Patents by Inventor UI Ho CHOI

UI Ho CHOI 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: 11978629
    Abstract: The present invention relates to a method of manufacturing an AlN-based transistor. An AlN-based high electron mobility transistor (HEMT) element according to the present invention may use an AlN buffer layer, and include an AlGaN composition change layer inserted into a GaN/AlN interface to remove or suppress a degree of generation of a two-dimensional hole gas (2DHG), thereby decreasing an influence of a coulomb drag on a two-dimensional electron gas (2DEG) layer and improving mobility of a two-dimensional electron gas (2DEG).
    Type: Grant
    Filed: November 27, 2019
    Date of Patent: May 7, 2024
    Assignee: KOREA POLYTECHNIC UNIVERSITY INDUSTRY ACADEMIC COOPERATION FOUNDATION
    Inventors: Ok Hyun Nam, Ui Ho Choi
  • Patent number: 11699587
    Abstract: The present invention relates to a method for manufacturing a diamond substrate, and more particularly, to a method of growing diamond after forming a structure of an air gap having a crystal correlation with a lower substrate by heat treatment of a photoresist pattern and an air gap forming film material on a substrate such as sapphire (Al2O3). Through such a method, a process is simplified and the cost is lowered when large-area/large-diameter single crystal diamond is heterogeneously grown, stress due to differences in a lattice constant and a coefficient of thermal expansion between the heterogeneous substrate and diamond is relieved, and an occurrence of defects or cracks is reduced even when a temperature drops, such that a high-quality single crystal diamond substrate may be manufactured and the diamond substrate may be easily self-separated from the heterogeneous substrate.
    Type: Grant
    Filed: November 27, 2019
    Date of Patent: July 11, 2023
    Assignee: KOREA POLYTECHNIC UNIVERSITY INDUSTRY ACADEMIC COOPERATION FOUNDATION
    Inventors: Ok Hyun Nam, Ui Ho Choi, Geun Ho Yoo
  • Publication number: 20220285154
    Abstract: The present invention relates to a method for manufacturing a diamond substrate, and more particularly, to a method of growing diamond after forming a structure of an air gap having a crystal correlation with a lower substrate by heat treatment of a photoresist pattern and an air gap forming film material on a substrate such as sapphire (Al2O3). Through such a method, a process is simplified and the cost is lowered when large-area/large-diameter single crystal diamond is heterogeneously grown, stress due to differences in a lattice constant and a coefficient of thermal expansion between the heterogeneous substrate and diamond is relieved, and an occurrence of defects or cracks is reduced even when a temperature drops, such that a high-quality single crystal diamond substrate may be manufactured and the diamond substrate may be easily self-separated from the heterogeneous substrate.
    Type: Application
    Filed: November 27, 2019
    Publication date: September 8, 2022
    Inventors: Ok Hyun NAM, Ui Ho CHOI, Geun Ho YOO
  • Publication number: 20220051888
    Abstract: The present invention relates to a method of manufacturing an AlN-based transistor. An AlN-based high electron mobility transistor (HEMT) element according to the present invention may use an AlN buffer layer, and include an AlGaN composition change layer inserted into a GaN/AlN interface to remove or suppress a degree of generation of a two-dimensional hole gas (2DHG), thereby decreasing an influence of a coulomb drag on a two-dimensional electron gas (2DEG) layer and improving mobility of a two-dimensional electron gas (2DEG).
    Type: Application
    Filed: November 27, 2019
    Publication date: February 17, 2022
    Inventors: Ok Hyun NAM, UI Ho CHOI