Patents by Inventor Jeffrey W. Lutze

Jeffrey W. Lutze 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).

  • Publication number: 20080127104
    Abstract: A set non-volatile storage elements are subjected to a programming process in order to store a set of data. During the programming process, one or more verification operations are performed to determine whether the non-volatile storage elements have reached their target condition to store the appropriate data. Decisions about whether to continue programming or whether the programming is successful are made based on whether overlapping groups of the non-volatile storage elements have less than a threshold number of non-volatile storage elements that are not properly programmed.
    Type: Application
    Filed: November 27, 2006
    Publication date: May 29, 2008
    Inventors: Yan Li, Teruhiko Kamei, Jeffrey W. Lutze
  • Publication number: 20080124865
    Abstract: A memory system is disclosed that includes a set of non-volatile storage elements. Each of the non-volatile storage elements includes source/drain regions at opposite sides of a channel in a substrate and a floating gate stack above the channel. The memory system also includes a set of shield plates positioned between adjacent floating gate stacks and electrically connected to the source/drain regions for reducing coupling between adjacent floating gates. The shield plates are selectively grown on the active areas of the memory without being grown on the inactive areas. In one embodiment, the shield plates are epitaxially grown silicon positioned above the source/drain regions.
    Type: Application
    Filed: February 1, 2008
    Publication date: May 29, 2008
    Inventors: Jeffrey W. Lutze, Nima Mokhlesi
  • Publication number: 20080123426
    Abstract: A non-volatile storage system which reduces program disturb. Multiple boosting modes are implemented while programming non-volatile storage. For example, self-boosting, local self-boosting, erased area self-boosting and revised erased area self-boosting may be used. One or more switching criteria are used to determine when to switch to a different boosting mode. The boosting mode may be used to prevent program disturb in unselected NAND strings while storage elements are being programmed in selected NAND strings. By switching boosting modes, an optimal boosting mode can be used as conditions change. The boosting mode can be switched based on various criteria such as program pulse number, program pulse amplitude, program pass number, the position of a selected word line, whether coarse or fine programming is used, whether a storage element reaches a program condition and/or a number of program cycles of the non-volatile storage device.
    Type: Application
    Filed: November 2, 2006
    Publication date: May 29, 2008
    Inventors: Jeffrey W. Lutze, Yingda Dong
  • Publication number: 20080123414
    Abstract: The present invention presents a scheme for sensing memory cells. Selected memory cells are discharged through their channels to ground and then have a voltage level placed on the traditional source and another voltage level placed on the control gate, and allowing the cell bit line to charge up. The bit line of the memory cell will then charge up until the bit line voltage becomes sufficiently high to shut off any further cell conduction. The rise of the bit line voltage will occur at a rate and to a level dependent upon the data state of the cell, and the cell will then shut off when the bit line reaches a high enough level such that the body effect affected memory cell threshold is reached, at which point the current essentially shuts off. A particular embodiment performs multiple such sensing sub-operations, each with a different control gate voltage, but with multiple states being sensed in each operation by charging the previously discharged cells up through their source.
    Type: Application
    Filed: January 31, 2008
    Publication date: May 29, 2008
    Inventors: Nima Mokhlesi, Jeffrey W. Lutze
  • Publication number: 20080126676
    Abstract: A set non-volatile storage elements are subjected to a programming process in order to store a set of data. During the programming process, one or more verification operations are performed to determine whether the non-volatile storage elements have reached their target condition to store the appropriate data. Decisions about whether to continue programming or whether the programming is successful are made based on whether overlapping groups of the non-volatile storage elements have less than a threshold number of non-volatile storage elements that are not properly programmed.
    Type: Application
    Filed: November 27, 2006
    Publication date: May 29, 2008
    Inventors: Yan Li, Teruhiko Kamei, Jeffrey W. Lutze
  • Publication number: 20080123425
    Abstract: A method for operating a non-volatile storage system which reduces program disturb. Multiple boosting modes are implemented while programming non-volatile storage. For example, self-boosting, local self-boosting, erased area self-boosting and revised erased area self-boosting may be used. One or more switching criteria are used to determine when to switch to a different boosting mode. The boosting mode may be used to prevent program disturb in unselected NAND strings while storage elements are being programmed in selected NAND strings. By switching boosting modes, an optimal boosting mode can be used as conditions change. The boosting mode can be switched based on various criteria such as program pulse number, program pulse amplitude, program pass number, the position of a selected word line, whether coarse or fine programming is used, whether a storage element reaches a program condition and/or a number of program cycles of the non-volatile storage device.
    Type: Application
    Filed: November 2, 2006
    Publication date: May 29, 2008
    Inventors: Jeffrey W. Lutze, Yingda Dong
  • Patent number: 7355237
    Abstract: A memory system is disclosed that includes a set of non-volatile storage elements. Each of said non-volatile storage elements includes source/drain regions at opposite sides of a channel in a substrate and a floating gate stack above the channel. The memory system also includes a set of shield plates positioned between adjacent floating gate stacks and electrically connected to the source/drain regions for reducing coupling between adjacent floating gates. The shield plates are selectively grown on the active areas of the memory without being grown on the inactive areas. In one embodiment, the shield plates are epitaxially grown silicon positioned above the source/drain regions.
    Type: Grant
    Filed: February 13, 2004
    Date of Patent: April 8, 2008
    Assignee: Sandisk Corporation
    Inventors: Jeffrey W. Lutze, Nima Mokhlesi
  • Publication number: 20080076217
    Abstract: A nonvolatile memory array includes floating gates that have an inverted-T shape in cross section along a plane that is perpendicular to the direction along which floating cells are connected together to form a string. Adjacent strings are isolated by shallow trench isolation structures. An array having inverted-T shaped floating gates may be formed in a self-aligned manner.
    Type: Application
    Filed: September 21, 2006
    Publication date: March 27, 2008
    Inventors: Henry Chien, George Matamis, Tuan Pham, Masaaki Higashitani, Hidetaka Horiuchi, Jeffrey W. Lutze, Nima Mokhlesi, Yupin Kawing Fong
  • Publication number: 20080074920
    Abstract: A nonvolatile memory array includes floating gates that have an inverted-T shape in cross section along a plane that is perpendicular to the direction along which floating cells are connected together to form a string. Adjacent strings are isolated by shallow trench isolation structures. An array having inverted-T shaped floating gates may be formed in a self-aligned manner.
    Type: Application
    Filed: September 21, 2006
    Publication date: March 27, 2008
    Inventors: Henry Chien, George Matamis, Tuan Pham, Masaaki Higashitani, Hidetaka Horiuchi, Jeffrey W. Lutze, Nima Mokhlesi, Yupin Kawing Fong
  • Patent number: 7349264
    Abstract: The present invention presents a scheme for sensing memory cells. Selected memory cells are discharged through their channels to ground and then have a voltage level placed on the traditional source and another voltage level placed on the control gate, and allowing the cell bit line to charge up. The bit line of the memory cell will then charge up until the bit line voltage becomes sufficiently high to shut off any further cell conduction. The rise of the bit line voltage will occur at a rate and to a level dependent upon the data state of the cell, and the cell will then shut off when the bit line reaches a high enough level such that the body effect affected memory cell threshold is reached, at which point the current essentially shuts off. A particular embodiment performs multiple such sensing sub-operations, each with a different control gate voltage, but with multiple states being sensed in each operation by charging the previously discharged cells up through their source.
    Type: Grant
    Filed: December 28, 2005
    Date of Patent: March 25, 2008
    Assignee: SanDisk Corporation
    Inventors: Nima Mokhlesi, Jeffrey W. Lutze
  • Patent number: 7286406
    Abstract: The effects of bit line-to-bit line coupling in a non-volatile memory are addressed. An inhibit voltage is applied on a bit line of a storage element to be programmed to inhibit programming during a portion of a program voltage. The inhibit voltage is subsequently removed during the program voltage to allow programming to occur. Due to the proximity of bit lines, the change in the bit line voltage is coupled to a neighboring unselected bit line, reducing the neighboring bit line voltage to a level which might be sufficient to open a select gate and discharge a boost voltage. To prevent this, the select gate voltage is temporarily adjusted during the change in the bit line voltage to ensure that the biasing of the select gate on the unselected bit line is not sufficient to open the select gate.
    Type: Grant
    Filed: October 14, 2005
    Date of Patent: October 23, 2007
    Assignee: Sandisk Corporation
    Inventors: Jeffrey W. Lutze, Yan Li, Siu L. Chan
  • Patent number: 7253055
    Abstract: An array of a pillar-type nonvolatile memory cells (803) has each memory cell isolated from adjacent memory cells by a trench (810). Each memory cell is formed by a stacking process layers on a substrate: tunnel oxide layer (815), polysilicon floating gate layer (819), ONO or oxide layer (822), polysilicon control gate layer (825). Many aspects of the process are self-aligned. An array of these memory cells will require less segmentation. Furthermore, the memory cell has enhanced programming characteristics because electrons are directed at a normal or nearly normal angle (843) to the floating gate (819).
    Type: Grant
    Filed: March 29, 2006
    Date of Patent: August 7, 2007
    Assignee: SanDisk Corporation
    Inventors: Nima Mokhlesi, Jeffrey W. Lutze
  • Patent number: 7230854
    Abstract: The maximum allowable number of voltage programming pulses to program memory elements of a non-volatile memory device is adjusted to account for changes in the memory elements which occur over time. Programming pulses are applied until the threshold voltage of one or more memory elements reaches a certain verify level, after which a defined maximum number of additional pulses may be applied to other memory elements to allow them to also reach associated target threshold voltage levels. The technique enforces a maximum allowable number of programming pulses that can change over time as the memory is cycled.
    Type: Grant
    Filed: August 1, 2005
    Date of Patent: June 12, 2007
    Assignee: Sandisk Corporation
    Inventors: Jun Wan, Jeffrey W. Lutze
  • Patent number: 7218552
    Abstract: A non-volatile memory is programmed in a manner which reduces the incidence of program disturb for inhibited memory elements which undergo boosting to reduce program disturb, but which experience reduced boosting benefits due to their word line location. To achieve this result, a word line sequence in which the memory elements are programmed is adjusted so that higher word lines are programmed first, out of sequence relative to the remaining word lines. Additionally, self-boosting can be used for the higher word lines, while erased area self-boosting or a variant can be used for the remaining word lines. Furthermore, pre-charging of the channel of the inhibited memory elements may be employed prior to the self boosting, for the non-volatile storage elements which are programmed after those associated with the first word line.
    Type: Grant
    Filed: September 9, 2005
    Date of Patent: May 15, 2007
    Assignee: Sandisk Corporation
    Inventors: Jun Wan, Jeffrey W. Lutze
  • Patent number: 7215575
    Abstract: In a non-volatile semiconductor memory system (or other type of memory system), a memory cell is programmed by changing the threshold voltage of that memory cell. Because of variations in the programming speeds of different memory cells in the system, the possibility exists that some memory cells will be over programmed. That is, in one example, the threshold voltage will be moved past the intended value or range of values. The present invention includes determining whether the memory cells are over programmed.
    Type: Grant
    Filed: May 9, 2005
    Date of Patent: May 8, 2007
    Assignee: Sandisk Corporation
    Inventors: Jian Chen, Yan Li, Jeffrey W. Lutze
  • Patent number: 7206235
    Abstract: The effects of bit line-to-bit line coupling in a non-volatile memory are addressed. An inhibit voltage is applied on a bit line of a storage element to be programmed to inhibit programming during a portion of a program voltage. The inhibit voltage is subsequently removed during the program voltage to allow programming to occur. Due to the proximity of bit lines, the change in the bit line voltage is coupled to a neighboring unselected bit line, reducing the neighboring bit line voltage to a level which might be sufficient to open a select gate and discharge a boost voltage. To prevent this, the select gate voltage is temporarily adjusted during the change in the bit line voltage to ensure that the biasing of the select gate on the unselected bit line is not sufficient to open the select gate.
    Type: Grant
    Filed: October 14, 2005
    Date of Patent: April 17, 2007
    Assignee: Sandisk Corporation
    Inventors: Jeffrey W. Lutze, Yan Li, Siu L. Chan
  • Patent number: 7206231
    Abstract: The maximum allowable number of voltage programming pulses to program memory elements of a non-volatile memory device is adjusted to account for changes in the memory elements which occur over time. Programming pulses are applied until the threshold voltage of one or more memory elements reaches a certain verify level, after which a defined maximum number of additional pulses may be applied to other memory elements to allow them to also reach associated target threshold voltage levels. The technique enforces a maximum allowable number of programming pulses that can change over time as the memory is cycled.
    Type: Grant
    Filed: March 31, 2006
    Date of Patent: April 17, 2007
    Assignee: Sandisk Corporation
    Inventors: Jun Wan, Jeffrey W. Lutze
  • Patent number: 7183153
    Abstract: A method of forming an array of non-volatile memory cells includes forming a plurality of floating gate structures and shaping the plurality of floating gate structures to reduce the width of upper parts of floating gate structures. A first process forms floating gates by etching an upper portion of a polysilicon structure with masking elements in place to shape the floating gate. A second process etches recesses and protrusions in a polysilicon structure prior to etching the structure to form individual floating gates.
    Type: Grant
    Filed: March 12, 2004
    Date of Patent: February 27, 2007
    Assignee: SanDisk Corporation
    Inventors: Jeffrey W. Lutze, Tuan Pham, Masaaki Higashitani
  • Patent number: 7177199
    Abstract: The process for programming a set of memory cells is improved by adapting the programming process based on behavior of the memory cells. For example, a set of program pulses is applied to the word line for a set of flash memory cells. A determination is made as to which memory cells are easier to program and which memory cells are harder to program. Bit line voltages (or other parameters) can be adjusted based on the determination of which memory cells are easier to program and which memory cells are harder to program. The programming process will then continue with the adjusted bit line voltages (or other parameters).
    Type: Grant
    Filed: October 20, 2003
    Date of Patent: February 13, 2007
    Assignee: Sandisk Corporation
    Inventors: Jian Chen, Jeffrey W. Lutze, Yan Li, Daniel C. Guterman, Tomoharu Tanaka
  • Patent number: 7170788
    Abstract: A non-volatile memory is programmed in a manner which reduces the incidence of program disturb for inhibited memory elements which undergo boosting to reduce program disturb, but which experience reduced boosting benefits due to their word line location. To achieve this result, a word line sequence in which the memory elements are programmed is adjusted so that higher word lines are programmed first, out of sequence relative to the remaining word lines. Additionally, self-boosting can be used for the higher word lines, while erased area self-boosting or a variant can be used for the remaining word lines. Furthermore, pre-charging of the channel of the inhibited memory elements may be employed prior to the self boosting, for the non-volatile storage elements which are programmed after those associated with the first word line.
    Type: Grant
    Filed: September 9, 2005
    Date of Patent: January 30, 2007
    Assignee: Sandisk Corporation
    Inventors: Jun Wan, Jeffrey W. Lutze