Including Doping Of Trench Surfaces Patents (Class 438/389)
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Publication number: 20020102808Abstract: A method for forming a dielectric layer with uniform thickness in a trench capacitor comprises providing a substrate structure. A trench device formed in the substrate structure is used as a capacitor and has sidewall and a bottom. Next, the sidewall of the trench device are treated by ion bombardment for forming amorphous structure thereon. Then a dielectric layer, such as an oxide layer, is formed on the sidewall and the bottom of the trench device by CVD or thermal oxidation. To be specific, because of amorphous structure of the sidewall and bottom of the trench device, the dielectric layer can have uniform thickness profile in the trench device.Type: ApplicationFiled: January 31, 2001Publication date: August 1, 2002Inventors: Skyland Pu, Yi-Fan Chen
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Patent number: 6417064Abstract: A method of treating the surface of a deep trench is disclosed. After forming a deep trench in a silicon substrate, the silicon substrate near the surfaces of the deep trench is treated to become amorphous. An annealing process is executed to make the amorphous silicon layer recrystallize into its original lattice arrangement, so as to reduce lattice defects in the surface of the deep trench.Type: GrantFiled: May 2, 2001Date of Patent: July 9, 2002Assignee: Nanya Technology CorporationInventors: Shian-Jyh Lin, Hai-Han Hung
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Patent number: 6406970Abstract: A process for forming a buried strap for memory cells of a semiconductor device having reduced process complexity and improved thickness control of the top trench oxide (TTO) (26). A first oxide layer (16) is deposited over a substrate (11) having trenches formed therein. A first semiconductor material (18) is deposited within the trenches (14). A nitride layer (20) is formed over exposed semiconductor substrate (20) within trenches (14), and a second semiconductor layer (22) is deposited over the nitride layer (20). The top surfaces of the second semiconductor layer (22) are doped to form doped regions (24) and leave undoped second semiconductor layer (22) on the trench (14) sidewalls. The undoped second semiconductor layer (22) is removed from the trench (14) sidewalls, and the doped semiconductor layer (24) within the trench (14) is oxidized to form an oxide region (26), which forms a TTO, within the doped second semiconductor layer (24).Type: GrantFiled: August 31, 2001Date of Patent: June 18, 2002Assignee: Infineon Technologies North America Corp.Inventors: Stephan Kudelka, Helmut Horst Tews
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Patent number: 6399435Abstract: The present invention provides a method for fabricating a DRAM cell having a trench capacitor. In order to simplify the fabrication method for a DRAM cell, to ensure a high yield and to achieve a high packing density of the DRAM cells, the invention proposes that the storage capacitor (4) of the DRAM cell and the selection transistor (3) be fabricated independently of one another. This saves method steps which, in the prior art, have to be carried out in order to isolate capacitor (9) and gate (16) in the same trench.Type: GrantFiled: October 15, 2001Date of Patent: June 4, 2002Assignee: Infineon Technologies AGInventor: Jenoe Tihanyi
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Patent number: 6372573Abstract: A process for eliminating roughness on a silicon nitride trench liner is disclosed. A capping film on the top of the trench is formed in a self-aligned manner. This capping film prevents short circuits between a storage node and a passing word-line.Type: GrantFiled: October 26, 1999Date of Patent: April 16, 2002Assignee: Kabushiki Kaisha ToshibaInventors: Masami Aoki, Hirofumi Inoue, Bruce W. Porth, Max G. Levy, Victor R. Nastasi, Emily E. Fisch, Paul C. Buschner
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Patent number: 6362040Abstract: A method for growing a dielectric layer on a substrate, in accordance with the present invention, includes the steps of providing a substrate having at least two crystallographic planes which experience different dielectric layer growth rates due to the at least two crystallographic planes. A first dielectric layer is grown on the at least two crystallographic planes such that the first dielectric layer has a first thickness on a first crystallographic plane and a second thickness on a second crystallographic plane. The first thickness is thicker than the second thickness for the first dielectric layer. Dopants are implanted through the first dielectric layer. A greater number of dopants are implanted in the substrate through the second thickness than through the first thickness of the first dielectric layer. The first dielectric layer is then removed. A second dielectric layer is grown at a same location as the removed first dielectric layer.Type: GrantFiled: February 9, 2000Date of Patent: March 26, 2002Assignees: Infineon Technologies AG, International Business Machines CorporationInventors: Helmut Horst Tews, Brian S. Lee, Ulrike Gruening, Raj Jammy, John Faltermeier
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Publication number: 20020022316Abstract: The method according to the invention enables the roughness of an HSG surface to be substantially transferred to the surface of an electrode. The electrode consequently acquires a microstructured surface, the area of which can be increased by more than 25%, preferably by more than 50% and particularly preferably by more than 100%. An HSG layer is used to locally mask the electrode surface or the sacrificial layer. Subsequent structuring processes, such as for example wet-chemical and/or plasma-assisted etching processes, nitriding or oxidation processes, make it possible—working on the basis of micromasking effects—to significantly roughen the electrode surface and thereby to increase the electrode surface area.Type: ApplicationFiled: August 7, 2001Publication date: February 21, 2002Inventors: Martin Gutsche, Alexander Gschwandtner
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Patent number: 6297088Abstract: A method of forming a DRAM cell with a trench capacitor over a semiconductor substrate comprises the following steps. First, an etching step is performed to form a trench structure in the substrate, wherein the trench structure has a bottom and sidewalls, and the sidewalls are adjacent to the bottom. And each the sidewall includes an upper sidewall adjacent to the substrate through a insulating layer and a lower sidewall adjacent to the substrate through a dielectric layer. Then, after the etching steps, a doped area is formed on the bottom and the lower sidewall for serving as the first electrode of the trench capacitor. A first conducting layer is formed on the doped area and the insulating layer above a portion of the upper sidewall to serve as a first capacitor electrode.Type: GrantFiled: June 2, 2000Date of Patent: October 2, 2001Inventor: Wei-Shang King
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Publication number: 20010023956Abstract: A trench capacitor having an increased surface area. In one embodiment, the trench capacitor is a dual trench capacitor having a first trench and a second trench wherein inner walls of the trenches electrically connect. The invention also includes a single trench capacitor wherein the trench is curved around an axis substantially perpendicular to a substrate surface.Type: ApplicationFiled: January 23, 2001Publication date: September 27, 2001Inventors: Christopher N. Collins, Harris C. Jones, James P. Norum, Stefan Schmitz
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Patent number: 6284593Abstract: A process of forming a hybrid memory cell which is scalable to a minimum feature size, F, of about 60 nm at an operating voltage of Vblh of about 1.5 V and substantially free of floating-well effects is provided.Type: GrantFiled: November 3, 2000Date of Patent: September 4, 2001Assignee: International Business Machines CorporationInventors: Jack A. Mandelman, Ramachandra Divakaruni, Carl J. Radens
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Patent number: 6281068Abstract: An improved method of forming the buried plate regions in deep trench capacitors used in DRAM memory semiconductor circuits in which the polymer used in the deep trench is etched down to the desired depth in a reactive ion etch tool using an O2/CF4 chemistry. Since optical/interferometric etch end-point detection system can be used to monitor the etch back step in its totality, the quantity of the polymer remaining in deep trenches can be very accurately controlled, which in turn will produce a well controlled buried plate region during the out-diffusion step of the arsenic dopant contained in the arsenic doped silicon glass layer.Type: GrantFiled: April 14, 1999Date of Patent: August 28, 2001Assignee: International Business Machines CorporationInventors: Philippe Coronel, David Cruau, Francois Leverd, Renzo Maccagnan, Eric Mass
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Patent number: 6265279Abstract: A trench capacitor, in accordance with the present invention, includes a trench formed in a substrate. The trench has a buried plate formed adjacent to a lower portion of the trench. A dielectric collar is formed along vertical sidewalls of the trench. A node diffusion region is formed adjacent to the trench for connecting to a storage node in the trench. A dopant region is formed laterally outward from the trench and adjacent to the collar, and the dopant region includes a profile having a lower portion extending further laterally outward from the trench than an upper portion of the profile wherein operation of a parasitic transistor formed adjacent to the trench between the node diffusion and the buried plate is disrupted by the dopant region. Methods for forming the dopant region are also disclosed and claimed.Type: GrantFiled: September 24, 1999Date of Patent: July 24, 2001Assignees: Infineon Technologies AG, International Business Machines CorporationInventors: Carl Radens, Jack A. Mandelman, Joachim Hoepfner
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Patent number: 6265278Abstract: The preferred embodiment provides an integrated circuit capacitor that achieves a high capacitance by using an inversion layer in the substrate as the plate counter electrode for the capacitor. The inversion layer is created by forming a trench capacitor in a lightly doped substrate. With a sufficient workfunction difference between the storage node material and the isolation band the surface of the lightly doped substrate inverts, with the inversion charge being supplied by the isolation band. This inversion layer serves as the plate counter electrode for the capacitor.Type: GrantFiled: May 14, 1998Date of Patent: July 24, 2001Assignees: International Business Machines Corporation, Siemens AktiengesellschaftInventors: Johann Alsmeier, Jack Allan Mandelman, James Anthony O'Neill, Christopher Parks, Paul Christian Parries
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Patent number: 6261894Abstract: Methods of preparing dual workfunction high-performance support metal oxide semiconductor field effect transistor (MOSFETs)/embedded dynamic random access (EDRAM) arrays are provided. The methods describe herein reduce the number of deep-UV masks used in the forming memory structure, decouple the support and arraying processing steps, provide salicided gates, source/drain regions and bitlines, and provide, in some instances, local interconnects at no additional processing costs. Dual workfunction high-performance support MOSFETs/ EDRAM arrays having a gate conductor guard ring and/or local interconnections are also provided.Type: GrantFiled: November 3, 2000Date of Patent: July 17, 2001Assignee: International Business Machines CorporationInventors: Jack A. Mandelman, Ramachandra Divakaruni, Carl J. Radens
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Patent number: 6251722Abstract: A method of fabricating a trench capacitor having high capacitance for ULSI technology below the sub-micrometer scale is provided. The method includes: form a trench on a semiconductor substrate. The trench has a bottom portion and at least one sidewall on the semiconductor substrate. Then, form a diffusion layer in the silicon substrate for circumscribing the bottom portion of the trench and a predetermined region of its sidewall. After that, form a first polysilicon layer on the bottom portion of the trench and in a manner that a portion of the first polysilicon layer does not contact with the sidewall. Then, form a first dielectric layer to completely cover the first polysilicon layer and the diffusion layer. Then, form an upper electrode layer on top of the trench to at least completely cover the first dielectric layer. Eventually, the contact area between the diffusion layer and the dielectric layer has been largely increased so as to maintain sufficient capacitance.Type: GrantFiled: April 11, 2000Date of Patent: June 26, 2001Assignee: Mosel Vitelic Inc.Inventors: Houng-chi Wei, Tso-chun Tony Wang
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Patent number: 6245612Abstract: The present invention provides a method for making the bottom electrode of a buried capacitor, which is characterized by protecting the non-bottom electrode region with a LPD oxide layer to prevent the impurities within the doped Si glass remaining in non-bottom electrode region from driving into the substrate during annealing, thus non-desired diffusing region connecting to the bottom electrode will be generated. Consequently, the leakage current existing in conventional buried capacitor will be effectively reduced according to the method of this present invention.Type: GrantFiled: March 22, 2000Date of Patent: June 12, 2001Assignee: Winbond Electronics Corp.Inventors: Wen-Pin Chang, Ming-Lun Chang
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Patent number: 6232171Abstract: A method for fabricating deep-submicron vertically arranged capacitors is disclosed which allows the capacitor to enjoy an enhanced sidewall surface so as to attain a capacitance of 40 pF or more.Type: GrantFiled: June 8, 1999Date of Patent: May 15, 2001Assignees: ProMOS Technology, Inc., Mosel Vitelic Inc., Siemens AGInventor: Len Mei
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Patent number: 6211006Abstract: The present invention relates to a method of forming a trench-type capacitor. More particularly, the plate areas of the trench-type capacitor are increased according to the present invention.Type: GrantFiled: November 5, 1999Date of Patent: April 3, 2001Assignee: Nanya Technology CorporationInventors: Hsin-Chuan Tsai, Yi-Nan Chen, Pei-Ing Paul Lee
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Patent number: 6207494Abstract: A method of fabricating a trench cell capacitor can be used in the formation of a DRAM cell. In one embodiment, a trench is formed within a semiconductor substrate. The trench is lined with a dielectric layer, e.g., an ONO layer. After lining the trench, a collar is formed in an upper portion of the trench by forming an oxide layer in the upper portion. A nitride layer on the oxide layer. The trench is then filled with semiconductor material. For example, a semiconductor region can be epitaxially grown to fill the trench.Type: GrantFiled: March 31, 1999Date of Patent: March 27, 2001Assignee: Infineon Technologies CorporationInventors: Christoff Graimann, Angelika Schulz, Carlos A. Mazure, Christian Dieseldorff
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Patent number: 6204128Abstract: A method for fabricating a semiconductor device includes the steps of: forming a doped layer of a first conductivity type within a surface region of a semiconductor substrate; forming a recess by depositing an insulating film on the semiconductor substrate and then removing at least the insulating film in a region thereof where a gate electrode is to be formed; forming a gate insulating film on the surface of the semiconductor substrate, which is exposed inside the recess; and forming the gate electrode by filling in the recess with a conductive film.Type: GrantFiled: August 26, 1999Date of Patent: March 20, 2001Assignee: Matsushita Electronics CorporationInventors: Toshitaka Hibi, Kazuo Hayama
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Patent number: 6190971Abstract: A method and structure for manufacturing an integrated circuit device includes forming a storage device in a substrate, lithographically forming a gate opening in the substrate over the storage device, forming first spacers in the gate opening, forming a strap opening in the substrate using the first spacers to align the strap opening, forming second spacers in the strap opening, forming an isolation opening in the substrate using the second spacers to align the isolation opening, filling the isolation opening with an isolation material, removing the first spacers and a portion of the second spacers to form a step in the gate opening, (wherein the second spacers comprise at least one conductive strap electrically connected to the storage device) forming a first diffusion region in the substrate adjacent the conductive strap, forming a gate insulator layer over the substrate and the step, forming a gate conductor over a portion of the gate insulator layer above the step, forming a second diffusion region in thType: GrantFiled: May 13, 1999Date of Patent: February 20, 2001Assignees: International Business Machines Corporation, Infineon Technologies North America Corp.Inventors: Ulrike Gruening, Carl J. Radens
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Patent number: 6190988Abstract: A bottle-shaped trench capacitor with a buried plate is formed in a controlled etch process. The bottle-shape is fabricated by etching deep trenches from a layered substrate, using the layers as a mask, and covering the side walls of the substrate with protective oxide and nitride layers. With the side walls covered, deep trench etching is then resumed, and a lower trench portion, below the protective layers of the side wall are formed. By diffusing a first dopant in the lower portion of the deep trench region, using the side wall protective layers as a mask, an etch stop is established for a wet etch process at the p/n junction established by the first dopant. The width of the lower trench portion is regulated by the time and temperature of the diffusion. Removing the doped material and applying a second dopant to the lower trench portion establishes a continuous buried plate region between trenches. A capacitor is formed by applying an insulating layer to the trench and filling with a conductor.Type: GrantFiled: May 28, 1998Date of Patent: February 20, 2001Assignee: International Business Machines CorporationInventors: Toshiharu Furukawa, Mark C. Hakey, Steven J. Holmes, David Horak, William H. Ma, James M. Never
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Patent number: 6159874Abstract: A method of manufacturing a capacitor is provided where at least a portion of a silicon surface is amorphized. The amorphized silicon surface is then subjected to an annealing process to form hemispherical silicon grains (HSG) from the amorphized portion of the silicon surface to form at least a portion of a first electrode of the capacitor. A capacitor dielectric is then formed over the hemispherical silicon grains. A second electrode is then formed over the capacitor dielectric.Type: GrantFiled: October 27, 1999Date of Patent: December 12, 2000Assignee: Infineon Technologies North America Corp.Inventors: Helmut Horst Tews, Brian Lee
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Patent number: 6143616Abstract: Methods of forming integrated circuitry lines such as coaxial integrated circuitry interconnect lines, and related integrated circuitry are described. An inner conductive coaxial line component is formed which extends through a substrate. An outer conductive coaxial line component and coaxial dielectric material are formed, with the coaxial dielectric material being formed operably proximate and between the inner and outer conductive coaxial line components. In a preferred implementation, the substrate includes front and back surfaces, and a hole is formed which extends through the substrate and between the front and back surfaces. In one implementation, the outer conductive coaxial line component constitutes doped semiconductive material. In another implementation, such constitutes a layer of metal-comprising material. A layer of dielectric material is formed over and radially inwardly of the outer line component. Conductive material is then formed over and radially inwardly of the dielectric material layer.Type: GrantFiled: August 22, 1997Date of Patent: November 7, 2000Assignee: Micron Technology, Inc.Inventors: Joseph E. Geusic, Kie Y. Ahn, Leonard Forbes
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Patent number: 6107153Abstract: A method for forming a trench capacitor of a dynamic random access memory cell is disclosed. The method includes patterning to etch a semiconductor substrate (10) of a first conductivity to form a trench (18) in the substrate. Ions of the first conductivity are tilt-implanted over the trench, so that sidewalls and a bottom surface of the substrate near the trench are doped with the ions of the first conductivity. Next, first ions of a second conductivity are tilt-implanted over the trench at a first angle, thereby forming a first implanted region (22), followed by tilt-implanting second ions of the second conductivity over the trench at a second angle, thereby forming a second implanted region (24). The first angle is larger than the second angle, and the first implanted region and the second implanted region together form a bottom cell plate of the trench capacitor.Type: GrantFiled: January 26, 1998Date of Patent: August 22, 2000Assignee: Texas Instruments -Acer IncorporatedInventors: Li-Ping Huang, Shye-Lin Wu
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Patent number: 6100132Abstract: A semiconductor device includes a semiconductor substrate having a trench on a surface thereof and an embedding member embedding the interior of the trench therewith. While the section of the trench when cut by a first plane perpendicular to the direction of the depth of the trench is defined as a first section and the section of the trench when cut by a second plane perpendicular to the direction of the depth of the trench and closer to the bottom of the trench than the first plane is defined as a second section, the area of the first section is smaller than that of the second section and a minimum radius of curvature of the first section is smaller than a minimum radius of curvature of the second section. As a result, it is possible to lessen the concentration of the electric field into the bottom of the trench.Type: GrantFiled: June 29, 1998Date of Patent: August 8, 2000Assignee: Kabushiki Kaisha ToshibaInventors: Tsutomu Sato, Ichiro Mizushima, Yoshitaka Tsunashima, Junichiro Iba
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Patent number: 6093614Abstract: A pair of memory cells for use in a DRAM are formed in a monocrystalline bulk portion of a silicon wafer by first forming a pair of vertical trenches spaced apart by a bulk portion of the wafer. After a dielectric layer is formed over the walls of each trench, the trenches are each filled with polycrystalline silicon. By a pair of recess forming and recess filling steps there is formed at the top of each trench a silicon region that was grown epitaxially with the intermediate bulk portion. Each epitaxial region is made to serve as the body of a separate transistor having its drain in the lower polysilicon fill of a trench, and its source in the monocrystalline bulk intermediate between the two epitaxial regions. The lower polysilicon fill of each trench is also made to serve as the storage node of the capacitor of each cell, with the bulk serving as the other plate of the capacitor.Type: GrantFiled: March 4, 1998Date of Patent: July 25, 2000Assignee: Siemens AktiengesellschaftInventors: Ulrike Gruening, Jochen Beintner, Hans-Oliver Joachim
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Patent number: 6080618Abstract: Reduced variations in buried layer across the chip is provided. The reduction in variation is achieved by defining the top surface of the buried layer and then the lower surface of the buried layer. This results in improved control buried strap variations, thereby improving performance of the IC.Type: GrantFiled: March 31, 1998Date of Patent: June 27, 2000Assignee: Siemens AktiengesellschaftInventors: Wolfgang Bergner, Johann Alsmeier
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Patent number: 6077740Abstract: A structure and process for forming a contact to a semiconductor substrate on a semiconductor device comprises the step of forming a patterned mask over a semiconductor substrate and over a field oxide region, then etching the semiconductor substrate and the field oxide region to form a trench. The trench comprises a bottom and a first sidewall consisting of silicon and a second sidewall comprising field oxide. The etching step removes a part of a doped region in the substrate. Next, a blanket nitride layer and a blanket oxide layer is formed over the substrate, and a spacer etch is performed on the nitride and oxide layer leaving nitride and oxide over the first and second sidewalls. The trench bottom is oxidized to form a layer of oxide over the bottom of the trench thereby insulating the trench bottom, and the oxide encroaches under the nitride and oxide on the sidewalls to join with the field oxide.Type: GrantFiled: February 17, 1998Date of Patent: June 20, 2000Assignee: Micron Technology, Inc.Inventors: Nanseng Jeng, Steven T. Harshfield, Paul J. Schuele
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Patent number: 6064085Abstract: The present invention discloses a novel multiple fin-shaped capacitor for use in semiconductor memories. The capacitor has a plurality of horizontal fins and a crown shape. The capacitor structure comprises a bottom storage electrode. The bottom storage electrode comprises of a plurality of horizontal fins and a crown shape, wherein said crown shape includes two vertical pillars, and said plurality of horizontal fins extend outside from an external surface of said crown shape. A second dielectric layer is formed on the surface of the bottom storage electrode layer. A top storage electrode layer is formed along the surface of second dielectric layer. By including horizontal fins and vertical pillars, the surface area of the capacitor is significantly increased, resulting in increased capacitance.Type: GrantFiled: June 3, 1998Date of Patent: May 16, 2000Assignee: Texas Instruments-Acer IncorporatedInventor: Shye-Lin Wu
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Patent number: 6057188Abstract: An optimized trench capacitor structure which is useful as a decoupling capacitor or a storage capacitor can be manufactured without added process complexity. As an on-chip decoupling trench capacitor structure, the structure reduces the series resistance to outer and inner plates and results in an acceptable RC delay, while maintaining a high capacitance per unit area. As a storage capacitor with a buried shield, the trench capacitor structure exhibits high immunity to alpha particle and cosmic radiation induced failures. The trench capacitor structure which includes a buried n-well in a silicon substrate. A trench is formed in the substrate and extends through the buried n-well. A dielectric film is formed on an inner surface of the trench, and an inner plate formed as a polysilicon fill within the trench is connected to a surface n+ film formed during definition of peripheral source/drain contacts of the integrated circuit.Type: GrantFiled: February 5, 1998Date of Patent: May 2, 2000Assignee: International Business Machines CorporationInventors: Badih El-Kareh, Richard Leo Kleinhenz, Stanley Everett Schuster
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Patent number: 6008103Abstract: A method for forming a trench capacitor in a substrate, including a buried plate of the trench capacitor, is disclosed. The method includes forming a trench within the substrate. The trench has a trench interior surface. The method further includes forming an oxide collar within the trench. The oxide collar covers a first portion of the trench interior surface, leaving a second portion of the trench interior surface uncovered with the oxide collar. There is also included doping the second portion of the trench interior surface with a first dopant using a plasma-enhanced doping process. The plasma-enhanced doping process being configured to cause the first dopant to diffuse into the second portion substantially without depositing an additional layer on the trench interior surface. Additionally, there is included driving the first dopant into the substrate using a high temperature process to form the buried plate.Type: GrantFiled: February 27, 1998Date of Patent: December 28, 1999Assignee: Siemens AktiengesellschaftInventor: Joachim Hoepfner
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Patent number: 6004844Abstract: A DRAM unit cell is disclosed which comprises a trench capacitor having a signal electrode, a bit line, a planar active word line overlapping the trench capacitor and a planar FET having a main conducting path coupled between the signal electrode of the trench capacitor and the bit line and a gate electrode formed by the active word line.Type: GrantFiled: July 15, 1996Date of Patent: December 21, 1999Assignee: Siemens AktiengesellschaftInventors: Johann Alsmeier, Martin Gall
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Patent number: 5998254Abstract: The method sequence results in a conductive connection between two zones of a first conductivity type. In particular, one of the zones is a source/drain zone of a transistor. Instead of the conventional additional nitride layer, the connection is produced by implanting directly into the third insulation layer, which is present anyway, and by utilizing the fact that the third insulation layer forms the lateral spacers on the gatestack disposed on the region of the second conductivity type.Type: GrantFiled: April 6, 1998Date of Patent: December 7, 1999Assignee: Siemens AktiengesellschaftInventor: Lars-Peter Heineck
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Patent number: 5985729Abstract: A silicon oxide layer is formed on the wafer to act as a pad layer. A silicon nitride layer is then formed on the silicon oxide layer to have a thickness approximate 1500-2000 angstroms. At least one trench is then created in the wafer. Then, an ion implantation process is performed with at least one titled angle to dope ions into the surface of the trenches. A LPD-oxide is selectively deposited in the trench. Then, a polysilicon layer is formed on the LPD-oxide and on the surface of the silicon nitride layer. Next, the polysilicon layer is etched to generate polysilicon side-wall spacers. The LPD-oxide is etched using the polysilicon side-wall spacers and the silicon nitride layer as an etching mask. The polysilicon side-wall spacers are then removed. A first conductive layer is formed on the silicon nitride layer, and refilled into the first trenches. The first conductive layer is then etched to at least to expose the LPD-oxide. The LPD-oxide is removed.Type: GrantFiled: April 2, 1998Date of Patent: November 16, 1999Assignee: Texas Instruments - Acer IncorporatedInventor: Shye-Lin Wu
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Patent number: 5953607Abstract: A dynamic random access memory (DRAM) cell is formed with a buried strap which is routed through an isolation trench. This structure frees space in the transfer gate such that the location of the buried strap is not a limiting factor for decreasing the size of DRAM cells.Type: GrantFiled: June 6, 1997Date of Patent: September 14, 1999Assignee: International Business Machines CorporationInventors: Mark C. Hakey, David V. Horak, Jack A. Mandelman, Wendell P. Noble
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Patent number: 5942778Abstract: A semiconductor device includes (a) a first conductivity type semiconductor substrate having a plurality of trenches formed therein, the trenches defining a plurality of device regions between adjacent trenches, (b) a second conductivity type diffusion layer formed at least around an outer surface of each of the device regions, (c) an insulating film formed on the inner surface of each of the trenches to cover a part of the second conductivity type diffusion layer therewith, (d) a plate electrode formed within each of the trenches, (e) a gate electrode formed above the second conductivity type diffusion layer and (f) a gate insulating film interposed between the gate electrode and the second conductivity type diffusion layer to isolate the gate electrode from the second conductivity type diffusion layer. This semiconductor device eliminates the need for the second conductivity type diffusion layer to serve as a capacitor electrode in contact with a switching transistor.Type: GrantFiled: September 12, 1997Date of Patent: August 24, 1999Assignee: NEC CorporationInventor: Ryuichi Oikawa
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Patent number: 5923971Abstract: Strap resistance, surface strap shorts and wordline capacitance can be reduced by providing a selectively grown silicon strap which tapers away from spacer nitride and has less contact with spacer nitride. In addition the strap is optionally doped with an arsenic implant which reduces resistance.Type: GrantFiled: October 22, 1996Date of Patent: July 13, 1999Assignee: International Business Machines CorporationInventors: Herbert L. Ho, Andre R. LeBlanc, Jack A. Mandelman, Radhika Srinivasan
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Patent number: 5885863Abstract: A method for forming a contact is disclosed. A buried impurity region of a second conductivity type is formed in a semiconductor substrate of a first conductivity type. First and second well regions of a first and second conductivity types, respectively, are also formed in the semiconductor substrate. The second well region overlaps the first well region and contacts and surrounds the buried impurity region. A surface impurity concentration of the first well region is greater than a surface impurity concentration of the second well region. A contact to the second well region is formed.Type: GrantFiled: March 31, 1997Date of Patent: March 23, 1999Assignee: Kabushiki Kaisha ToshibaInventor: Seiko Yoshida
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Patent number: 5753558Abstract: A method of forming a capacitor includes, a) providing a substrate; b) etching into the substrate to provide a depression in the substrate, the depression having a sidewall which is angled from vertical; c) providing a conformal layer of hemispherical grain polysilicon within the depression and over the angled sidewall, the layer of hemispherical grain polysilicon less than completely filling the depression; and d) ion implanting the hemispherical grain polysilicon layer with a conductivity enhancing impurity. Preferred methods of providing the depression where the substrate comprises SiO.sub.2 include a dry, plasma enhanced, anisotropic spacer etch utilizing reactant gases of CF.sub.4 and CHF.sub.3 provided to the substrate at a volumetric ratio of 1:1, and facet sputter etching.Type: GrantFiled: April 18, 1997Date of Patent: May 19, 1998Assignee: Micron Technology, Inc.Inventors: Salman Akram, Charles Turner, Alan Laulusa
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Patent number: 5629226Abstract: A trench of a buried plate type DRAM has a bottom portion wider than an opening portion. A silicon oxide film is formed on an upper portion of the side wall of the trench. An N-type impurity diffusion region is formed around the bottom portion of the trench. Impurity diffusion regions of adjacent trenches are integrally connected with each other as one portion. A first polycrystalline silicon layer is formed on the impurity diffusion region in the trench and the silicon oxide film. The polycrystalline silicon layer is coated with a laminated film consisting of a silicon nitride film and a silicon oxide film. The trench is filled with a second polycrystalline silicon layer covering the laminated film. The impurity diffusion region serves as a plate diffusion region of a capacitor, the first polycrystalline silicon layer serves as a plate electrode, the laminated film serves as a capacitor insulating film, and the second polycrystalline silicon layer serves as a storage node electrode.Type: GrantFiled: July 24, 1995Date of Patent: May 13, 1997Assignee: Kabushiki Kaisha ToshibaInventor: Sumito Ohtsuki
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Patent number: 5270112Abstract: The subject invention relates to a hybrid reinforcement material comprising a refractory metal core having a first coating comprising aluminum, oxygen and nitrogen, this coating of the general formula:Al.sub.x O.sub.y N.sub.zwhereinx is up to about 670 atomic % of the coatingy is from about 20 atomic % to about 55 atomic % ofthe coating; andz is from about 5 atomic % to about 45 atomic % of the coating, with the proviso that x+y+z=100, and having a second SiC coating.The subject invention further relates to a high strength, high temperature performance composite containing the hybrid reinforcement specified above.Type: GrantFiled: December 20, 1989Date of Patent: December 14, 1993Assignee: Standard Oil CompanyInventors: D. Lukco, M. A. Tenhover