Patents by Inventor Dana Lee

Dana Lee 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: 20100259988
    Abstract: A plurality of non-volatile storage elements on a common active layer are offset from neighbor non-volatile storage elements. This offsetting of non-volatile storage elements helps reduce interference from neighbor non-volatile storage elements. A method of manufacture is also described for fabricating the offset non-volatile storage elements.
    Type: Application
    Filed: June 24, 2010
    Publication date: October 14, 2010
    Inventors: Jeffrey W. Lutze, Dana Lee
  • Publication number: 20100259987
    Abstract: Techniques are disclosed herein for erasing non-volatile memory cells. The memory cells are erased using a trial erase pulse. A suitable magnitude for a second pulse is determined based on the magnitude of the trial erase pulse and data collected about the threshold voltage distribution after the trial erase. The second erase pulse is used to erase the memory cells. In one implementation, the threshold voltages of the memory cells are not verified after the second erase. Soft programming after the second erase may be performed. The magnitude of the soft programming pulse may be determined based on the trial erase pulse. In one implementation, the memory cells' threshold voltages are not verified after the soft programming. Limiting the number of erase pulses and soft programming pulses saves time and power. Determining an appropriate magnitude for the second erase pulse minimizes or eliminates over-erasing.
    Type: Application
    Filed: April 9, 2009
    Publication date: October 14, 2010
    Inventors: Dana Lee, Nima Mokhlesi, Anubhav Khandelwal
  • Publication number: 20100261317
    Abstract: A plurality of non-volatile storage elements on a common active layer are offset from neighbor non-volatile storage elements. This offsetting of non-volatile storage elements helps reduce interference from neighbor non-volatile storage elements. A method of manufacture is also described for fabricating the offset non-volatile storage elements.
    Type: Application
    Filed: June 24, 2010
    Publication date: October 14, 2010
    Inventors: Jeffrey W. Lutze, Dana Lee
  • Publication number: 20100259989
    Abstract: A plurality of non-volatile storage elements on a common active layer are offset from neighbor non-volatile storage elements. This offsetting of non-volatile storage elements helps reduce interference from neighbor non-volatile storage elements. A method of manufacture is also described for fabricating the offset non-volatile storage elements.
    Type: Application
    Filed: June 24, 2010
    Publication date: October 14, 2010
    Inventors: Jeffrey W. Lutze, Dana Lee
  • Patent number: 7808839
    Abstract: A split gate NAND flash memory structure is formed on a semiconductor substrate of a first conductivity type. The NAND structure comprises a first region of a second conductivity type in the substrate with a second region of the second conductivity type in the substrate, spaced apart from the first region. A continuous first channel region is defined between the first region and the second region. A plurality of floating gates are spaced apart from one another with each positioned over a separate portion of the channel region. A plurality of control gates are provided with each associated with and adjacent to a floating gate. Each control gate has two portions: a first portion over a portion of the channel region and a second portion over the associated floating gate and capacitively coupled thereto.
    Type: Grant
    Filed: June 6, 2007
    Date of Patent: October 5, 2010
    Assignee: Silicon Storage Technology, Inc.
    Inventors: Yuniarto Widjaja, John W. Cooksey, Changyuan Chen, Feng Gao, Ya-Fen Lin, Dana Lee
  • Patent number: 7800956
    Abstract: Programming time is reduced in a non-volatile memory in a multi-pass programming process. In a first programming pass, high state cells are programmed by a sequence of program pulses to identify fast and slow high state cells, while lower state cells are locked out from programming. Once identified, the fast high state cells are temporarily locked out from programming while the slow high state cells continue being programmed to their final intended state. Further, the program pulses are sharply stepped up to program the slow high state cells. In a second programming pass, the fast high state cells are programmed along with the other, lower state cells, until they all reach their respective intended states. A time savings is realized compared to approaches in which all high state cells are programmed in the first programming pass.
    Type: Grant
    Filed: June 27, 2008
    Date of Patent: September 21, 2010
    Assignee: Sandisk Corporation
    Inventors: Dana Lee, Deepanshu Dutta, Yingda Dong
  • Publication number: 20100220533
    Abstract: Nonvolatile flash memory systems and methods are disclosed having a semiconductor substrate of a first conductivity type, including non-diffused channel regions through which electron flow is induced by application of voltage to associated gate elements. A plurality of floating gates are spaced apart from one another and each insulated from the channel region. A plurality of control gates are spaced apart from one another and insulated from the channel region, with each control gate being located between a first floating gate and a second floating gate and capacitively coupled thereto to form a subcell. A plurality of spaced-apart assist gates are insulated from the channel region, with each assist gate being located between and insulated from adjacent subcells. The channel is formed of three regions, two beneath adjacent control gate elements as well as a third region between the first two and beneath an associated assist gate.
    Type: Application
    Filed: May 4, 2010
    Publication date: September 2, 2010
    Inventors: Changyuan Chen, Ya-Fen Lin, Dana Lee
  • Patent number: 7764547
    Abstract: Techniques are presented for dealing with possible source line bias is an error introduced by a non-zero resistance in the ground loop of the read/write circuits of a non-volatile memory. The error is caused by a voltage drop across the resistance of the source path to the chip's ground when current flows. For this purpose, the memory device includes a source potential regulation circuit, including an active circuit element having a first input connected to a reference voltage and having a second input connected as a feedback loop that is connectable to the aggregate node from which the memory cells of a structural block have their current run to ground. A variation includes a non-linear resistive element connectable between the aggregate node and ground.
    Type: Grant
    Filed: December 20, 2007
    Date of Patent: July 27, 2010
    Assignee: SanDisk Corporation
    Inventors: Dana Lee, Nima Mokhlesi, Deepak Chandra Sekar
  • Patent number: 7760547
    Abstract: A plurality of non-volatile storage elements on a common active layer are offset from neighbor non-volatile storage elements. This offsetting of non-volatile storage elements helps reduce interference from neighbor non-volatile storage elements. A method of manufacture is also described for fabricating the offset non-volatile storage elements.
    Type: Grant
    Filed: September 25, 2007
    Date of Patent: July 20, 2010
    Assignee: SanDisk Corporation
    Inventors: Jeffrey W. Lutze, Dana Lee
  • Patent number: 7749779
    Abstract: A landing pad for use as a contact to a conductive spacer adjacent a structure in a semiconductor device comprises two islands, each of which is substantially rectangularly shaped and is spaced apart from one another and from the structure. Conductive spacers are adjacent to each island and overlapping each other and overlapping with the conductive spacer adjacent to the structure. The contact to the landing pad is on the conductive spacers adjacent to the islands and spaced apart from the structure.
    Type: Grant
    Filed: November 6, 2008
    Date of Patent: July 6, 2010
    Assignee: Silicon Storage Technology, Inc.
    Inventors: Dana Lee, Wen-Juei Lu, Felix Ying-Kit Tsui
  • Patent number: 7723774
    Abstract: Nonvolatile flash memory systems and methods are disclosed having a semiconductor substrate of a first conductivity type, including non-diffused channel regions through which electron flow is induced by application of voltage to associated gate elements. A plurality of floating gates are spaced apart from one another and each insulated from the channel region. A plurality of control gates are spaced apart from one another and insulated from the channel region, with each control gate being located between a first floating gate and a second floating gate and capacitively coupled thereto to form a subcell. A plurality of spaced-apart assist gates are insulated from the channel region, with each assist gate being located between and insulated from adjacent subcells. The channel is formed of three regions, two beneath adjacent control gate elements as well as a third region between the first two and beneath an associated assist gate.
    Type: Grant
    Filed: July 10, 2007
    Date of Patent: May 25, 2010
    Assignee: Silicon Storage Technology, Inc.
    Inventors: Changyuan Chen, Ya-Fen Lin, Dana Lee
  • Patent number: 7706189
    Abstract: To program one or more non-volatile storage elements, a set of programming pulses are applied to at least one selected non-volatile storage element and one or more particular unselected non-volatile storage elements, for example, via a common word line. A boosting voltage is applied to other unselected non-volatile storage elements during the programming process in order to boost the channels of the unselected non-volatile storage elements so that programming will be inhibited. Each of the programming pulses has a first intermediate magnitude, a second intermediate magnitude and a third magnitude. In one embodiment, the first intermediate magnitude is similar to or the same as the boosting voltage. The second intermediate magnitude is greater than the first intermediate magnitude, but less then the third magnitude. Such an arrangement can reduce the effects of program disturb.
    Type: Grant
    Filed: May 25, 2007
    Date of Patent: April 27, 2010
    Assignee: SanDisk Corporation
    Inventors: Yingda Dong, Jeffrey W. Lutze, Dana Lee
  • Patent number: 7656703
    Abstract: To program one or more non-volatile storage elements, a set of programming pulses are applied to at least one selected non-volatile storage element and one or more particular unselected non-volatile storage elements, for example, via a common word line. A boosting voltage is applied to other unselected non-volatile storage elements during the programming process in order to boost the channels of the unselected non-volatile storage elements so that programming will be inhibited. Each of the programming pulses has a first intermediate magnitude, a second intermediate magnitude and a third magnitude. In one embodiment, the first intermediate magnitude is similar to or the same as the boosting voltage. The second intermediate magnitude is greater than the first intermediate magnitude, but less then the third magnitude. Such an arrangement can reduce the effects of program disturb.
    Type: Grant
    Filed: May 25, 2007
    Date of Patent: February 2, 2010
    Assignee: SanDisk Corporation
    Inventors: Yingda Dong, Jeffrey W. Lutze, Dana Lee
  • Publication number: 20100006915
    Abstract: A memory system is disclosed that includes a set of non-volatile storage elements. A given memory cell has a dielectric cap above the floating gate. In one embodiment, the dielectric cap resides between the floating gate and a conformal IPD layer. The dielectric cap reduces the leakage current between the floating gate and a control gate. The dielectric cap achieves this reduction by reducing the strength of the electric field at the top of the floating gate, which is where the electric field would be strongest without the dielectric cap for a floating gate having a narrow stem.
    Type: Application
    Filed: July 9, 2008
    Publication date: January 14, 2010
    Inventors: Dana Lee, Henry Chin, James K. Kai, Takashi Whitney Orimoto, Vinod R. Purayath, George Matamis
  • Publication number: 20100009503
    Abstract: A method of fabricating a memory system is disclosed that includes a set of non-volatile storage elements. The method includes forming a floating gate having a top and at least two sides. A dielectric cap is formed at the top of the floating gate. An inter-gate dielectric layer is formed around the at least two sides of the floating gate and over the top of the dielectric cap. A control gate is formed over the top of the floating gate, the inter-gate dielectric layer separates the control gate from the floating gate. In one aspect, forming the dielectric cap includes implanting oxygen in the top of the floating gate and heating the floating gate to form the dielectric cap from the implanted oxygen and silicon from which the floating gate was formed.
    Type: Application
    Filed: July 9, 2008
    Publication date: January 14, 2010
    Inventors: James K. Kai, Dana Lee, Takashi Whitney Orimoto, Vinod R. Purayath, George Matamis, Henry Chin
  • Publication number: 20090323429
    Abstract: Programming time is reduced in a non-volatile memory in a multi-pass programming process. In a first programming pass, high state cells are programmed by a sequence of program pulses to identify fast and slow high state cells, while lower state cells are locked out from programming. Once identified, the fast high state cells are temporarily locked out from programming while the slow high state cells continue being programmed to their final intended state. Further, the program pulses are sharply stepped up to program the slow high state cells. In a second programming pass, the fast high state cells are programmed along with the other, lower state cells, until they all reach their respective intended states. A time savings is realized compared to approaches in which all high state cells are programmed in the first programming pass.
    Type: Application
    Filed: June 27, 2008
    Publication date: December 31, 2009
    Inventors: Dana Lee, Deepanshu Dutta, Yingda Dong
  • Patent number: 7623389
    Abstract: System for programming a selected non-volatile memory cell in a memory array having a gate node coupled to a wordline WL(n) and a drain node connected to a selected bitline by injecting hot carriers from a drain region of an injecting memory cell having a gate node coupled to a next neighbor wordline WL(n?1) into a floating gate of the selected non-volatile memory cell on the wordline WL(n).
    Type: Grant
    Filed: December 21, 2006
    Date of Patent: November 24, 2009
    Assignee: SanDisk Corporation
    Inventors: Dana Lee, Jeffrey Lutze
  • Patent number: 7577034
    Abstract: A corrective action is taken to adjust for nonlinearities in a program voltage which is applied to a selected word line in a memory device. The nonlinearities result in a non-uniform program voltage step size which can cause over programming or slow programming. A digital to analog converter (DAC) which provides the program voltages can have a nonlinear output, such as when certain code words are input to the DAC. The memory device can be tested beforehand to determine where the nonlinearities occur, and configured to take corrective action when the corresponding code words are input. For example, the DAC may have a nonlinear output when a rollover code word is input, e.g., a when a string of least significant bits in successive code words change from 1's to 0's. The corrective action can include repeating a prior program pulse or adjusting a duration of a program pulse.
    Type: Grant
    Filed: September 26, 2007
    Date of Patent: August 18, 2009
    Assignee: SanDisk Corporation
    Inventors: Dana Lee, Jun Wan
  • Publication number: 20090161433
    Abstract: Techniques are presented for dealing with possible source line bias is an error introduced by a non-zero resistance in the ground loop of the read/write circuits of a non-volatile memory. The error is caused by a voltage drop across the resistance of the source path to the chip's ground when current flows. For this purpose, the memory device includes a source potential regulation circuit, including an active circuit element having a first input connected to a reference voltage and having a second input connected as a feedback loop that is connectable to the aggregate node from which the memory cells of a structural block have their current run to ground. A variation includes a non-linear resistive element connectable between the aggregate node and ground.
    Type: Application
    Filed: December 20, 2007
    Publication date: June 25, 2009
    Inventors: Dana Lee, Nima Mokhlesi, Deepak Chandra Sekar
  • Patent number: 7544569
    Abstract: A split gate NAND flash memory structure is formed on a semiconductor substrate of a first conductivity type. The NAND structure comprises a first region of a second conductivity type and a second region of the second conductivity type in the substrate, spaced apart from the first region, thereby defining a channel region therebetween. A plurality of floating gates are spaced apart from one another and each is insulated from the channel region. A plurality of control gates are spaced apart from one another, with each control gate insulated from the channel region. Each of the control gate is between a pair of floating gates and is capacitively coupled to the pair of floating gates. A plurality of select gates are spaced apart from one another, with each select gate insulated from the channel region. Each select gate is between a pair of floating gates.
    Type: Grant
    Filed: September 5, 2006
    Date of Patent: June 9, 2009
    Assignee: Silicon Storage Technology, Inc.
    Inventors: Feng Gao, Ya-Fen Lin, John W. Cooksey, Changyuan Chen, Yuniarto Widjaja, Dana Lee