Patents by Inventor William Schaff

William Schaff 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: 10516076
    Abstract: A dislocation filter for a semiconductor device has a buffer layer comprising a short-period superlattice (SPSL) layer. The SPSL layer has first sub-layers of a first material that alternate with second sub-layers of a second material, the first material and the second material being group III-N binary materials that are different from each other. Each of the first sub-layers and each of the second sub-layers has a sub-layer thickness less than or equal to 12 monolayers. The buffer layer also includes a third layer of a third material, the third material being a group III-N material. The SPSL forms a sandwich structure with the third layer. The buffer layer bends dislocations away from a growth direction of the buffer layer.
    Type: Grant
    Filed: February 1, 2018
    Date of Patent: December 24, 2019
    Assignee: Silanna UV Technologies Pte Ltd
    Inventors: Liam Anderson, William Lee, William Schaff, Johnny Cai Tang
  • Publication number: 20190237616
    Abstract: A dislocation filter for a semiconductor device has a buffer layer comprising a short-period superlattice (SPSL) layer. The SPSL layer has first sub-layers of a first material that alternate with second sub-layers of a second material, the first material and the second material being group III-N binary materials that are different from each other. Each of the first sub-layers and each of the second sub-layers has a sub-layer thickness less than or equal to 12 monolayers. The buffer layer also includes a third layer of a third material, the third material being a group III-N material. The SPSL forms a sandwich structure with the third layer. The buffer layer bends dislocations away from a growth direction of the buffer layer.
    Type: Application
    Filed: February 1, 2018
    Publication date: August 1, 2019
    Applicant: Silanna UV Technologies Pte Ltd
    Inventors: Liam Anderson, William Lee, William Schaff, Johnny Cai Tang
  • Publication number: 20050179047
    Abstract: A method of forming a highly doped layer of AlGaN, is practiced by first removing contaminants from a MBE machine. Wafers are then outgassed in the machine at very low pressures. A nitride is then formed on the wafer and an AlN layer is grown. The highly doped GaAlN layer is then formed having electron densities beyond 1×1020 cm?3 at Al mole fractions up to 65% are obtained. These levels of doping application of n-type bulk, and n/p tunnel injection to short wavelength UV emitters. Some applications include light emitting diodes having wavelengths between approximately 254 and 290 nm for use in fluorescent light bulbs, hazardous materials detection, water purification and other decontamination environments. Lasers formed using the highly doped layers are useful in high-density storage applications or telecommunications applications. In yet a further embodiment, a transistor is formed utilizing the highly doped layer as a channel.
    Type: Application
    Filed: March 17, 2005
    Publication date: August 18, 2005
    Inventors: William Schaff, Jeonghyun Hwang
  • Publication number: 20050179050
    Abstract: A wide bandgap semiconductor material is heavily doped to a degenerate level. Impurity densities approaching 1% of the volume of the semiconductor crystal are obtained to greatly increase conductivity. In one embodiment, a layer of AlGaN is formed on a wafer by first removing contaminants from a MBE machine. Wafers are then outgassed in the machine at very low pressures. A nitride is then formed on the wafer and an AIN layer is grown. The highly doped GaAlN layer is then formed having electron densities beyond 1×1020 cm?3 at Al mole fractions up to 65% are obtained.
    Type: Application
    Filed: March 16, 2005
    Publication date: August 18, 2005
    Inventors: William Schaff, Jeonghyun Hwang