Patents by Inventor Lothar Risch

Lothar Risch has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 6038164
    Abstract: The SRAM cell configuration has at least six transistors in each memory cell. Four of the transistors form a flip-flop and they are arranged at the corners of a quadrilateral. The flip-flop is driven by two of the transistors, which are disposed so as to adjoin diagonally opposite corners of the quadrilateral and outside the quadrilateral. Adjacent memory cells along a word line can be arranged in such a way that a first bit line and a second bit line of the adjacent memory cells coincide. The transistors are preferably vertical and are arranged at semiconductor structures (St1, St2, St3, St4, St5, St6) produced from a layer sequence. Two of the transistors having n-doped channel regions are preferably formed in each case on two semiconductor structures.
    Type: Grant
    Filed: November 25, 1998
    Date of Patent: March 14, 2000
    Assignee: Siemens Aktiengesellschaft
    Inventors: Thomas Schulz, Thomas Aeugle, Wolfgang Rosner, Lothar Risch
  • Patent number: 6037209
    Abstract: The DRAM cell arrangement comprises, per memory cell, a vertical MOS transistor whose first source/drain region is connected to a storage node of a storage capacitor, whose channel region (3) is annularly enclosed by a gate electrode (13) and whose second source/drain region is connected to a buried bit line. The DRAM cell arrangement is produced using only two masks, with the aid of a spacer technique, with a memory cell area of 2F.sup.2, where F is the minimum structure size which can be produced using the respective technology.
    Type: Grant
    Filed: March 15, 1999
    Date of Patent: March 14, 2000
    Assignee: Siemens Aktiengesellschaft
    Inventors: Wolfgang Rosner, Lothar Risch, Franz Hofmann, Reinhard Stengl
  • Patent number: 5998261
    Abstract: An electrically writable and erasable read-only memory cell arrangement fabricated in a semiconductor substrate, preferably of monocrystalline silicon, or in a silicon layer of an SOI substrate. A cell array with memory cells is provided on a main surface of the semiconductor substrate. Each memory cell comprises an MOS transistor, vertical to the main surface and comprising, in addition to the source/drain region and a channel region arranged in-between, a first dielectric, a floating gate, a second dielectric and a control gate. A plurality of essentially parallel strip-shaped trenches are provided in the cell array. The vertical MOS transistors are arranged on the flanks of the trenches. The memory cells are in each case arranged on opposite flanks of the trenches.
    Type: Grant
    Filed: December 8, 1997
    Date of Patent: December 7, 1999
    Assignee: Siemens Aktiengesellschaft
    Inventors: Franz Hofmann, Wolfgang Rosner, Wolfgang Krautschneider, Lothar Risch
  • Patent number: 5973373
    Abstract: A read-only-memory cell arrangement comprises memory cells, each having a vertical MOS transistor, in a substrate (21) made of semiconductor material, the various logic values (zero, one) being implemented by gate dielectrics (27, 28) of different thickness. The memory cell arrangement can preferably be produced in a silicon substrate, with a small number of process steps and a high packing density. The memory cell arrangement and a drive circuit for read-out can in this case be produced in an integrated manner.
    Type: Grant
    Filed: March 26, 1997
    Date of Patent: October 26, 1999
    Assignee: Siemens Aktiengesellschaft
    Inventors: Wolfgang Krautschneider, Lothar Risch, Franz Hofmann, Wolfgang Rosner
  • Patent number: 5959328
    Abstract: An electrically programmable memory cell arrangement has a plurality of individual memory cells that respectively has an MOS transistor with a gate dielectric with traps, and which are arranged in rows that run in parallel. Adjacent rows thereby respectively run in alternating fashion on the bottom of the longitudinal trenches (5) and between adjacent longitudinal trenches (5) and are insulated against one another. The memory cell arrangement can be manufactured by means of self-adjusting process steps with a surface requirement per memory cell of 2 F.sup.2 (F: minimum structural size).
    Type: Grant
    Filed: January 7, 1997
    Date of Patent: September 28, 1999
    Assignee: Siemens Aktiengesellschaft
    Inventors: Wolfgang Krautschneider, Lothar Risch, Franz Hofmann, Hans Reisinger
  • Patent number: 5920099
    Abstract: A read-only memory cell array has a plurality of individual memory cells which each have a MOS transistor and which are arranged in rows running in parallel. In this context, adjacent rows run alternately at the bottom of the longitudinal trenches (6) and between adjacent longitudinal trenches (6) respectively and are insulated with respect to one another. The read-only memory cell array can be manufactured by self-aligning process steps with an area of 2 F.sup.2 (F: minimum structure size) being required per memory cell.
    Type: Grant
    Filed: September 11, 1997
    Date of Patent: July 6, 1999
    Assignee: Siemens Aktiengesellschaft
    Inventors: Wolfgang Krautschneider, Lothar Risch, Franz Hofmann
  • Patent number: 5920778
    Abstract: In a read-only memory cell arrangement having first memory cells which contain a vertical MOS transistor, and having second memory cells which do not contain vertical MOS transistors, the memory cells are arranged along opposite flanks of strip-shaped parallel insulation trenches (16). The width of the insulation trenches (16) is preferably equal to their separation, so that the memory cell arrangement can be produced with a space requirement of 2F.sup.2 per memory cell, F being the minimum structure size in the respective technology.
    Type: Grant
    Filed: September 23, 1997
    Date of Patent: July 6, 1999
    Assignee: Siemens Aktiengesellschaft
    Inventors: Wolfgang Rosner, Wolfgang Krautschneider, Franz Hofmann, Lothar Risch
  • Patent number: 5844834
    Abstract: Each memory cell of an array has a single-electron transistor and a single-electron memory element. The single-electron transistor is driven by a charge stored in the memory element. When a read voltage is applied, a current flows through the single-electron transistor which is dependent on the stored charge, but the stored charge in not changed. When a write voltage is applied, the magnitude of which is greater than the read voltage, then the stored charge is changed. The memory cells of the array are each connected between first lines and transverse second lines of a memory cell configuration.
    Type: Grant
    Filed: June 2, 1997
    Date of Patent: December 1, 1998
    Assignee: Siemens Aktiengesellschaft
    Inventors: Lothar Risch, Wolfgang Rosner
  • Patent number: 5828076
    Abstract: In its gate region (10), a silicon MOS technology component has a surface structure (6) having edges and/or vertices at which inversion regions, suitable as quantum wires or quantum dots, are preferentially formed when a gate voltage is applied. The surface structure is preferably formed as a silicon pyramid (6) by local molecular beam epitaxy.
    Type: Grant
    Filed: October 17, 1996
    Date of Patent: October 27, 1998
    Assignee: Siemens Aktiengesellschaft
    Inventors: Harald Gossner, Ignaz Eisele, Lothar Risch, Erwin Hammerl
  • Patent number: 5817552
    Abstract: For each storage cell, the DRAM cell arrangement has a vertical MOS transistor, the first source/drain region of which is connected to a memory node of a storage capacitor, the channel region of which is annularly enclosed by a gate electrode and the second source/drain region of which is connected to a buried bit line. The DRAM cell arrangement can be produced with a storage-cell area of 4F.sup.2 by using only two masks, F being the minimum producible structure size in the respective technology.
    Type: Grant
    Filed: April 22, 1996
    Date of Patent: October 6, 1998
    Assignee: Siemens Aktiengesellschaft
    Inventors: Wolfgang Roesner, Lothar Risch, Franz Hofman, Wolfgang Krautschneider
  • Patent number: 5744393
    Abstract: A method for production of a read-only-memory cell arrangement having vertical MOS transistors is provided. In order to produce a read-only-memory cell arrangement which has first memory cells having a vertical MOS transistor and second memory cells which do not have a vertical MOS transistor, holes provided with a gate dielectric and a gate electrode are etched in a silicon substrate with a layer sequencing corresponding to a source, a channel and a drain for the first memory cells. Insulation trenches whose separation is preferably equal to their width are produced for insulation of adjacent memory cells.
    Type: Grant
    Filed: April 17, 1997
    Date of Patent: April 28, 1998
    Assignee: Siemens Aktiengesellschaft
    Inventors: Lothar Risch, Franz Hofmann, Wolfgang Rosner, Wolfgang Krautschneider
  • Patent number: 5736761
    Abstract: The DRAM cell arrangement has one vertical MOS transistor per memory cell, whose first source/drain region adjoins a trenched bitline (5), whose gate electrode (13) is connected with a trenched wordline and whose second source/drain region (3) adjoins a substrate main surface (1). A capacitor dielectric (16), which is in particular a ferroelectric or paraelectric layer, is arranged on at least the second source/drain region and a capacitor plate (17) is arranged on the dielectric, so that the second source/drain region (3) acts additionally as a memory node. The DRAM cell arrangement can be manufactured with a memory cell surface of 4 F.sup.2.
    Type: Grant
    Filed: May 14, 1996
    Date of Patent: April 7, 1998
    Assignee: Siemens Aktiengesellschaft
    Inventors: Lothar Risch, Franz Hofmann, Wolfgang Roesner, Wolfgang Krautschneider
  • Patent number: 5710072
    Abstract: To produce an arrangement containing self-amplifying dynamic MOS transistor memory cells which each comprise a selection transistor, a memory transistor and a diode structure, the selection transistor and the memory transistor being connected in series via a common nodal point and the diode structure being connected between the common nodal point and the gate electrode (10) of the memory transistor, the selection transistor and the memory transistor are formed as vertical MOS transistors. For this purpose a vertical sequence of suitably doped zones (2, 3, 4) in which trenches (5, 6) are produced and which are provided with gate dielectric (7, 8) and gate electrode (9, 10) is produced, in particular, by LPCVD epitaxy or by molecular-beam epitaxy.
    Type: Grant
    Filed: November 18, 1996
    Date of Patent: January 20, 1998
    Assignee: Siemens Aktiengesellschaft
    Inventors: Wolfgang Krautschneider, Lothar Risch, Franz Hofmann
  • Patent number: 5559353
    Abstract: A first MOS transistor and a second MOS transistor are connected in series with a first complementary MOS transistor and a second complementary MOS transistor that are connected in parallel with one another. The transistors are each realized as a vertical layer sequence that forms the source, channel and drain and that which has a sidewall at which a gate dielectric and a gate electrode are arranged. The complementary MOS transistors connected in parallel with one another are realized in a common layer sequence of the source, channel and drain. The layer sequences that form the series-connected transistors are arranged above one another. The circuit structure is manufactured by epitaxal definition of the layer sequences, such as by molecular beam epitaxy.
    Type: Grant
    Filed: November 1, 1994
    Date of Patent: September 24, 1996
    Assignee: Siemens Aktiengesellschaft
    Inventors: Lothar Risch, Thomas Vogelsang, Franz Hofmann, Karl Hofmann
  • Patent number: 5516404
    Abstract: A method for manufacturing an electrically conductive tip for field emission cathodes of vacuum electronic components includes forming the tip of doped silicon by molecular beam epitaxy of doped silicon through an opening of a mask and onto a substrate of monocrystalline silicon. The molecular beam epitaxy also produces a doped silicon layer on the surface of the mask.
    Type: Grant
    Filed: July 15, 1994
    Date of Patent: May 14, 1996
    Assignee: Siemens Aktiengesellschaft
    Inventors: Ignaz Eisele, Harald Gossner, Hermann Baumgaertner, Lothar Risch
  • Patent number: 5443992
    Abstract: An insulating layer is grown on a principal face of a substrate that comprises a source terminal region. A first opening wherein the surface of the source terminal region is partially uncovered is provided in the insulating layer. A vertical layer sequence that comprises at least a channel region and a drain region for the MOS transistor is produced in the first opening by epitaxial growth of semiconductor material within situ doping. A second opening that is at least of a depth corresponding to the sum of the thicknesses of drain region and channel region is produced in the layer structure, a gate dielectric is applied on the surface thereof and a gate-electrode is applied on said gate dielectric.
    Type: Grant
    Filed: November 1, 1994
    Date of Patent: August 22, 1995
    Assignee: Siemens Aktiengesellschaft
    Inventors: Lothar Risch, Thomas Vogelsang, Franz Hofmann, Karl Hofmann
  • Patent number: 5432115
    Abstract: To make a contact between a capacitor electrode (13) disposed in a trench (11) and an MOS transistor source/drain region disposed outside the trench, a shallow etching is carried out in a self-aligned manner with respect to a field-oxide region insulating the MOS transistor by producing the trench (11) in a substrate (1). After forming an Si.sub.3 N.sub.4 spacer (10) at the edge (8), laid bare during the etching, of the substrate (1) the part laid bare of the field-oxide region (2) is first removed with the aid of a mask and the trench (11) is completed in a further etching. The contact is produced after the formation of an SiO.sub.2 layer (12) at the surface of the trench (11) after removing the Si.sub.3 N.sub.4 spacer (10) and producing the capacitor electrode (13) at the edge (8), laid bare by removing the Si.sub.3 N.sub.4 spacer (10), of the substrate (1).
    Type: Grant
    Filed: August 4, 1994
    Date of Patent: July 11, 1995
    Assignee: Siemens Aktiengesellschaft
    Inventors: Wolfgang Rosner, Franz Hofmann, Lothar Risch
  • Patent number: 5327374
    Abstract: An arrangement with self-amplifying dynamic MOS transistor storage cells has in each case a MOS selection transistor AT, whose gate is connected to a word line WL, and an MOS storage transistor ST at whose gate a capacitor C for charge storage acts. This self-amplifying storage cell can be written on and read out with only one bit line BL and one word line WL. The two transistors AT and ST are connected in series and a common drain source region DS is connected via a voltage-dependent resistor VR to the gate electrode GST of the control transistor. The advantages reside in the fact that the cell geometry can be scaled without at the same time the quantity Q of charge which can be read out on the bit line BL having to be reduced, in that the quantity Q of charge which can be read out is larger than a charge stored in the capacitor C which acts at the gate of the storage transistor ST and in that the two MOS transistors AT and ST can be produced relatively simply.
    Type: Grant
    Filed: December 29, 1992
    Date of Patent: July 5, 1994
    Assignee: Siemens Aktiengesellschaft
    Inventors: Wolfgang Krautschneider, Klaus Lau, Lothar Risch
  • Patent number: 4966859
    Abstract: A voltage-stable sub-.mu.m-MOS transistor for VLSI circuits consist of a low-resistant silicon substrate of a first conductivity type with a high-resistant, thin, epitaxial layer of the first conductivity type situated thereon and on which a gate electrode consisting of polysilicon is disposed. Highly doped source/drain zones of the second conductivity type form a channel region of the first conductivity type. A doping substance concentration, rising in the direction of the substrate, is generated by means of double implantation, whereby the concentration maximum extends to behind the source/drain zones. A method for manufacturing same incorporates steps of forming the several layers, applying a mask, executing a double implantation in the channel region, and forming the gate electrode.
    Type: Grant
    Filed: January 3, 1989
    Date of Patent: October 30, 1990
    Assignee: Siemens Aktiengesellschaft
    Inventors: Lothar Risch, Reinhard Tielert, Wolfgang Mueller, Christoph Werner
  • Patent number: 4905193
    Abstract: A large scale integrable memory cell including a field effect transistor lying at a bit line and further including a storage capacitor which is formed by the wall of a trench and a cooperating electrode. The active region of the storage cell which lies outside the trench is fashioned in the form of a strip. The end face forms one part of the trench edge and the remaining portion of the trench edge is surrounded by a field oxide region.
    Type: Grant
    Filed: June 26, 1989
    Date of Patent: February 27, 1990
    Assignee: Siemens Aktiengesellschaft
    Inventors: Lothar Risch, Reinhard Tielert