Patents by Inventor Yimao Cai

Yimao Cai 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: 8633465
    Abstract: The present invention discloses a multilevel resistive memory having large storage capacity, which belongs to a field of a fabrication technology of a resistive memory. The resistive memory includes an top electrode and a bottom electrode, and a combination of a plurality of switching layers and defective layers interposed between the top electrode and the bottom electrode, wherein, the top electrode and the bottom electrode are respectively contacted with a switching layer (a film such as Ta2O5, TiO2, HfO2), and the defective layers (metal film such as Ti, Au, Ag) are interposed between the switching layers. By using the present invention, a storage capacity of a resistive memory can be increased.
    Type: Grant
    Filed: February 8, 2012
    Date of Patent: January 21, 2014
    Assignee: Peking University
    Inventors: Ru Huang, Gengyu Yang, Yimao Cai, Yu Tang, Lijie Zhang, Yue Pan, Shenghu Tan, Yinglong Huang
  • Publication number: 20140017870
    Abstract: Disclosed herein is a method for inhibiting a programming disturbance of a flash memory, which relates to a technical field of a non-volatile memory in ultra-large-scale integrated circuit fabrication technologies. In the present invention, an dopant gradient of a PN junction between a substrate and a drain is reduced by adding a step of performing an angled ion implantation of donor dopants into a standard process for a flash memory, so that an electric field of the PN junction between the substrate and the drain is reduced, and consequently the programming disturbance is inhibited. Meanwhile, a dopant gradient of the PN junction between a channel and the drain is maintained, so that an electric field of the PN junction between the channel and the drain, which is necessary for programming, is maintained, and thus the programming efficiency and the programming speed can be ensured.
    Type: Application
    Filed: October 28, 2011
    Publication date: January 16, 2014
    Applicant: PEKING UNIVERSITY
    Inventors: Yimao Cai, Ru Huang
  • Patent number: 8593848
    Abstract: The invention provides a flash memory array structure and a method for programming the same, which relates to a technical field of nonvolatile memories in ultra large scale integrated circuit fabrication technology. The flash memory array of the present invention includes memory cells, word lines and bit lines connected to the memory cells, wherein the word lines connected to control gates of the memory cells and the bit lines connected to drain terminals of the memory cells are not perpendicular to each other but cross each other at an angle; the control gates of two memory cells adjacent to each other along the channel direction between every two bit lines are controlled by two word lines, respectively, drain terminals thereof are controlled by two bit lines, respectively, and source terminals thereof are shared. The present invention also provides a method for programming the flash memory array structure, which can realize a programming with low power consumption.
    Type: Grant
    Filed: April 21, 2011
    Date of Patent: November 26, 2013
    Assignee: Peking University
    Inventors: Yimao Cai, Ru Huang, Poren Tang, Shiqiang Qin
  • Patent number: 8536639
    Abstract: The present invention discloses a floating gate structure of a flash memory device and a method for fabricating the same, which relates to a nonvolatile memory in a manufacturing technology of an ultra-large-scaled integrated circuit. In the invention, by modifying a manufacturing of a floating gate in the a standard process for the flash memory, that is, by adding three steps of deposition, two steps of etching and one step of CMP, an -shaped floating gate is formed. In addition to these steps, all the other steps are the same as those of the standard process for the flash memory process. By the invention, a coupling ratio may be improved effectively and a crosstalk between adjacent devices may be lowered, without adding additional photomasks and barely increasing a process complexity, which are very important to improve programming speed and reliability.
    Type: Grant
    Filed: November 30, 2011
    Date of Patent: September 17, 2013
    Assignee: Peking University
    Inventors: Yimao Cai, Song Mei, Ru Huang
  • Patent number: 8526242
    Abstract: The present invention discloses a flash memory and the fabrication method and the operation method for the same. The flash memory comprises two memory cells of vertical channels, wherein a lightly-doped N type (or P type) silicon is used as a substrate; a P+ region (or an N+ region) is provided on each of the both ends of the silicon surface, and two channel regions perpendicular to the surface are provided therebetween; an N+ region (or a P+ region) shared by two channels is provided over the channels; a tunneling oxide layer, a polysilicon floating gate, a block oxide layer and a polysilicon control gate are provided sequentially on the outer sides of each channel from inside to outside; and the polysilicon floating gate and the polysilicon control gate are isolated from the P+ region by a sidewall oxide layer. The whole device is a two-bit TFET type flash memory with vertical channels which has better compatibility with prior-art standard CMOS process.
    Type: Grant
    Filed: March 7, 2011
    Date of Patent: September 3, 2013
    Assignee: Peking University
    Inventors: Ru Huang, Yimao Cai, Shiqiang Qin, Qianqian Huang, Poren Tang, Yu Tang, Gengyu Yang
  • Publication number: 20130217199
    Abstract: The present invention discloses a method for fabricating a resistive memory, including: fabricating a bottom electrode over a substrate; partially oxidizing a metal of the bottom electrode through dry-oxygen oxidation or wet-oxygen oxidation to form a metal oxide with a thickness of 3 nm to 50 nm as a resistive material layer; finally fabricating a top electrode over the resistive material layer. The present invention omits a step of depositing a resistive material layer in a conventional method, so as to greatly reduce the process complexity. Meanwhile, a self alignment between the resistive material layer and the bottom electrode can be realized. A full isolation between devices may be ensured so as to obviate the parasite effects occurred in the conventional process methods. Meanwhile, the actual area and designed area of the device are ensured to be consistent.
    Type: Application
    Filed: April 16, 2012
    Publication date: August 22, 2013
    Applicant: PEKING UNIVERSITY
    Inventors: Ru Huang, Shenghu Tan, Lijie Zhang, Yue Pan, Yinglong Huang, Gengyu Yang, Yu Tang, Jun Mao, Yimao Cai
  • Patent number: 8513639
    Abstract: The present invention discloses a resistive-switching memory and the fabrication method thereof. The resistive-switching memory comprises a substrate, a top electrode, a bottom electrode, and a resistive-switching material interposed between the top and bottom electrodes, wherein the central portion of the bottom electrode protrudes upwards to form a peak shape, and the top electrode is in a plate shape. The peak structure of the bottom electrode reduces power consumption of the device. The fabrication method thereof comprises forming peak structures on the surface of the substrate by means of corrosion, and then growing bottom electrodes thereon to form bottom electrodes having peak shapes, and depositing resistive-switching material and top electrodes. The entire fabrication process is simple, and high integration degree of the device can be achieved.
    Type: Grant
    Filed: April 12, 2011
    Date of Patent: August 20, 2013
    Assignee: Peking University
    Inventors: Yimao Cai, Ru Huang, Yangyuan Wang, Yinglong Huang
  • Publication number: 20130099300
    Abstract: The present invention discloses a floating gate structure of a flash memory device and a method for fabricating the same, which relates to a nonvolatile memory in a manufacturing technology of an ultra-large-scaled integrated circuit. In the invention, by modifying a manufacturing of a floating gate in the a standard process for the flash memory, that is, by adding three steps of deposition, two steps of etching and one step of CMP, an I-shaped floating gate is formed. In addition to these steps, all the other steps are the same as those of the standard process for the flash memory process. By the invention, a coupling ratio may be improved effectively and a crosstalk between adjacent devices may be lowered, without adding additional photomasks and barely increasing a process complexity, which are very important to improve programming speed and reliability.
    Type: Application
    Filed: November 30, 2011
    Publication date: April 25, 2013
    Applicant: PEKING UNIVERSITY
    Inventors: Yimao Cai, Song Mei, Ru Huang
  • Publication number: 20130069031
    Abstract: The present invention discloses a multilevel resistive memory having large storage capacity, which belongs to a field of a fabrication technology of a resistive memory. The resistive memory includes an top electrode and a bottom electrode, and a combination of a plurality of switching layers and defective layers interposed between the top electrode and the bottom electrode, wherein, the top electrode and the bottom electrode are respectively contacted with a switching layer (a film such as Ta2O5, TiO2, HfO2), and the defective layers (metal film such as Ti, Au, Ag) are interposed between the switching layers. By using the present invention, a storage capacity of a resistive memory can be increased.
    Type: Application
    Filed: February 8, 2012
    Publication date: March 21, 2013
    Applicant: PEKING UNIVERSITY NO. 5 YIHEYUAN ROAD HAIDIAN DISTRICT
    Inventors: Ru Huang, Gengyu Yang, Yimao Cai, Yu Tang, Lijie Zhang, Yue Pan, Shenghu Tan, Yinglong Huang
  • Publication number: 20120261740
    Abstract: The present invention discloses a flash memory and a method for fabricating the same, and relates to the technical field of the semiconductor memory. The flash memory includes a buried oxygen layer on which a source terminal, a channel, and a drain terminal are disposed, wherein the channel is between the source terminal and the drain terminal, and a tunneling oxide layer, a polysilicon floating gate, a blocking oxide layer, and a polysilicon control gate are sequentially disposed on the channel, and a thin silicon nitride layer is disposed between the source terminal and the channel.
    Type: Application
    Filed: October 14, 2011
    Publication date: October 18, 2012
    Applicant: PEKING UNIVERSITY
    Inventors: Yimao Cai, Ru Huang, Shiqiang Qin, Poren Tang, Shenghu Tan
  • Publication number: 20120243313
    Abstract: The invention provides a flash memory array structure and a method for programming the same, which relates to a technical field of nonvolatile memories in ultra large scale integrated circuit fabrication technology. The flash memory array of the present invention includes memory cells, word lines and bit lines connected to the memory cells, wherein the word lines connected to control gates of the memory cells and the bit lines connected to drain terminals of the memory cells are not perpendicular to each other but cross each other at an angle; the control gates of two memory cells adjacent to each other along the channel direction between every two bit lines are controlled by two word lines, respectively, drain terminals thereof are controlled by two bit lines, respectively, and source terminals thereof are shared. The present invention also provides a method for programming the flash memory array structure, which can realize a programming with low power consumption.
    Type: Application
    Filed: April 21, 2011
    Publication date: September 27, 2012
    Inventors: Yimao Cai, Ru Huang, Poren Tang, Shiqiang Qin
  • Publication number: 20120241712
    Abstract: The present invention discloses a resistive-switching memory and the fabrication method thereof. The resistive-switching memory comprises a substrate, a top electrode, a bottom electrode, and a resistive-switching material interposed between the top and bottom electrodes, wherein the central portion of the bottom electrode protrudes upwards to form a peak shape, and the top electrode is in a plate shape. The peak structure of the bottom electrode reduces power consumption of the device. The fabrication method thereof comprises forming peak structures on the surface of the substrate by means of corrosion, and then growing bottom electrodes thereon to form bottom electrodes having peak shapes, and depositing resistive-switching material and top electrodes. The entire fabrication process is simple, and high integration degree of the device can be achieved.
    Type: Application
    Filed: April 12, 2011
    Publication date: September 27, 2012
    Inventors: Yimao Cai, Ru Huang, Yangyuan Wang, Yinglong Huang
  • Publication number: 20120188821
    Abstract: The present invention discloses a method for achieving four-bit storage by using a flash memory having a splitting trench gate. The flash memory with the splitting trench gate is disclosed in a Chinese patent No. 200710105964.2. At one side that each of two trenches is contacted with a channel, a programming for electrons is achieved by using a channel hot electron injection method; and at the other side that each of the two trenches is contacted with a source or a drain, a programming for electrons is achieved by using an FN injection method, so that a function of a four-bit storage of the device is achieved by changing a programming mode. Thus, a performance of the device is improved while a storage density is greatly increased.
    Type: Application
    Filed: October 14, 2011
    Publication date: July 26, 2012
    Inventors: Yimao Cai, Ru Huang, Shiqiang Qin, Poren Tang, Yu Tang, Shenghu Tan, Xin Huang, Yue Pan
  • Publication number: 20120113726
    Abstract: The present invention discloses a flash memory and the fabrication method and the operation method for the same. The flash memory comprises two memory cells of vertical channels, wherein a lightly-doped N type (or P type) silicon is used as a substrate; a P+ region (or an N+ region) is provided on each of the both ends of the silicon surface, and two channel regions perpendicular to the surface are provided therebetween; an N+ region (or a P+ region) shared by two channels is provided over the channels; a tunneling oxide layer, a polysilicon floating gate, a block oxide layer and a polysilicon control gate are provided sequentially on the outer sides of each channel from inside to outside; and the polysilicon floating gate and the polysilicon control gate are isolated from the P+ region by a sidewall oxide layer. The whole device is a two-bit TFET type flash memory with vertical channels which has better compatibility with prior-art standard CMOS process.
    Type: Application
    Filed: March 7, 2011
    Publication date: May 10, 2012
    Applicant: PEKING UNIVERSITY
    Inventors: Ru Huang, Yimao Cai, Shiqiang Qin, Qianqian Huang, Poren Tang, Yu Tang, Gengyu Yang
  • Publication number: 20120099381
    Abstract: The present invention discloses an embedded non-volatile memory cell, an operation method and a memory array thereof. The method includes using a gate of a selection transistor as a floating gate of a memory, and using a source electrode and a drain electrode of the selection transistor as a source electrode and a drain electrode of the memory; and then changing a threshold of the device by varying the electrode voltages, thereby realizing a storage and change of information. The invention has advantages of a small area, a low operating voltage, high operating speed and high reliability.
    Type: Application
    Filed: May 19, 2011
    Publication date: April 26, 2012
    Applicant: PEKING UNIVERSITY
    Inventors: Yimao Cai, Poren Tang, Ru Huang, Xiaoyan Xu
  • Publication number: 20120061637
    Abstract: The present invention relates to a field of nonvolatile memory technology in ULSI circuits manufacturing technology and discloses a 3D-structured resistive-switching memory array and a method for fabricating the same.
    Type: Application
    Filed: April 1, 2011
    Publication date: March 15, 2012
    Inventors: Yimao Cai, Ru Huang, Shiqiang Qin, Poren Tang, LIjie Zhang, Yu Tang