Patents by Inventor Changhua Chen

Changhua Chen 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: 20140241658
    Abstract: A device, such as a silicon modulator, in accordance with the present disclosure employs PN diodes without sacrificing the modulation depth, while achieving lower loss and better impedance matching to 50-Ohm drivers. In one embodiment, the device includes an input waveguide, an input optical splitter coupled to the input waveguide, first and second optical phase shifters coupled to the input optical splitter, an output optical splitter coupled to the first and second phase shifters, and an output waveguide coupled to the output optical splitter. The phase shifters are designed with variant capacitance per unit length.
    Type: Application
    Filed: February 21, 2014
    Publication date: August 28, 2014
    Applicant: SiFotonics Technologies Co., Ltd.
    Inventors: Changhua Chen, Dong Pan, Yanwu Zhang, Wang Chen, Pengfei Cai, Ching-yin Hong, Siying Liu
  • Publication number: 20120216281
    Abstract: A method and apparatus for resisting malicious code in a computing device. A software component corresponding to an operating system kernel is analyzed prior to executing the software component to detect the presence of one or more specific instructions such as malicious code, a change in mode permissions or instructions to modify or turn off security monitoring software, and taking a graduated action in response to the detection of one or more specific instructions. The graduated action taken is specified by a security policy (or policies) stored on the computing device. The analyzing may include off-line scanning of a particular code or portion of code for certain instructions, op codes, or patterns, and includes scanning in real-time as the kernel or kernel module is loading while the code being scanned is not yet executing (i.e., it is not yet “on-line”). Analysis of other code proceeds according to policies.
    Type: Application
    Filed: December 9, 2011
    Publication date: August 23, 2012
    Applicant: PCTEL Secure LLC
    Inventors: Eric Ridvan Uner, Benjamin James Leslie, Joshua Scott Matthews, Changhua Chen, Thomas Smigelski, Anthony Kobrinetz
  • Patent number: 7345323
    Abstract: P-type layers of a GaN based light-emitting device are optimized for formation of Ohmic contact with metal. In a first embodiment, a p-type GaN transition layer with a resistivity greater than or equal to about 7 ? cm is formed between a p-type conductivity layer and a metal contact. In a second embodiment, the p-type transition layer is any III-V semiconductor. In a third embodiment, the p-type transition layer is a superlattice. In a fourth embodiment, a single p-type layer of varying composition and varying concentration of dopant is formed.
    Type: Grant
    Filed: March 30, 2005
    Date of Patent: March 18, 2008
    Assignee: Philips Lumileds Lighting Company LLC
    Inventors: Werner K. Goetz, Michael D. Camras, Xiaoping Chen, legal representative, Gina L. Christenson, R. Scott Kern, Chihping Kuo, Paul Scott Martin, Daniel A. Steigerwald, Changhua Chen
  • Publication number: 20050167693
    Abstract: P-type layers of a GaN based light-emitting device are optimized for formation of Ohmic contact with metal. In a first embodiment, a p-type GaN transition layer with a resistivity greater than or equal to about 7 ? cm is formed between a p-type conductivity layer and a metal contact. In a second embodiment, the p-type transition layer is any III-V semiconductor. In a third embodiment, the p-type transition layer is a superlattice. In a fourth embodiment, a single p-type layer of varying composition and varying concentration of dopant is formed.
    Type: Application
    Filed: March 30, 2005
    Publication date: August 4, 2005
    Inventors: Werner Goetz, Michael Camras, Changhua Chen, Xiaoping Chen, Gina Christenson, R. Kern, Chihping Kuo, Paul Martin, Daniel Steigerwald
  • Patent number: 6914272
    Abstract: P-type layers of a GaN based light-emitting device are optimized for formation of Ohmic contact with metal. In a first embodiment, a p-type GaN transition layer with a resistivity greater than or equal to about 7 ?cm is formed between a p-type conductivity layer and a metal contact. In a second embodiment, the p-type transition layer is any III-V semiconductor. In a third embodiment, the p-type transition layer is a superlattice. In a fourth embodiment, a single p-type layer of varying composition and varying concentration of dopant is formed.
    Type: Grant
    Filed: November 24, 2003
    Date of Patent: July 5, 2005
    Assignee: Lumileds Lighting U.S., LLC
    Inventors: Werner K. Goetz, Michael D. Camras, Changhua Chen, Gina L. Christenson, R. Scott Kern, Chihping Kuo, Paul Scott Martin, Daniel A. Steigerwald
  • Patent number: 6888171
    Abstract: A semi-conductor light emitting diode includes closely spaced n and p electrodes formed on the same side of a substrate to form an LED with a small foot-print. A semi-transparent U shaped p contact layer is formed along three sides of the top surface of the underlying window layer. The p electrode is formed on the p contact layer centered on the closed end of the U shaped layer. An n contact layer is formed on an n cladding layer and centered in the open end of the U of the p contact layer. The n electrode is formed on the n contact layer. The n and p electrodes are electrically isolated from one another by either a trench or an insulator, situated between the electrodes.
    Type: Grant
    Filed: December 22, 2000
    Date of Patent: May 3, 2005
    Assignee: Dallan Luming Science & Technology Group Co., Ltd.
    Inventors: Heng Liu, Changhua Chen
  • Patent number: 6794731
    Abstract: A method for improving the operating stability of compound semiconductor minority carrier devices and the devices created using this method are described. The method describes intentional introduction of impurities into the layers adjacent to the active region, which impurities act as a barrier to the degradation process, particularly undesired defect formation and propagation. A preferred embodiment of the present invention uses O doping of III-V optoelectronic devices during an epitaxial growth process to improve the operating reliability of the devices.
    Type: Grant
    Filed: October 9, 1998
    Date of Patent: September 21, 2004
    Assignee: Lumileds Lighting U.S., LLC
    Inventors: Stephen A. Stockman, Daniel A. Steigerwald, Changhua Chen
  • Publication number: 20040075097
    Abstract: P-type layers of a GaN based light-emitting device are optimized for formation of Ohmic contact with metal. In a first embodiment, a p-type GaN transition layer with a resistivity greater than or equal to about 7 &OHgr;cm is formed between a p-type conductivity layer and a metal contact. In a second embodiment, the p-type transition layer is any III-V semiconductor. In a third embodiment, the p-type transition layer is a superlattice. In a fourth embodiment, a single p-type layer of varying composition and varying concentration of dopant is formed.
    Type: Application
    Filed: November 24, 2003
    Publication date: April 22, 2004
    Inventors: Werner K. Goetz, Michael D. Camras, Changhua Chen, Gina L. Christenson, R. Scott Kern, Chihping Kuo, Paul Scott Martin, Daniel A. Steigerwald
  • Patent number: 6657300
    Abstract: P-type layers of a GaN based light-emitting device are optimized for formation of Ohmic contact with metal. In a first embodiment, a p-type GaN transition layer with a resistivity greater than or equal to about 7 &OHgr;cm is formed between a p-type conductivity layer and a metal contact. In a second embodiment, the p-type transition layer is any III-V semiconductor. In a third embodiment, the p-type transition layer is a superlattice. In a fourth embodiment, a single p-type layer of varying composition and varying concentration of dopant is formed.
    Type: Grant
    Filed: January 5, 2001
    Date of Patent: December 2, 2003
    Assignee: Lumileds Lighting U.S., LLC
    Inventors: Werner K. Goetz, Michael D. Camras, Changhua Chen, Gina L. Christenson, R. Scott Kern, Chihping Kuo, Paul Scott Martin, Daniel A. Steigerwald
  • Patent number: 6630695
    Abstract: A GaN based three layer buffer structure disposed on a substrate, and having a GaN layer disposed on the three layer buffer structure, the GaN layer serving as a platform for growth of a light emitting structure thereon.
    Type: Grant
    Filed: July 8, 2002
    Date of Patent: October 7, 2003
    Inventors: Changhua Chen, James Dong, Heng Liu
  • Patent number: 6500257
    Abstract: An epitaxial material grown laterally in a trench allows for the fabrication of a trench-based semiconductor material that is substantially low in dislocation density. Initiating the growth from a sidewall of a trench minimizes the density of dislocations present in the lattice growth template, which minimizes the dislocation density in the regrown material. Also, by allowing the regrowth to fill and overflow the trench, the low dislocation density material can cover the entire surface of the substrate upon which the low dislocation density material is grown. Furthermore, with successive iterations of the trench growth procedure, higher quality material can be obtained. Devices that require a stable, high quality epitaxial material can then be fabricated from the low dislocation density material.
    Type: Grant
    Filed: April 17, 1998
    Date of Patent: December 31, 2002
    Assignee: Agilent Technologies, Inc.
    Inventors: Shih-Yuan Wang, Changhua Chen, Yong Chen, Scott W. Corzine, R. Scott Kern, Richard P. Schneider, Jr.
  • Patent number: 6495867
    Abstract: A GaN based three layer buffer on a sapphire substrate provides a template for growth of a high quality I GaN layer as a substitute substrate for growth of a Nitride based LED.
    Type: Grant
    Filed: July 26, 2000
    Date of Patent: December 17, 2002
    Assignee: AXT, Inc.
    Inventors: Changhua Chen, James Dong, Heng Liu
  • Publication number: 20020175337
    Abstract: A GaN based three layer buffer on a sapphire substrate provides a template for growth of a high quality I GaN layer as a substitute substrate for growth of a Nitride based LED.
    Type: Application
    Filed: July 8, 2002
    Publication date: November 28, 2002
    Applicant: AXT, Inc.
    Inventors: Changhua Chen, James Dong, Heng Liu
  • Publication number: 20020079500
    Abstract: A Semi-conductor light emitting diode comprises closely spaced n and p electrodes formed on the same side of a substrate to form an LED with a small foot-print. A semi transparent U shaped p contact layer is formed along three sides of the top surface of the underlying window layer. The p electrode is formed on the p contact layer centered on the closed end of the U. An n contact layer is formed on an n cladding layer and centered in the open end of the U of the p contact layer. The n electrode is formed on the n contact layer. The n and p electrodes are electrically isolated from one and the other by either a notch or an insulator, situated between the electrodes.
    Type: Application
    Filed: December 22, 2000
    Publication date: June 27, 2002
    Inventors: Heng Liu, Changhua Chen
  • Publication number: 20020008243
    Abstract: P-type layers of a GaN based light-emitting device are optimized for formation of Ohmic contact with metal. In a first embodiment, a p-type GaN transition layer with a resistivity greater than or equal to about 7 &OHgr;cm is formed between a p-type conductivity layer and a metal contact. In a second embodiment, the p-type transition layer is any III-V semiconductor. In a third embodiment, the p-type transition layer is a superlattice. In a fourth embodiment, a single p-type layer of varying composition and varying concentration of dopant is formed.
    Type: Application
    Filed: January 5, 2001
    Publication date: January 24, 2002
    Inventors: Werner K. Goetz, Michael D. Camras, Changhua Chen, Xiaoping Chen, Gina L. Christenson, R. Scott Kern, Chihping Kuo, Paul Scott Martin, Daniel A. Steigerwald
  • Publication number: 20020003237
    Abstract: A method for improving the operating stability of compound semiconductor minority carrier devices and the devices created using this method are described. The method describes intentional introduction of impurities into the layers adjacent to the active region, which impurities act as a barrier to the degradation process, particularly undesired defect formation and propagation. A preferred embodiment of the present invention uses O doping of III-V optoelectronic devices during an epitaxial growth process to improve the operating reliability of the devices.
    Type: Application
    Filed: October 9, 1998
    Publication date: January 10, 2002
    Inventors: STEPHEN A. STOCKMAN, DANIEL A. STEIGERWALD, CHANGHUA CHEN
  • Patent number: 6274399
    Abstract: In the present invention, an interfacial layer is added to a light-emitting diode or laser diode structure to perform the role of strain engineering and impurity gettering. A layer of GaN or AlxInyGa1−x−yN (0≦x≦1, 0≦y≦1) doped with Mg, Zn, Cd can be used for this layer. Alternatively, when using AlxInyGa1−x−yN (x>0), the layer may be undoped. The interfacial layer is deposited directly on top of the buffer layer prior to the growth of the n-type (GaN:Si) layer and the remainder of the device structure. The thickness of the interface layer varies from 0.01-10.0 &mgr;m.
    Type: Grant
    Filed: September 6, 2000
    Date of Patent: August 14, 2001
    Assignee: LumiLeds Lighting, U.S. LLC
    Inventors: R. Scott Kern, Changhua Chen, Werner Goetz, Chihping Kuo
  • Patent number: 6194742
    Abstract: In the present invention, an interfacial layer is added to a light-emitting diode or laser diode structure to perform the role of strain engineering and impurity gettering. A layer of GaN or AlxInyGal1-x-yN (0≦x≦1, 0≦y≦1) doped with Mg, Zn, Cd can be used for this layer. Alternatively, when using AlxInyGa1-x-yN (x>0), the layer may be undoped. The interfacial layer is deposited directly on top of the buffer layer prior to the growth of the n-type (GaN:Si) layer and the remainder of the device structure. The thickness of the interfacial layer varies from 0.01-10.0 &mgr;m.
    Type: Grant
    Filed: June 5, 1998
    Date of Patent: February 27, 2001
    Assignee: LumiLeds Lighting, U.S., LLC
    Inventors: R. Scott Kern, Changhua Chen, Werner Goetz, Chihping Kuo
  • Patent number: 5909051
    Abstract: A method for improving the operating stability of compound semiconductor minority carrier devices and the devices created using this method are described. The method describes intentional introduction of impurities into the layers adjacent to the active region, which impurities act as a barrier to the degradation process, particularly undesired defect formation and propagation. A preferred embodiment of the present invention uses O doping of III-V optoelectronic devices during an epitaxial growth process to improve the operating reliability of the devices.
    Type: Grant
    Filed: February 18, 1997
    Date of Patent: June 1, 1999
    Assignee: Hewlett-Packard Company
    Inventors: Stephen A. Stockman, Daniel A. Steigerwald, Changhua Chen