other.Type: GrantFiled: June 6, 1995Date of Patent: September 9, 1997Assignee: Kabushiki Kaisha ToshibaInventor: Seiichi Mori
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Patent number: 5652458Abstract: The present invention discloses a structure of a transistor in a semiconductor device and a method of manufacturing the same.The present invention manufactures a high voltage transistor by etching a silicon substrate to a depth deeper than that of the field oxide film by a self-aligned wet etching process using the field oxide film as a mask and, thereafter, by forming the first gate electrode which electrically switches ON and OFF between the source region and the drain region by using a gate electrode mask and simultaneously forming a second gate electrode to prevent a junction breakdown below the bird's beak of the field oxide film.Accordingly, the present invention can improve the degree of integration of the device by forming a gate electrode to prevent a junction breakdown below the bird's beak of the field oxide film.Type: GrantFiled: July 2, 1996Date of Patent: July 29, 1997Assignee: Hyundai Electronics Co., Ltd.Inventor: Byung Jin Ahn
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Patent number: 5646888Abstract: Disclosed is a semiconductor memory device which has memory cell transistors each comprising a liner source diffusion layer, a land-shaped drain diffusion layer, a gate oxide film containing a floating gate formed on the channel region between those diffusion layers, and a control gate formed on the gate oxide film. Trenches are formed in the substrate in no contact with the channel regions to isolate the cell transistors from each other.Type: GrantFiled: February 25, 1994Date of Patent: July 8, 1997Assignee: Kabushiki Kaisha ToshibaInventor: Seiichi Mori
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Patent number: 5646052Abstract: A method of forming a semiconductor device by concurrently forming both single-trenched small field regions and double-trench-extension large field regions, and the device so formed.Type: GrantFiled: April 16, 1996Date of Patent: July 8, 1997Assignee: Goldstar Electron Co., Ltd.Inventor: Chang Jae Lee
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Patent number: 5614750Abstract: A buried layer contact for a integrated circuit structure is provided, with particular application for a contact for a buried collector of a bipolar transistor. The buried layer contact takes the form of a sinker comprising a fully recessed trench isolated structure having dielectric lined sidewalls and filled with conductive material, e.g. doped polysilicon which contacts the buried layer. The trench isolated contact is more compact than a conventional diffused sinker structure, and thus beneficially allows for reduced transistor area. Advantageously, a reduced area sinker reduces the parasitic capacitance and power dissipation. In a practical implementation, the structure provides for an annular collector contact structure to reduce collector resistance.Type: GrantFiled: June 29, 1995Date of Patent: March 25, 1997Assignee: Northern Telecom LimitedInventors: Joseph P. Ellul, John M. Boyd
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Patent number: 5600161Abstract: The present invention is a process for forming diffusion areas and field isolation regions on a silicon substrate, by the steps of: growing a field oxide layer on the surface of the substrate; forming a mask pattern which exposes a plurality of spaced-apart regions on the surface of the field oxide layer; removing portions of the field oxide layer in the exposed, spaced-apart regions with an anisotropic etch so as to leave a cavity in each spaced-apart region, each cavity having as its floor an exposed region of the silicon substrate, and having vertical walls of field oxide; angularly chamfering the rim of each cavity with a facet etch; and filling each cavity with silicon using selective epitaxial growth, and using the floor of each cavity as the seed crystal for such growth.Type: GrantFiled: March 24, 1995Date of Patent: February 4, 1997Assignee: Micron Technology, Inc.Inventors: Fernando Gonzalez, Angus C. Fox, III
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Patent number: 5598019Abstract: A trench for element isolation is formed on the main surface of a semiconductor substrate. A conductive layer is formed in the trench, electrically connected to the semiconductor substrate. Oxide films and a dielectric film is formed between the conductive layer and the sidewall of the trench. A field oxide film is formed on the conductive layer. The dielectric film extends from the sidewall of the field oxide film to a region between the sidewall of the trench and the conductive layer. Consequently, a semiconductor device having an element isolation structure of superior isolation capability and high reliability can be obtained.Type: GrantFiled: April 6, 1994Date of Patent: January 28, 1997Assignee: Mitsubishi Denki Kabushiki KaishaInventors: Shigeki Komori, Takehisa Yamaguchi
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Patent number: 5569949Abstract: A high voltage power transistor cell is developed that provides improved RDSon performance without sacrificing breakdown performance through utilization of trench based transistor technology. A source, drain and trench are formed within a substrate. A gate is formed or the surface over a spacing between the source and the trench. A drift region is formed around the trench. An isolation region may optionally be added allowing electrical isolation between the source and the substrate. The lateral current flow feature allows multiple high voltage power transistors, electrically isolated from one another, to exist on a single semiconductor chip. The drift region formed around the trench provides RESURF transistor characteristics without sacrificing die area.Type: GrantFiled: May 31, 1995Date of Patent: October 29, 1996Assignee: Texas Instruments IncorporatedInventor: Satwinder Malhi
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Patent number: 5548150Abstract: A high-resistant p-silicon layer is formed on a silicon substrate through a silicon oxide film. N-source and n-drain layers are selectively formed in the surface of the high-resistant p-silicon layer. A gate electrode is formed through a gate insulating film on a channel region between the source and drain layers. To induce an n-inverted layer under the gate electrode, a p-base layer is formed in the high-resistant p-silicon layer. A depletion layer extending from a pn junction between the n-drain layer and the high-resistant p-silicon layer reaches the silicon oxide film in a thermal equilibrium state. Part of the high-resistant p-silicon layer extends into a channel region between the drain and base layers. The drain and base layers are connected to each other through part of the depletion layer in the thermal equilibrium state. A field effect transistor having a high-speed operation is provided.Type: GrantFiled: April 17, 1995Date of Patent: August 20, 1996Assignee: Kabushiki Kaisha ToshibaInventors: Ichiro Omura, Akio Nakagawa, Tadashi Sakai, Masayuki Sekimura, Hideyuki Funaki
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Patent number: 5541427Abstract: A storage latch comprising a gate insulating layer over the substrate, shallow trenches formed through the insulating layer and in the substrate to provide device insulation; and doped regions in the substrate between the shallow trenches. The doped regions define sources and drains. Gate stacks are formed over regions of oxide adjacent the doped regions. A planarized insulator is formed between the gate stacks. Openings are provided in the planarized insulator for contacts to the doped regions and the gate stacks. Conductive material fills the openings to form contacts for the doped regions and for the gate stacks. A patterned layer of conductive material on the planarized insulator connects selected ones of the contacts for wiring portions of the latch.Type: GrantFiled: December 3, 1993Date of Patent: July 30, 1996Assignee: International Business Machines CorporationInventors: Barbara A. Chappell, Bijan Davari, George A. Sai-Halasz, Yuan Taur
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Patent number: 5539229Abstract: A semiconductor structure comprising a transistor having a gate conductor that has first and second edges bounded by raised isolation structures (e.g. STI). A source diffusion is self-aligned to the third edge and a drain diffusion is self-aligned to the fourth edge of the gate electrode.Type: GrantFiled: December 28, 1994Date of Patent: July 23, 1996Assignee: International Business Machines CorporationInventors: Wendell P. Noble, Jr, Ashwin K. Ghatalia, Badih El-Kareh
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Patent number: 5525824Abstract: A multi-channel type intelligent power IC which solves the problems of parasitic transistor and increase in an area of isolation region, both of which are inherent problem in a pn junction isolation substrate. The power IC also enhances heat-radiation performance. An n type first semiconductor substrate and p type second semiconductor substrate are directly bonded, and a buried oxide film is formed in a portion of a bonding interface thereof. Subsequently, a plurality of isolation trenches are formed and the first semiconductor substrate is separated into an SOI isolation region and a pn isolation region. Logic elements are then formed in the SOI isolation region, and power elements are formed in the pn isolation region. In the case wherein two or more logic elements are hereby formed, the logic elements are isolated by isolation trenches. In the case wherein two or more power elements are formed, a parasitic current extracting portion is formed between mutual power elements.Type: GrantFiled: November 8, 1994Date of Patent: June 11, 1996Assignee: Nippondenso Co., Ltd.Inventors: Hiroaki Himi, Harutsugu Fukumoto, Seiji Fujino
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Patent number: 5498891Abstract: An erasable-programmable read only memory (EPROM) allowing a miniaturization of an isolation region (a field insulating layer) without generating a parasitic transistor. The EPROM includes a semiconductor substrate, a field insulating layer defining a device formation region of the semiconductor substrate, a gate insulating layer and a floating gate formed on the field insulating layer and the field insulating layer. The EPROM further includes a trench insulating layer extending into the semiconductor substrate at the center portion of the field insulating layer so that one of the side walls of the trench insulating layer is self-aligned with the end face of the floating gate. A first interlaminar insulating layer covers the floating gate, and a control gate is located above the first interlaminar insulating layer. A second interlaminar insulating layer is formed over the control gate and a bit line is formed on the second interlaminar insulating layer.Type: GrantFiled: May 12, 1994Date of Patent: March 12, 1996Assignee: Fujitsu LimitedInventor: Noriaki Sato
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Patent number: 5479041Abstract: The invention describes a non-trenched buried contact for local interconnections in VLSI devices and provides a method for forming the non-trenched buried contact. By using trenched isolation and a trench polysilicon gate structure the buried contact process can be implemented so that there are no unwanted trenches formed in the area of the buried contact. The invention permits excellent planarization of the device prior to pre-metal dielectric and metal deposition.Type: GrantFiled: December 12, 1994Date of Patent: December 26, 1995Assignee: United Microelectronics CorporationInventors: Water Lur, D. Y. Wu
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Patent number: 5461248Abstract: A trench capacitor memory cell having a semiconductor substrate, an active region having a transistor on a portion of the semiconductor substrate, a field region formed by removing portion of the semiconductor substrate except for portions of the active region to a certain depth below the surface of the semiconductor substrate, a capacitor trench region formed in contact with a part of the active region and within the field region, and a polysilicon plug formed within the field region except for the trench region, and insulated by being surrounded by an insulating layer.Type: GrantFiled: March 3, 1994Date of Patent: October 24, 1995Assignee: Goldstar Electron Co., Ltd.Inventor: Young-Kwon Jun
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Patent number: 5436488Abstract: The reliability of integrated circuits fabricated with trench isolation is improved by increasing the thickness of the gate dielectric overlying the trench corner. After the trench isolation region (40, 56) has been formed a thin layer of silicon dioxide (44) is chemically vapor deposited over the trench isolation region (44) and the adjacent active region (23). A transistor gate electrode (46) is subsequently formed over the thin layer of silicon dioxide (44). The thin layer of silicon dioxide (44) increases the thickness of the gate dielectric that lies between the transistor gate electrode (46) and the trench corner, and therefore the breakdown voltage of the gate dielectric at the trench corner is increased.Type: GrantFiled: October 31, 1994Date of Patent: July 25, 1995Assignee: Motorola Inc.Inventors: Stephen S. Poon, Hsing-Huang Tseng
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Patent number: 5397908Abstract: A semiconductor processing device isolation method includes: a) providing non-LOCOS insulating device isolation blocks by trench and refill technique on a substrate to define recessed moat volume therebetween; b) providing gate dielectric within the moat volume; c) providing a layer of electrically conductive material over the substrate and gate dielectric to a thickness sufficient to completely fill the moat volume between adjacent isolation blocks; d) chemical-mechanical polishing the layer of electrically conductive material to provide a planarized upper electrically conductive material surface; e) photopatterning and etching the layer of electrically conductive material to provide an electrically conductive runner which overlies a plurality of the isolation blocks and to selectively remove the electrically conductive material from within selected regions of moat volume to define field effect transistor gates within the moat volume; and f) providing conductivity enhancing impurity through the selected regiType: GrantFiled: December 9, 1993Date of Patent: March 14, 1995Assignee: Micron Technology, Inc.Inventors: Charles H. Dennison, Trung T. Doan
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Patent number: 5381033Abstract: A dielectrics dividing wafer is disclosed in which embedded dielectric films are provided in the interior of the wafer in a predetermined pattern extending laterally parallel to a face surface of the wafer, and partition dielectric films, in the form of vertical walls extending from the face surface and the rear surface of the wafer, to the embedded dielectric films, are provided to define semiconductor areas extending continuously from the face surface of the wafer to the rear surface of the wafer. The semiconductor areas can be used for vertical circuit elements. The partition dielectric films in conjunction with the embedded dielectric films and the face surface of the wafer also define additional planar semiconductor areas that can be used for planar structure circuit elements.Type: GrantFiled: January 27, 1994Date of Patent: January 10, 1995Assignee: Fuji Electric Company, Ltd.Inventor: Kazuo Matsuzaki
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Patent number: 5373180Abstract: Through the use of a specifically configured buried dielectric region, devices with strict design rules, e.g., design rules of 0.9 micrometers and less, are significantly improved. In particular, the recessed dielectric region, e.g., field oxide, separating device areas in an integrated circuit, either has a buried conducting shield surrounding the periphery of the oxide or has a configuration such that the upper surface of the dielectric is no more than 20 nm below the upper surface of the silicon forming the device active region. By insuring a suitable configuration, parasitic capacitance resulting in slower operation is considerably reduced while leakage currents are maintained at an acceptable level.Type: GrantFiled: September 14, 1993Date of Patent: December 13, 1994Assignee: AT&T Corp.Inventors: Steven J. Hillenius, William T. Lynch, Lalita Manchanda, Mark R. Pinto, Sheila Vaidya
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Patent number: 5306940Abstract: In a semiconductor device having an element isolation region including a LOCOS type field oxide film formed in a surface of a silicon substrate and a U-trench isolation region provided in the silicon substrate, the U-trench isolation region is constituted with a U-trench provided such that it penetrates the field oxide film, a channel stopper provided in a portion of the silicon substrate exposed on a bottom face of the U-trench, a first film in a form of a silicon oxide film formed by thermal oxidation of an exposed portion of the silicon substrate in the U-trench, a second film comprising a buried layer having thermal reflow characteristics and burying the U-trench, a third film having non-thermal reflow characteristics and having a top face substantially coplanar with a top face of the field oxide film and a bottom face connected to a top face of the second films and a fourth film in a form of an insulating film connected to the top face of the third film at an upper end of said U-trench and covering the UType: GrantFiled: October 21, 1991Date of Patent: April 26, 1994Assignee: NEC CorporationInventor: Toru Yamazaki
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Patent number: 5278438Abstract: A nonvolatile storage device is provided with at least one stacked poly gate structure formed on the substrate and disposed between a first trench and a second trench. The trenches each having two walls. A first doped area having a first conductivity type extending along the wall of the first trench and a second doped area having a second conductivity type extending along the wall of the second trench. The first doped area and the second doped area having heights greater than widths, the heights being parallel to the trench walls and the widths being perpendicular thereto. The trench walls are lined with a metal silicide to decrease resistivity.Type: GrantFiled: December 19, 1991Date of Patent: January 11, 1994Assignee: North American Philips CorporationInventors: Manjin J. Kim, Jein-Chen Young
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Patent number: 5223731Abstract: Disclosed is a floating gate EPROM cell wherein a trench is formed in and divides the semiconductor substrate into two portions. Separated source and drain regions are formed in one portion and contact one side of the trench region, and a control gate region is formed in the second portion and contacts the opposite side of the trench. A first insulating film covers the source, drain, trench regions and part of the control gate region, a portion of which is covered by a first polycrystalline silicon film which forms the floating gate. A second insulating layer covers the first polycrystalline silicon film and also a portion of the control gate region, which, in turn, is covered by a second polycrystalline silicon layer which extends beyond the second insulating layer into electrical contact with the control gate region. Thus, a control gate is provided both above and below the floating gate.Type: GrantFiled: December 9, 1991Date of Patent: June 29, 1993Assignee: Goldstar Electron Co., Ltd.Inventor: Sangsoo Lee