Patents by Inventor Yeeheng Lee

Yeeheng 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: 20150357406
    Abstract: This invention discloses a method for manufacturing a semiconductor power device on a semiconductor substrate supporting a . drift region composed of an epitaxial layer. The method includes a first step of growing a first epitaxial layer followed by forming a first hard mask layer on top of the epitaxial layer; a second step of applying a first implant mask to open a plurality of implant windows and applying a second implant mask for blocking some of the implant windows to implant a plurality of dopant regions of alternating conductivity types adjacent to each other in the first epitaxial layer; and a third step of repeating the first step and the second step by applying the same first and second implant masks to form a plurality of epitaxial layers, each of which is implanted with the dopant regions of the alternating conductivity types.
    Type: Application
    Filed: June 8, 2014
    Publication date: December 10, 2015
    Inventors: Lingpeng Guan, Madhur Bobde, Anup Bhalla, Yeeheng Lee, John Chen, Moses Ho
  • Publication number: 20150340363
    Abstract: A high density trench-gated MOSFET array and method are disclosed. It comprises semiconductor substrate partitioned into MOSFET array area and gate pickup area; epitaxial region, body region and source region; numerous precisely spaced active nitride-capped trench gate stacks (ANCTGS) embedded till the epitaxial region. Each ANCTGS comprises a stack of polysilicon trench gate with gate oxide shell and silicon nitride cap covering top of polysilicon trench gate and laterally registered to gate oxide shell. The ANCTGS forms, together with the source, body, epitaxial region, a MOSFET device in the MOSFET array area. Over MOSFET array area and gate pickup area, a patterned dielectric region atop the MOSFET array and a patterned metal layer atop the patterned dielectric region. Thus, the patterned metal layer forms, with the MOSFET array and the gate pickup area, self-aligned source and body contacts through the inter-ANCTGS separations.
    Type: Application
    Filed: August 6, 2015
    Publication date: November 26, 2015
    Applicant: ALPHA AND OMEGA SEMICONDUCTOR INCORPORATED
    Inventors: Yeeheng - Lee, Jongoh Kim, Hong Chang
  • Patent number: 9196701
    Abstract: A semiconductor substrate comprises epitaxial region, body region and source region; an array of interdigitated active nitride-capped trench gate stacks (ANCTGS) and self-guided contact enhancement plugs (SGCEP) disposed above the semiconductor substrate and partially embedded into the source region, the body region and the epitaxial region forming the trench-gated MOSFET array.
    Type: Grant
    Filed: March 5, 2014
    Date of Patent: November 24, 2015
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventors: Yeeheng Lee, Jongoh Kim, Hong Chang
  • Publication number: 20150333174
    Abstract: A semiconductor device may have an active device region containing a plurality of active devices and a termination structure that surrounds the active device region. The termination structure includes a first conductive region that surrounds the active device region, an insulator region that surrounds the first conductive region, and a second conductive region that surrounds the first conductive region and the insulator region. The active device region and termination structure are formed into a semiconductor material of a first conductivity type. The first conductive region is electrically connected to a gate metal and the second conductive region is connected to a drain metal.
    Type: Application
    Filed: July 23, 2015
    Publication date: November 19, 2015
    Inventors: Yeeheng Lee, Madhur Bobde, Daniel Calafut, Hamza Yilmaz, Xiaobin Wang, Ji Pan, Hong Chang, Jongoh Kim
  • Patent number: 9190512
    Abstract: Aspects of the present disclosure describe a high density trench-based power MOSFET with self-aligned source contacts. The source contacts are self-aligned with a first insulative spacer and a second insulative spacer, wherein the first spacer is resistant to an etching process that will selectively remove the material the second spacer is made from. Additionally, the active devices may have a two-step gate oxide, wherein a lower portion of the gate oxide has a thickness T2 that is larger than the thickness T1 of an upper portion of the gate oxide. It is emphasized that this abstract is provided to comply with rules requiring an abstract that will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims.
    Type: Grant
    Filed: January 27, 2015
    Date of Patent: November 17, 2015
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventors: Yeeheng Lee, Hong Chang, Jongoh Kim, Sik Lui, Hamza Yilmaz, Madhur Bobde, Daniel Calafut, John Chen
  • Patent number: 9190478
    Abstract: A method for forming a dual oxide thickness trench gate structure for a power MOSFET includes providing a semiconductor substrate; forming a first trench on a top surface of the substrate; forming a first oxide layer in the first trench where the first oxide layer has a first depth from the bottom of the first trench; forming a dielectric spacer along the sidewall of the first trench and on the first oxide layer; etching the first oxide layer exposed by the dielectric spacer to a second depth from the bottom of the first trench using the dielectric spacer as a mask where the second depth is lower than the first depth; removing the dielectric spacer; and forming a second oxide layer along the sidewall of the first trench above the first oxide layer where the second oxide layer has a thickness thinner than the thickness of the first oxide layer.
    Type: Grant
    Filed: December 22, 2013
    Date of Patent: November 17, 2015
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventors: Daniel Calafut, Madhur Bobde, Yeeheng Lee, Hong Chang
  • Publication number: 20150311295
    Abstract: Embodiments of the present disclosure provide a contact structure in a split-gate trench transistor device for electrically connecting the top electrode to the bottom electrode inside the trench. The transistor device comprises a semiconductor substrate and one or more trenches formed in the semiconductor substrate. The trenches are lined with insulating materials along the sidewalls inside the trenches. Each trench has a bottom electrode in lower portions of the trench and a top electrode in its upper portions. The bottom electrode and the top electrode are separated by an insulating material. A contact structure filled with conductive materials is formed in each trench in an area outside of an active region of the device to connect the top electrode and the bottom electrode. It is emphasized that this abstract is provided to comply with rules requiring an abstract that will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure.
    Type: Application
    Filed: April 23, 2014
    Publication date: October 29, 2015
    Applicant: Alpha and Omega Semiconductor Incorporated
    Inventors: Yeeheng Lee, Sik Lui, Jongoh Kim, Hong Chang, Madhur Bobde, Lingpeng Guan, Hamza Yilmaz
  • Publication number: 20150270383
    Abstract: A semiconductor device having a plurality of transistors includes a termination area that features a transistor with an asymmetric gate.
    Type: Application
    Filed: March 24, 2014
    Publication date: September 24, 2015
    Applicant: ALPHA & OMEGA SEMICONDUCTOR INCORPORATED
    Inventors: Yeeheng Lee, Yongping Dong, Xiaobin Wang
  • Patent number: 9136380
    Abstract: Aspects of the present disclosure describe a high density trench-based power MOSFETs with self-aligned source contacts and methods for making such devices. The source contacts are self-aligned with spacers that are formed along the sidewall of the gate caps. Additionally, the active devices may have a two-step gate oxide. A lower portion may have a thickness that is larger than the thickness of an upper portion of the gate oxide. The two-step gate oxide combined with the self-aligned source contacts allow for the production of devices with a pitch in the deep sub-micron level. It is emphasized that this abstract is provided to comply with rules requiring an abstract that will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims.
    Type: Grant
    Filed: July 11, 2014
    Date of Patent: September 15, 2015
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventors: Hamza Yilmaz, Madhur Bobde, Hong Chang, Yeeheng Lee, Daniel Calafut, Jongoh Kim, Sik Lui, John Chen
  • Patent number: 9136377
    Abstract: A high density trench-gated MOSFET array and method are disclosed. It comprises semiconductor substrate partitioned into MOSFET array area and gate pickup area; epitaxial region, body region and source region; numerous precisely spaced active nitride-capped trench gate stacks (ANCTGS) embedded till the epitaxial region. Each ANCTGS comprises a stack of polysilicon trench gate with gate oxide shell and silicon nitride cap covering top of polysilicon trench gate and laterally registered to gate oxide shell. The ANCTGS forms, together with the source, body, epitaxial region, a MOSFET device in the MOSFET array area. Over MOSFET array area and gate pickup area, a patterned dielectric region atop the MOSFET array and a patterned metal layer atop the patterned dielectric region. Thus, the patterned metal layer forms, with the MOSFET array and the gate pickup area, self-aligned source and body contacts through the inter-ANCTGS separations.
    Type: Grant
    Filed: March 11, 2013
    Date of Patent: September 15, 2015
    Assignee: Alpha & Omega Semiconductor, Inc.
    Inventors: Yeeheng Lee, Jongoh Kim, Hong Chang
  • Publication number: 20150255565
    Abstract: A semiconductor substrate comprises epitaxial region, body region and source region; an array of interdigitated active nitride-capped trench gate stacks (ANCTGS) and self-guided contact enhancement plugs (SGCEP) disposed above the semiconductor substrate and partially embedded into the source region, the body region and the epitaxial region forming the trench-gated MOSFET array.
    Type: Application
    Filed: March 5, 2014
    Publication date: September 10, 2015
    Inventors: Yeeheng Lee, Jongoh Kim, Hong Chang
  • Patent number: 9105494
    Abstract: Aspects of the present disclosure describe a termination structure for a power MOSFET device. A termination trench may be formed into a semiconductor material and may encircle an active area of the MOSFET. The termination trench may comprise a first and second portion of conductive material. The first and second portions of conductive material are electrically isolated from each other. It is emphasized that this abstract is provided to comply with rules requiring an abstract that will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims.
    Type: Grant
    Filed: February 25, 2013
    Date of Patent: August 11, 2015
    Assignee: Alpha and Omega Semiconductors, Incorporated
    Inventors: Yeeheng Lee, Madhur Bodbe, Daniel Calafut, Hamza Yilmaz, Xiaobin Wang, Ji Pan, Hong Chang, Jongoh Kim
  • Publication number: 20150221734
    Abstract: Semiconductor device fabrication method and devices are disclosed. The semiconductor power device is formed on a semiconductor substrate having a plurality of trench transistor cells each having a trench gate. Each of the trench gates having a thicker bottom oxide (TBO) formed by a REOX process on a polysilicon layer deposited on a bottom surface of the trenches.
    Type: Application
    Filed: February 4, 2014
    Publication date: August 6, 2015
    Inventors: Yeeheng Lee, Xiaobin Wang
  • Publication number: 20150179750
    Abstract: A method for forming a dual oxide thickness trench gate structure for a power MOSFET includes providing a semiconductor substrate; forming a first trench on a top surface of the substrate; forming a first oxide layer in the first trench where the first oxide layer has a first depth from the bottom of the first trench; forming a dielectric spacer along the sidewall of the first trench and on the first oxide layer; etching the first oxide layer exposed by the dielectric spacer to a second depth from the bottom of the first trench using the dielectric spacer as a mask where the second depth is lower than the first depth; removing the dielectric spacer; and forming a second oxide layer along the sidewall of the first trench above the first oxide layer where the second oxide layer has a thickness thinner than the thickness of the first oxide layer.
    Type: Application
    Filed: December 22, 2013
    Publication date: June 25, 2015
    Inventors: Daniel Calafut, Madhur Bobde, Yeeheng Lee, Hong Chang
  • Publication number: 20150145037
    Abstract: Aspects of the present disclosure describe a high density trench-based power MOSFET with self-aligned source contacts. The source contacts are self-aligned with a first insulative spacer and a second insulative spacer, wherein the first spacer is resistant to an etching process that will selectively remove the material the second spacer is made from. Additionally, the active devices may have a two-step gate oxide, wherein a lower portion of the gate oxide has a thickness T2 that is larger than the thickness T1 of an upper portion of the gate oxide. It is emphasized that this abstract is provided to comply with rules requiring an abstract that will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims.
    Type: Application
    Filed: January 27, 2015
    Publication date: May 28, 2015
    Inventors: Yeeheng Lee, Hong Chang, Jongoh Kim, Sik Lui, Hamza Yilmaz, Madhur Bobde, Daniel Calafut, John Chen
  • Publication number: 20150115333
    Abstract: This invention discloses configurations and methods to manufacture lateral power device including a super-junction structure with an avalanche clamp diode formed between the drain and the gate. The lateral super-junction structure reduces on-resistance, while the structural enhancements, including an avalanche clamping diode and an N buffer region, increase the breakdown voltage between substrate and drain and improve unclamped inductive switching (UIS) performance.
    Type: Application
    Filed: October 24, 2013
    Publication date: April 30, 2015
    Inventors: Madhur Bobde, Anup Bhalla, Hamza Yilmaz, Wilson Ma, Lingpeng Guan, Yeeheng Lee, John Chen
  • Patent number: 9000514
    Abstract: Semiconductor device fabrication method and devices are disclosed. A device may be fabricated by forming in a semiconductor layer; filling the trench with an insulating material; removing selected portions of the insulating material leaving a portion of the insulating material in a bottom portion of the trench; forming one or more spacers on one or more sidewalls of a remaining portion of the trench; anisotropically etching the insulating material in the bottom portion of the trench using the spacers as a mask to form a trench in the insulator; removing the spacers; and filling the trench in the insulator with a conductive material. Alternatively, an oxide-nitride-oxide (ONO) structure may be formed on a sidewall and at a bottom of the trench and one or more conductive structures may be formed in a portion of the trench not occupied by the ONO structure.
    Type: Grant
    Filed: July 27, 2012
    Date of Patent: April 7, 2015
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventors: Yeeheng Lee, Sung-Shan Tai, Hong Chang, John Chen
  • Patent number: 8969953
    Abstract: Self-aligned charge balanced semiconductor devices and methods for forming such devices are disclosed. One or more planar gates are formed over a semiconductor substrate of a first conductivity type. One or more deep trenches are etched in the semiconductor self-aligned to the planar gates. The trenches are filled with a semiconductor material of a second conductivity type such that the deep trenches are charge balanced with the adjacent regions of the semiconductor substrate Source and body regions are formed by implanting dopants onto the filled trenches. This process can form self-aligned charge balanced devices with a cell pitch less than 12 microns.
    Type: Grant
    Filed: August 26, 2013
    Date of Patent: March 3, 2015
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventors: John Chen, Yeeheng Lee, Lingpeng Guan, Moses Ho, Wilson Ma, Anup Bhalla, Hamza Yilmaz
  • Patent number: 8951867
    Abstract: Aspects of the present disclosure describe a high density trench-based power MOSFET with self-aligned source contacts. The source contacts are self-aligned with a first insulative spacer and a second insulative spacer, wherein the first spacer is resistant to an etching process that will selectively remove the material the second spacer is made from. Additionally, the active devices may have a two-step gate oxide, wherein a lower portion of the gate oxide has a thickness T2 that is larger than the thickness T1 of an upper portion of the gate oxide. It is emphasized that this abstract is provided to comply with rules requiring an abstract that will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims.
    Type: Grant
    Filed: December 21, 2012
    Date of Patent: February 10, 2015
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventors: Yeeheng Lee, Hong Chang, Jongoh Kim, Sik Lui, Hamza Yilmaz, Madhur Bobde, Daniel Calafut, John Chen
  • Publication number: 20140374824
    Abstract: Aspects of the present disclosure describe a Schottky structure with two trenches formed in a semiconductor material. The trenches are spaced apart from each other by a mesa. Each trench may have first and second conductive portions lining the first and second sidewalls. The first and second portions of conductive material are electrically isolated from each other in each trench. The Schottky contact may be formed at any location between the outermost conductive portions. The Schottky structure may be formed in the active area or the termination area of a device die. It is emphasized that this abstract is provided to comply with rules requiring an abstract that will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims.
    Type: Application
    Filed: June 25, 2013
    Publication date: December 25, 2014
    Inventors: Daniel Calafut, Yeeheng Lee