Patents Assigned to T-Ram Semiconductor, Inc.
  • Patent number: 8324656
    Abstract: Embodiments of integrated circuits for mitigating against electrostatic coupling are described. In an embodiment, first gate dielectrics are respectively located over first active regions. First isolation regions are respectively located between the first active regions. Second gate dielectrics are respectively located over second active regions. Second isolation regions are respectively located between the second active regions. In an embodiment, the first active regions are approximately 20 to 80 percent shorter in height/thickness than the second active regions. In another embodiment, the first isolation regions extend above an uppermost surface of the first gate dielectrics while providing gaps between the first isolation regions and sidewalls of the first active regions for receipt of material used in formation of conductive lines. In yet another embodiment, active area stripes are narrower in width at p-base regions and n-base regions than at cathode regions and anode regions respectively thereof.
    Type: Grant
    Filed: July 1, 2011
    Date of Patent: December 4, 2012
    Assignee: T-RAM Semiconductor, Inc.
    Inventors: Rajesh N. Gupta, Marc Laurent Tarabbia, Kevin J. Yang
  • Patent number: 8174046
    Abstract: Method and apparatus for an integrated circuit having memory including thyristor-based memory cells is described. A pair of the thyristor-based memory cells are commonly coupled via a bitline region, where a parasitic bipolar junction transistor is defined therebetween responsive to the bitline region being common. In another implementation, the pair of the thyristor-based memory cells are commonly coupled via the anode region, where a parasitic bipolar junction transistor is defined therebetween responsive to the anode region being common. The common bitline or anode region, respectively, has a locally thinned region to inhibit charge transfer between the pair via the parasitic bipolar junction transistor. Moreover, a method for forming a field-effect transistor on a silicon-on-insulator wafer is described, where charge transfer facilitated by a parasitic bipolar transistor is reduced responsive to an increase in dopants at least proximate to an insulator layer.
    Type: Grant
    Filed: February 23, 2006
    Date of Patent: May 8, 2012
    Assignee: T-RAM Semiconductor, Inc
    Inventors: Marc Laurent Tarabbia, Maxim Ershov, Rajesh N. Gupta
  • Patent number: 8093107
    Abstract: A thyristor based semiconductor device includes a thyristor having cathode, P-base, N-base and anode regions disposed in electrical series relationship. The N-base region for the thyristor has a cross-section that defines an inverted “T” shape, wherein a buried well in semiconductor material forms is operable as a part of the N-base. The stem to the inverted “T” shape extends from the upper surface of the semiconductor material to the buried well. The P-base region for the thyristor extends laterally outward from a side of the stem that is opposite the anode region of the thyristor, and is further bounded between the buried well and a surface of the semiconductor material. A thinned portion for the N-base is defined between the cathode region of the thyristor and the buried well, and may include supplemental dopant of concentration greater than that for some other portion of the N-base.
    Type: Grant
    Filed: November 14, 2008
    Date of Patent: January 10, 2012
    Assignee: T-RAM Semiconductor, Inc.
    Inventors: Farid Nemati, Scott Robins, Kevin J. Yang
  • Patent number: 8069385
    Abstract: A PBIST architecture is described. A data path circuit is configured for bit-to-associated bit comparisons of expected result data read from a tile with the expected result data read from result memory. The data path circuit is configured to write a first type of failure indication to first failure memory responsive to a data 0 being read from the result memory and a data 1 being read from the tile for a bit-to-associated bit comparison failure. The data path circuit is further configured to write a second type of failure indication to second failure memory responsive to a data 1 being read from the result memory and a data 0 being read from the tile for the bit-to-associated bit comparison.
    Type: Grant
    Filed: July 13, 2009
    Date of Patent: November 29, 2011
    Assignee: T-RAM Semiconductor, Inc.
    Inventor: Rajesh Chopra
  • Patent number: 8017998
    Abstract: Gettering contaminants for formation of integrated circuits on a semiconductor-on-insulator structure is described. A semiconductor-on-insulator structure is configured to attract contaminants. Contaminant attractor regions are formed using ion implantation into a semiconductor layer of the semiconductor-on-insulator structure. The semiconductor layer is located above a buried insulator layer of the semiconductor-on-insulator structure. The contaminant attractor regions are spaced away from active regions. Tiles are located on an upper surface of the buried insulator layer. The contaminant attractor regions are formed adjacent to, in close proximity to, or in the tiles. At least one dielectric layer laterally adjacent to the tiles and is disposed on the upper surface of the buried insulator layer. The at least one dielectric layer at least inhibits lateral migration of contaminants to the active regions.
    Type: Grant
    Filed: September 8, 2009
    Date of Patent: September 13, 2011
    Assignee: T-RAM Semiconductor, Inc.
    Inventors: Srinivasa R. Banna, Scott Robins
  • Patent number: 7969777
    Abstract: A new memory cell can contain only a single thyristor. There is no need to include an access transistor in the cell. In one embodiment, the thyristor is a thin capacitively coupled thyristor. The new memory cell can be connected to word, bit, and control lines in several ways to form different memory arrays. Timing and voltage levels of word, bit and control lines are disclosed.
    Type: Grant
    Filed: December 1, 2008
    Date of Patent: June 28, 2011
    Assignee: T-RAM Semiconductor, Inc.
    Inventors: Hyun-Jin Cho, Farid Nemati
  • Patent number: 7968381
    Abstract: A semiconductor device having a thyristor-based device and a pass device exhibits characteristics that may include, for example, resistance to short channel effects that occur when conventional MOSFET devices are scaled smaller in connection with advancing technology. According to an example embodiment of the present invention, the semiconductor device includes a pass device having a channel in a fin portion over a semiconductor substrate, and a thyristor device coupled to the pass device. The fin has a top portion and a side portion and extends over the semiconductor substrate. The pass device includes source/drain regions separated by the channel and a gate facing and capacitively coupled to the side portion of the fin that includes the channel. The thyristor device includes anode and cathode end portions, each end portion having base and emitter regions, where one of the emitter regions is coupled to one of the source/drain regions of the pass device.
    Type: Grant
    Filed: October 16, 2006
    Date of Patent: June 28, 2011
    Assignee: T-RAM Semiconductor, Inc.
    Inventors: Andrew Horch, Scott Robins
  • Patent number: 7961540
    Abstract: A dynamically-operating restoration circuit is used to apply a voltage or current restore pulse signal to thyristor-based memory cells and therein restore data in the cell using the internal positive feedback loop of the thyristor. In one example implementation, the internal positive feedback loop in the thyristor is used to restore the conducting state of a device after the thyristor current drops below the holding current. A pulse and/or periodic waveform are defined and applied to ensure that the thyristor is not released from its conducting state. The time average of the periodic restore current in the thyristor may be lower than the holding current threshold. While not necessarily limited to memory cells that are thyristor-based, various embodiments of the invention have been found to be the particularly useful for high-speed, low-power memory cells in which a thin capacitively-coupled thyristor is used to provide a bi-stable storage element.
    Type: Grant
    Filed: July 29, 2008
    Date of Patent: June 14, 2011
    Assignee: T-RAM Semiconductor, Inc.
    Inventors: Farid Nemati, Hyun-Jin Cho, Robert Homan Igehy
  • Patent number: 7897440
    Abstract: A semiconductor device may comprise a plurality of memory cells. A memory cell may comprise a thyristor, at least a portion of which is formed in a pillar of semiconductor material. The pillar may comprise sidewalls defining a cylindrical circumference of a first diameter. In a particular embodiment, the pillars associated with the plurality of memory cells may define rows and columns of an array. In a further embodiment, a pillar may be spaced by a first distance of magnitude up to the first diameter relative to a neighboring pillar within its row. In an additional further embodiment, the pillar may be spaced by a second distance of a magnitude up to twice the first diameter, relative to a neighboring pillar within its column.
    Type: Grant
    Filed: November 24, 2008
    Date of Patent: March 1, 2011
    Assignee: T-RAM Semiconductor, Inc.
    Inventor: Andrew E. Horch
  • Patent number: 7893456
    Abstract: A thyristor-based memory may comprise a thyristor accessible via an access transistor. A temperature dependent bias may be applied to at least one of a supporting substrate and an electrode capacitively-coupled to a base region of the thyristor. The voltage level of the adaptive bias may change with respect to temperature and may influence and/or compensate an inherent bipolar gain of the thyristor in accordance with the change in bias and may enhance its performance and/or reliability over a range of operating temperature. In a particular embodiment, the thyristor may be formed in a layer of silicon of an SOI substrate and the adaptive bias coupled to a supporting substrate of the SOI structure.
    Type: Grant
    Filed: February 9, 2009
    Date of Patent: February 22, 2011
    Assignee: T-RAM Semiconductor, Inc.
    Inventors: Farid Nemati, Kevin J. Yang
  • Patent number: 7894255
    Abstract: A new memory cell contains only a single thyristor without the need to include an access transistor. A memory array containing these memory cells can be fabricated on bulk silicon wafer. Each memory cell is separated from other memory cells by shallow trench isolation regions. The memory cell comprises a thyristor body and a gate. The thyristor body has two end region and two base regions. The gate is positioned over and insulated from at least a portion of one base region and offset from another base region. A first end region is connected to one of a word line, a bit line and a third line. A second end region is connected to another of the word line, bit line, and third line. The gate is connected to the remaining of the word line, bit line and third line.
    Type: Grant
    Filed: July 25, 2007
    Date of Patent: February 22, 2011
    Assignee: T-RAM Semiconductor, Inc.
    Inventors: Farid Nemati, Scott Robins, Kevin J. Yang
  • Patent number: 7894256
    Abstract: A new memory cell contains only a single thyristor without the need to include an access transistor. A memory array containing these memory cells can be fabricated on bulk silicon wafer. The memory cell contains a thyristor body and a gate. The thyristor body has two end region and two base regions, and it is disposed on top of a well. The memory cell is positioned between two isolation regions, and the isolation regions are extended below the well. A first end region is connected to one of a word line, a bit line and a third line. A second end region is connected to another of the word line, bit line, and third line. The gate is connected to the remaining of the word line, bit line and third line.
    Type: Grant
    Filed: July 25, 2007
    Date of Patent: February 22, 2011
    Assignee: T-RAM Semiconductor, Inc.
    Inventors: Farid Nemati, Scott Robins, Kevin J. Yang
  • Patent number: 7858449
    Abstract: In a method of fabricating a semiconductor memory device, a thyristor may be formed in a layer of semiconductor material. Carbon may be implanted and annealed in a base-emitter junction region for the thyristor to affect leakage characteristics. The density of the carbon and/or a bombardment energy and/or an anneal therefore may be selected to establish a low-voltage, leakage characteristic for the junction substantially greater than its leakage absent the carbon. In one embodiment, an anneal of the implanted carbon may be performed in common with an activation for other implant regions the semiconductor device.
    Type: Grant
    Filed: February 9, 2009
    Date of Patent: December 28, 2010
    Assignee: T-RAM Semiconductor, Inc.
    Inventors: Kevin J. Yang, Farid Nemati, Scott Robins, James D. Plummer, Hyun-Jin Cho
  • Patent number: 7859929
    Abstract: Sense logic, and associated signaling, for dynamic thyristor-based memory cells is described. A first supply voltage level is greater than a second supply voltage level. In an embodiment, cross-coupled inverters of a sense amplifier are operatively coupled between a ground node and the second supply for sensing voltage. The first supply voltage is pass gate coupled to a first sense node and a second sense node. The pass gating is responsive to sample signaling. A first supply transistor is gated by a transfer bus. A second supply transistor is gated by a sense reference voltage that is between the first supply voltage level and the second supply voltage level. Each of the first supply transistor and the second supply transistor is back body biased with a write voltage level that is between the second supply voltage level and the ground voltage level.
    Type: Grant
    Filed: April 10, 2009
    Date of Patent: December 28, 2010
    Assignee: T-RAM Semiconductor, Inc.
    Inventor: Richard Roy
  • Patent number: 7859011
    Abstract: A semiconductor device may comprise a partially-depleted SOI MOSFET having a floating body region disposed between a source and drain. The floating body region may be driven to receive injected carriers for adjusting its potential during operation of the MOSFET. In a particular case, the MOSFET may comprise another region of semiconductor material in contiguous relationship with a drain/source region of the MOSFET and on a side thereof opposite to the body region. This additional region may be formed with a conductivity of type opposite the drain/source, and may establish an effective bipolar device per the body, the drain/source and the additional region. The geometries and doping thereof may be designed to establish a transport gain of magnitude sufficient to assist the injection of carriers into the floating body region, yet small enough to guard against inter-latching with the MOSFET.
    Type: Grant
    Filed: February 9, 2009
    Date of Patent: December 28, 2010
    Assignee: T-RAM Semiconductor, Inc.
    Inventors: Zachary K. Lee, Farid Nemati, Scott Robins
  • Patent number: 7804107
    Abstract: In a method of processing a semiconductor device, a silicide-blocking layer may be formed over a semiconductor material. After defining the silicide-blocking layer, impurities may be implanted into portions of the semiconductor material as defined by the silicide-blocking layer. After the implant, silicide may be formed in a surface region of the semiconductor material as permitted by the silicide-blocking layer. Regions of the impurity implant may comprise boundaries that are related to the outline of the silicide formed thereover. In a further embodiment, the implant may define a base region to a thyristor device. The implant may be performed with an angle of incidence to extend portions of the base region beneath a peripheral edge of the blocking mask. Next, an anode-emitter region may be formed using an implant of a substantially orthogonal angle of incidence and self-aligned to the mask.
    Type: Grant
    Filed: October 3, 2007
    Date of Patent: September 28, 2010
    Assignee: T-RAM Semiconductor, Inc.
    Inventors: Andrew E. Horch, Fred Hause
  • Patent number: 7786505
    Abstract: Formation of a thyristor-based memory cell is described. A first gate dielectric of the storage element is formed over a base region thereof located in a silicon layer. A transistor is coupled to the storage element via a cathode region located in the silicon layer. The transistor has a gate electrode formed over a second gate dielectric. A spacer is formed at least in part along a sidewall of the gate electrode facing a gate electrode of the storage element. A shallow implant region is formed in the silicon layer responsive at least in part to the spacer. The spacer offsets the shallow implant region from the sidewall. A portion of the shallow implant region is for an extension region. The first gate dielectric and the second gate dielectric are formed at least in part by deposition of a dielectric material.
    Type: Grant
    Filed: December 16, 2005
    Date of Patent: August 31, 2010
    Assignee: T-RAM Semiconductor, Inc.
    Inventors: Kevin J. Yang, Hyun-Jin Cho
  • Patent number: 7738274
    Abstract: A content-addressable memory (“CAM”) architecture and method for reducing power consumption thereof are described. A CAM cell array includes CAM cells, each of which includes two thyristor-based storage elements. Each thyristor-based storage element of the CAM cells has a control gate, an anode, and a cathode for providing control gates, anodes, and cathodes of the CAM cells. The CAM cell array further includes matchlines directly coupled to the cathodes of the CAM cells; searchlines directly coupled to the anodes of the CAM cell; and gatelines coupled to the control gates of the CAM cells.
    Type: Grant
    Filed: March 27, 2008
    Date of Patent: June 15, 2010
    Assignee: T-RAM Semiconductor, Inc.
    Inventors: Farid Nemati, Bruce Lynn Bateman
  • Patent number: 7592642
    Abstract: A thyristor-based memory device may comprise two base regions of opposite type conductivity formed between a cathode-emitter region and an anode-emitter region. A junction defined between the p-base region and the cathode-emitter region of the thyristor may be “treated” with a high ionization energy acceptor such as indium in combination with carbon as an activation assist species. These two implants may form complexes that may extend across the junction region.
    Type: Grant
    Filed: April 4, 2006
    Date of Patent: September 22, 2009
    Assignee: T-RAM Semiconductor, Inc.
    Inventors: Srinivasa R. Banna, James D. Plummer
  • Patent number: 7587643
    Abstract: An integrated circuit may include a packet decoder to receive serial data and to decode JTAG signals from the packets received. A JTAG processor may test the electrical circuitry dependent on the JTAG signals decoded. In a further embodiment, a test system may include a library of selectable JTAG routines. An encoder may encode a signal with serial data representative of sequential JTAG signals for at least one of the selectable JTAG routines. In a method of testing, the integrated circuit may receive the serial data signal at a predetermined terminal. A portion of the serial data may be examined to determine the presence of a predefined signature key. JTAG data may then be parsed from the serial data and tests performed based on the parsed JTAG data.
    Type: Grant
    Filed: August 25, 2005
    Date of Patent: September 8, 2009
    Assignee: T-RAM Semiconductor, Inc.
    Inventor: Rajesh Chopra