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).

  • Publication number: 20230058216
    Abstract: A self-aligning preparation method for a drain underlap region in a tunnel field effect transistor: designing asymmetric side wall structures on two sides of the gate of a tunnel field effect transistor, the side of the gate closest to the source region being a thin side wall and the side of the gate closest to the drain region being a thick side wall; and using the source region thin side wall as a hard mask for implantation of the source region of the transistor and the drain region thick side wall as a hard mask for implantation of the drain region of the transistor. The present method effectively uses the thin side walls and thick side walls existing in standard CMOS processes to suppress the ambipolar effect of the tunnel field effect transistor without introducing special materials and special processes, and also optimizes the device variation characteristics.
    Type: Application
    Filed: November 30, 2020
    Publication date: February 23, 2023
    Inventors: Qianqian Huang, Yiqing Li, Kaifeng Wang, Menghuan Yang, Zhixuan Wang, Le Ye, Yimao Cai, Ru Huang
  • Patent number: 9525133
    Abstract: Disclosed is a resistive random access memory, comprising a substrate, an insulating layer, a bottom electrode, a resistive material film, and a top electrode in an order from bottom to top, wherein the resistive material film is a four-layer structure composed of a same metal oxide; and the four layers in the four-layer structure from bottom to top have resistance values which are increased one after another by more than 10 times, oxygen concentrations which are increased one after another and thickness which are decreased one after another. The present invention may achieve complete formation-rupture of oxygen vacancy conductive filaments (CF) in each layer by dividing the resistive material film of the same metal oxide into four layers according to the different oxygen concentrations, so as to control accurately the resistance values, so that 2-bit storage with high uniformity is achieved.
    Type: Grant
    Filed: March 31, 2014
    Date of Patent: December 20, 2016
    Assignee: PEKING UNIVERSITY
    Inventors: Ru Huang, Muxi Yu, Yimao Cai, Zhenxing Zhang, Qiang Li, Ming Li
  • Patent number: 9431620
    Abstract: The present invention discloses an organic resistive random access memory and a preparation method thereof. The memory uses silicon as a substrate, and has a MIM capacitor structure having a vertical memory unit, where the MIM structure has a top electrode of Al, a bottom electrode of ITO, and an middle functional layer of parylene, wherein, a parylene layer as the functional layer is formed by performing deposition multiple times, where the deposition of Al2O3 is performed once by ALD between each two deposition of parylene. A critical region which is in favor of forming a conductive channel could be formed by controlling the deposition area of Al2O3, and further control the electrical characteristics of the memory. Through the present invention, the cycle-to-cycle and device-to-device uniformity could be effectively improved, without changing the basic structure of the memory.
    Type: Grant
    Filed: September 30, 2013
    Date of Patent: August 30, 2016
    Assignee: Peking University
    Inventors: Yimao Cai, Yefan Liu, Wenliang Bai, Zongwei Wang, Yichen Fang, Ru Huang
  • Publication number: 20160240778
    Abstract: Disclosed are a multi-value nonvolatile organic resistive random access memory and a method for preparing the same. The resistive random access memory comprises a top electrode, a bottom electrode and a middle functional layer located between the top electrode and the bottom electrode, the middle functional layer is at least two layers of parylene. The method comprises the steps of: growing material for the bottom electrode using physical vapor deposition method on a substrate; growing sequentially multiple layers of parylene on the bottom electrode by polymer chemical vapor deposition; defining the via for leading out the bottom electrode by lithography and etching; growing material for the top electrode on the parylene materials by using physical vapor deposition process, defining the top electrode material by lithography and lift-off, and leading out the bottom electrode.
    Type: Application
    Filed: March 31, 2014
    Publication date: August 18, 2016
    Inventors: Yimao Cai, Yefan Liu, Yichen Fang, Zongwei Wang, Qiang Li, Muxi Yu, Yue Pan, Ru Huang
  • Publication number: 20160225987
    Abstract: Disclosed is a resistive random access memory, comprising a substrate, an insulating layer, a bottom electrode, a resistive material film, and a top electrode in an order from bottom to top, wherein the resistive material film is a four-layer structure composed of a same metal oxide; and the four layers in the four-layer structure from bottom to top have resistance values which are increased one after another by more than 10 times, oxygen concentrations which are increased one after another and thickness which are decreased one after another. The present invention may achieve complete formation-rupture of oxygen vacancy conductive filaments (CF) in each layer by dividing the resistive material film of the same metal oxide into four layers according to the different oxygen concentrations, so as to control accurately the resistance values, so that 2-bit storage with high uniformity is achieved.
    Type: Application
    Filed: March 31, 2014
    Publication date: August 4, 2016
    Inventors: Ru HUANG, Muxi YU, Yimao CAI, Zhenxing ZHANG, Qiang LI, Ming LI
  • Patent number: 9379322
    Abstract: The present invention relates to a highly reliable nonvolatile memory and a manufacturing method thereof. The nonvolatile memory comprises top electrodes, bottom electrodes and a resistive material layer disposed therebetween, wherein the top electrodes are positioned on top in the memory; the bottom electrodes are positioned on a substrate; metal oxide for forming the resistive material layer is doped with metal; and a metal oxygen storage layer is further disposed between the top electrodes and the resistive material layer. The manufacturing method adopts a method in which a doping method and a double-layer forming method are combined, so that the highly reliable and highly uniform resistive random access memory can be fabricated and accordingly the performance of the memory can be increased.
    Type: Grant
    Filed: September 30, 2013
    Date of Patent: June 28, 2016
    Assignee: Peking University
    Inventors: Ru Huang, Muxi Yu, Yimao Cai, Wenliang Bai, Yinglong Huang
  • Publication number: 20160110644
    Abstract: The present invention discloses a time correlation learning neuron circuit based on a resistive memristor and an implementation method thereof. The present invention utilizes switching characteristics of the resistive memristor. When two terminals of the resistive memristor are selected synchronously by two excitation signals, the voltage drop between these two terminals will change the resistance value of memristor, thereby achieving the on-off of a synapse connection and achieving the correction of the two excitation signals. Meanwhile the device also has a memory characteristic. Also, the previous excitation signal can be repeated. That is, the purpose of learning is achieved. Since the resistive memristor has a simple structure and a high degree of integration, it can achieve large-scale physical synapse connection in order to achieve more complex learning and even logic functions. The present invention has a good application prospect in a neuron cell computation.
    Type: Application
    Filed: September 30, 2013
    Publication date: April 21, 2016
    Inventors: Ru Huang, Yaokai Zhang, Yimao Cai, Fan Yang, Yue Pan, Zongwei Wang, Yichen Fang
  • Patent number: 9281476
    Abstract: Embodiments of the present invention disclose a resistive memory and a method for fabricating the same. The resistive memory comprises a bottom electrode, a resistive layer and a top electrode. The resistive layer is located over the bottom electrode. The top electrode is located over the resistive layer. A conductive protrusion is provided on the bottom electrode. The conductive protrusion is embedded in the resistive layer, and has a top width smaller than a bottom width. Embodiments of the present invention further disclose a method for fabricating a resistive memory. According to the resistive memory and the method for fabricating the same provided by the embodiments of the present invention, by means of providing the conductive protrusion on the bottom electrode, a “lightning rod” effect may be occurred so that an electric field in the resistive layer is intensively distributed near the conductive protrusion.
    Type: Grant
    Filed: July 8, 2013
    Date of Patent: March 8, 2016
    Assignee: Peking University
    Inventors: Yimao Cai, Shihui Yin, Ru Huang, Yichen Fang
  • Publication number: 20160049604
    Abstract: The present invention discloses an organic resistive random access memory and a preparation method thereof. The memory uses silicon as a substrate, and has a MIM capacitor structure having a vertical memory unit, where the MIM structure has a top electrode of Al, a bottom electrode of ITO, and an middle functional layer of parylene, wherein, a parylene layer as the functional layer is formed by performing deposition multiple times, where the deposition of Al2O3 is performed once by ALD between each two deposition of parylene. A critical region which is in favor of forming a conductive channel could be formed by controlling the deposition area of Al2O3, and further control the electrical characteristics of the memory. Through the present invention, the cycle-to-cycle and device-to-device uniformity could be effectively improved, without changing the basic structure of the memory.
    Type: Application
    Filed: September 30, 2013
    Publication date: February 18, 2016
    Inventors: Yimao Cai, Yefan Liu, Wenliang Bai, Zongwei Wang, Yichen Fang, Ru Huang
  • Patent number: 9214629
    Abstract: A resistive memory having a leakage inhibiting characteristic and a method for fabricating the same, which can suppress a sneak current in a large scaled crossing array of a RRAM. A memory cell forming the resistive memory comprises a lower electrode, a first semiconductor-type oxide layer, a resistive material layer, a second semiconductor-type oxide layer and an upper electrode which are sequentially stacked. Each of the semiconductor-type oxide layers may be a semiconductor-type metal oxide or a semiconductor-type non-metal oxide. The sneak current may be effectively reduced by means of a Schottky barrier formed between the semiconductor-type oxide layer and the metal electrode, the fabrication process is easy to be implemented, and a high device integration degree can be achieved.
    Type: Grant
    Filed: April 26, 2013
    Date of Patent: December 15, 2015
    Assignee: Peking University
    Inventors: Ru Huang, Yinglong Huang, Yimao Cai, Yangyuan Wang, Muxi Yu
  • Publication number: 20150349253
    Abstract: The present invention relates to a highly reliable nonvolatile memory and a manufacturing method thereof. The nonvolatile memory comprises top electrodes, bottom electrodes and a resistive material layer disposed therebetween, wherein the top electrodes are positioned on top in the memory; the bottom electrodes are positioned on a substrate; metal oxide for forming the resistive material layer is doped with metal; and a metal oxygen storage layer is further disposed between the top electrodes and the resistive material layer. The manufacturing method adopts a method in which a doping method and a double-layer forming method are combined, so that the highly reliable and highly uniform resistive random access memory can be fabricated and accordingly the performance of the memory can be increased.
    Type: Application
    Filed: September 30, 2013
    Publication date: December 3, 2015
    Inventors: Ru Huang, Muxi Yu, Yimao Cai, Wenliang Bai, Yinglong Huang
  • Patent number: 9142768
    Abstract: Systems and methods are disclosed involving a resistive memory with a small electrode, relating to the field of semiconductor resistive memory in ULSI. An illustrative resistive memory may include an Al electrode layer, a SiO2 layer, a Si layer, a resistive material layer and a lower electrode layer in sequence, wherein the Al electrode layer and the resistive material layer are electrically connected through one or more conductive channel and the conductive channel is formed by penetrating Al material into the Si layer via defects in the SiO2 layer and dissolving Si material into the Al material. Methods may include forming a lower electrode layer, a resistive layer, a Si layer and a SiO2 layer over a substrate; fabricating a Al electrode layer over the SiO2 layer; and performing an anneal process to the resultant structure. Consistent with innovations herein, a small electrode may be obtained via a conventional process.
    Type: Grant
    Filed: May 2, 2012
    Date of Patent: September 22, 2015
    Assignee: Peking University
    Inventors: Yimao Cai, Jun Mao, Ru Huang, Shenghu Tan, Yinglong Huang, Yue Pan
  • Publication number: 20150144861
    Abstract: Embodiments of the present invention disclose a resistive memory and a method for fabricating the same. The resistive memory comprises a bottom electrode, a resistive layer and a top electrode. The resistive layer is located over the bottom electrode. The top electrode is located over the resistive layer. A conductive protrusion is provided on the bottom electrode. The conductive protrusion is embedded in the resistive layer, and has a top width smaller than a bottom width. Embodiments of the present invention further disclose a method for fabricating a resistive memory. According to the resistive memory and the method for fabricating the same provided by the embodiments of the present invention, by means of providing the conductive protrusion on the bottom electrode, a “lightning rod” effect may be occurred so that an electric field in the resistive layer is intensively distributed near the conductive protrusion.
    Type: Application
    Filed: July 8, 2013
    Publication date: May 28, 2015
    Inventors: Yimao Cai, Shihui Yin, Ru Huang, Yichen Fang
  • Patent number: 8995165
    Abstract: The present invention discloses a resistive memory cell, including a unipolar type RRAM and a MOS transistor as a selection transistor serially connected to the unipolar type RRAM, wherein the MOS transistor is fabricated over a partial depletion SOI substrate and provides a large current for program and erase of the RRAM by using an intrinsic floating effect of the SOI substrate. The present invention utilizes a floating effect of a SOI device, in which under the same width/length ratio, a MOS transistor over a SOI substrate can provide larger source/drain current than a MOS transistor over a bulk silicon, so that the area occupied by the selection transistor is reduced, which is advantageous to the integration of the RRAM array.
    Type: Grant
    Filed: February 22, 2012
    Date of Patent: March 31, 2015
    Assignee: Peking University
    Inventors: Yimao Cai, Zhenni Wan, Ru Huang
  • Publication number: 20150041750
    Abstract: An embodiment of the present invention provides a resistive memory device and a method for fabricating the same. The resistive memory device includes a substrate and a plurality of memory cells spaced with each other over the substrate, each memory cell including a lower electrode, a resistive layer and an upper electrode, wherein the lower electrode is disposed over the substrate, the resistive layer is disposed over the lower electrode and the upper electrode is disposed over the resistive layer, and the resistive layer includes a resistive material portion and at least one doped resistive portion doped with an element for adjusting a resistance state.
    Type: Application
    Filed: October 11, 2012
    Publication date: February 12, 2015
    Inventors: Yimao Cai, Jun Mao, Huiwei Wu
  • Patent number: 8942036
    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: Grant
    Filed: October 14, 2011
    Date of Patent: January 27, 2015
    Assignee: Peking University
    Inventors: Yimao Cai, Ru Huang, Shiqiang Qin, Poren Tang, Yu Tang, Shenghu Tan, Xin Huang, Yue Pan
  • Publication number: 20150021539
    Abstract: Systems and methods are disclosed involving a resistive memory with a small electrode, relating to the field of semiconductor resistive memory in ULSI. An illustrative resistive memory may include an Al electrode layer, a SiO2 layer, a Si layer, a resistive material layer and a lower electrode layer in sequence, wherein the Al electrode layer and the resistive material layer are electrically connected through one or more conductive channel and the conductive channel is formed by penetrating Al material into the Si layer via defects in the SiO2 layer and dissolving Si material into the Al material. Methods may include forming a lower electrode layer, a resistive layer, a Si layer and a SiO2 layer over a substrate; fabricating a Al electrode layer over the SiO2 layer; and performing an anneal process to the resultant structure. Consistent with innovations herein, a small electrode may be obtained via a conventional process.
    Type: Application
    Filed: May 2, 2012
    Publication date: January 22, 2015
    Inventors: Yimao Cai, Jun Mao, Ru Huang, Shenghu Tan, Yinglong Huang, Yue Pan
  • Publication number: 20140306173
    Abstract: A resistive memory having a leakage inhibiting characteristic and a method for fabricating the same, which can suppress a sneak current in a large scaled crossing array of a RRAM. A memory cell forming the resistive memory comprises a lower electrode, a first semiconductor-type oxide layer, a resistive material layer, a second semiconductor-type oxide layer and an upper electrode which are sequentially stacked. Each of the semiconductor-type oxide layers may be a semiconductor-type metal oxide or a semiconductor-type non-metal oxide. The sneak current may be effectively reduced by means of a Schottky barrier formed between the semiconductor-type oxide layer and the metal electrode, the fabrication process is easy to be implemented, and a high device integration degree can be achieved.
    Type: Application
    Filed: April 26, 2013
    Publication date: October 16, 2014
    Inventors: Ru Huang, Yinglong Huang, Yimao Cai, Yangyuan Wang, Muxi Yu
  • Publication number: 20140268988
    Abstract: The present invention discloses a resistive memory cell, including a unipolar type RRAM and a MOS transistor as a selection transistor serially connected to the unipolar type RRAM, wherein the MOS transistor is fabricated over a partial depletion SOI substrate and provides a large current for program and erase of the RRAM by using an intrinsic floating effect of the SOI substrate. The present invention utilizes a floating effect of a SOI device, in which under the same width/length ratio, a MOS transistor over a SOI substrate can provide larger source/drain current than a MOS transistor over a bulk silicon, so that the area occupied by the selection transistor is reduced, which is advantageous to the integration of the RRAM array.
    Type: Application
    Filed: February 22, 2012
    Publication date: September 18, 2014
    Applicant: Peking University
    Inventors: Yimao Cai, Zhenni Wan, Ru Huang
  • Publication number: 20140145139
    Abstract: The present invention discloses a transparent flexible resistive memory and a fabrication method thereof. The transparent flexible resistive memory includes a transparent flexible substrate, a memory unit with a MIM capacitor structure over the substrate, wherein a bottom electrode and a top electrode of the memory unit are transparent and flexible, and an intermediate resistive layer is a transparent flexible film of poly(p-xylylene). Poly(p-xylylene) has excellent resistive characteristics. In the device, the substrate, the electrodes and the intermediate resistive layer are all formed of transparent flexible material so that a completely transparent flexible resistive memory which can be used in a transparent flexible electronic system is obtained.
    Type: Application
    Filed: February 22, 2012
    Publication date: May 29, 2014
    Inventors: Ru Huang, Yu Tang, Yimao Cai, Lijie Zhang, Gengyu Yang, Shenghu Tan, Yue Pan, Poren Tang