Patents Assigned to Alpha & Omega Semiconductor, Ltd.
  • Patent number: 8105905
    Abstract: A novel integration scheme for forming power MOSFET, particularly forming salicides for both gate and mesa contact regions, as well as using multiple energy contact implants through the salicided layer to form conductive body contacts which short to the source region by the salicides.
    Type: Grant
    Filed: November 8, 2010
    Date of Patent: January 31, 2012
    Assignee: Alpha & Omega Semiconductor, Ltd.
    Inventors: Yongzhong Hu, Sung-Shan Tai
  • Publication number: 20120001176
    Abstract: A semiconductor device wafer includes a test structure. The test structure includes a layer of material having an angle-shaped test portion disposed on at least a portion of a surface of the semiconductor wafer. A ruler marking on the surface of the semiconductor wafer proximate the test portion is adapted to facilitate measurement of a change in length of the test portion.
    Type: Application
    Filed: September 13, 2011
    Publication date: January 5, 2012
    Applicant: ALPHA & OMEGA SEMICONDUCTOR, LTD.
    Inventors: Yingying Lou, Tiesheng Li, Yu Wang, Anup Bhalla
  • Patent number: 8089139
    Abstract: A TSOP (Thin Small Outline Package) contains a MOSFET and a Schottky diode. The MOSFET has a source terminal a gate terminal and a drain terminal. The Schottky diode has a cathode terminal, a anode terminal. The TSOP contains the MOSFET and the Schottky diode with a special configuration by placing the drain terminal of the MOSFET and the anode terminal of the Schottky diode on a same side. Specifically, the TSOP implements a leadframe that comprises a plurality of leads. The drain terminal of the MOSFET and the anode terminal extends outside of the TSOP separate on the same side of the package.
    Type: Grant
    Filed: October 9, 2005
    Date of Patent: January 3, 2012
    Assignee: Alpha & Omega Semiconductor, Ltd.
    Inventors: Zhengyu Shi, Limin Wang, Lei Shi
  • Publication number: 20110316090
    Abstract: A boost converter for high power and high output voltage applications includes a low voltage controller integrated circuit and a high voltage, vertical, discrete field effect transistor, both of which are packed in a single package on separate electrically isolated die pads.
    Type: Application
    Filed: September 1, 2011
    Publication date: December 29, 2011
    Applicant: ALPHA & OMEGA SEMICONDUCTOR, LTD.
    Inventors: ALLEN CHANG, Wai-Keung Peter Cheng
  • Patent number: 8067288
    Abstract: This invention discloses a method for manufacturing a one-time programmable (OTP) memory includes a first and second MOS transistors connected in parallel and controlled by a common gate formed with a single polysilicon stripe. The method further comprises a step of implanting a drift region in a substrate region below a drain and source of the first and second MOS transistors counter doping a lightly dope drain (LDD) encompassing and surrounding a drain and a source of the first MOS transistor having a different threshold voltage than the second MOS transistor not reached by the drift region.
    Type: Grant
    Filed: October 9, 2009
    Date of Patent: November 29, 2011
    Assignee: Alpha & Omega Semiconductor, Ltd
    Inventor: Shekar Mallikararjunaswamy
  • Publication number: 20110278665
    Abstract: High-mobility vertical trench DMOSFETs and methods for manufacturing are disclosed. A source region, a drain region or a channel region of a high-mobility vertical trench DMOSFET may comprise silicon germanium (SiGe) that increases the mobility of the charge carriers in the channel region. In some embodiments the channel region may be strained to increase channel charge carriers mobility.
    Type: Application
    Filed: July 22, 2011
    Publication date: November 17, 2011
    Applicant: ALPHA & OMEGA SEMICONDUCTOR, LTD
    Inventor: FRANÇOIS HÉBERT
  • Patent number: 8058687
    Abstract: This invention discloses a trenched metal oxide semiconductor field effect transistor (MOSFET) cell. The trenched MOSFET cell includes a trenched gate opened from a top surface of the semiconductor substrate surrounded by a source region encompassed in a body region above a drain region disposed on a bottom surface of a substrate. The trenched gate further includes at least two mutually insulated trench-filling segments each filled with materials of different work functions. In an exemplary embodiment, the trenched gate includes a polysilicon segment at a bottom portion of the trenched gate and a metal segment at a top portion of the trenched gate.
    Type: Grant
    Filed: January 30, 2007
    Date of Patent: November 15, 2011
    Assignee: Alpha & Omega Semiconductor, Ltd.
    Inventors: Sung-Shan Tai, YongZhong Hu
  • Patent number: 8053298
    Abstract: This invention discloses an improved semiconductor power device includes a plurality of power transistor cells wherein each cell further includes a planar gate padded by a gate oxide layer disposed on top of a drift layer constituting an upper layer of a semiconductor substrate wherein the planar gate further constituting a split gate including a gap opened in a gate layer whereby the a total surface area of the gate is reduced. The transistor cell further includes a JFET (junction field effect transistor) diffusion region disposed in the drift layer below the gap of the gate layer wherein the JFET diffusion region having a higher dopant concentration than the drift region for reducing a channel resistance of the semiconductor power device.
    Type: Grant
    Filed: March 16, 2009
    Date of Patent: November 8, 2011
    Assignee: Alpha & Omega Semiconductor Ltd.
    Inventors: Anup Bhalla, Francois Hebert, Daniel S. Ng
  • Patent number: 8053808
    Abstract: A semiconductor power device supported on a semiconductor substrate includes a plurality of transistor cells each having a source and a drain with a gate to control an electric current transmitted between the source and the drain. The semiconductor further includes a source metal connected to the source region, and a gate metal configured as a metal stripe surrounding a peripheral region of the substrate connected to a gate pad wherein the gate metal and the gate pad are separated from the source metal by a metal gap. The semiconductor power device further includes an ESD protection circuit includes a plurality of doped polysilicon regions of opposite conductivity types constituting ESD diodes extending across the metal gap and connected between the gate metal and the source metal on the peripheral region of the substrate.
    Type: Grant
    Filed: May 21, 2007
    Date of Patent: November 8, 2011
    Assignee: Alpha & Omega Semiconductor, Ltd.
    Inventors: Yi Su, Anup Bhalla, Daniel Ng, Wei Wang, Ji Pan
  • Patent number: 8053315
    Abstract: This invention discloses a method of manufacturing a trenched semiconductor power device with split gate filling a trench opened in a semiconductor substrate wherein the split gate is separated by an inter-poly insulation layer disposed between a top and a bottom gate segments. The method further includes a step of forming the inter-poly layer by applying a RTP process after a HDP oxide deposition process to bring an etch rate of the HDP oxide layer close to an etch rate of a thermal oxide.
    Type: Grant
    Filed: October 16, 2009
    Date of Patent: November 8, 2011
    Assignee: Alpha & Omega Semiconductor, LTD
    Inventors: Sung-Shan Tai, Yong-Zhong Hu, François Hébert, Hong Chang, Mengyu Pan, Yingying Lou, Yu Wang
  • Patent number: 8049315
    Abstract: A semiconductor package assembly may include a lead frame having a die bonding pad and plurality of leads coupled to the first die bonding pad. A vertical semiconductor device may be bonded to the die bonding pad. The device may have a conductive pad electrically connected to one lead through a first bond wire. An electrically isolated conductive trace may be formed from a layer of conductive material of the first semiconductor device. The conductive trace provides an electrically conductive path between the first bond wire and a second bond wire. The conductive path may either pass underneath a third bond wire thereby avoiding the third bond wire crossing another bond wire, or the conductive path may result in a reduced length for the first and second bond wires that is less than a predetermined maximum length.
    Type: Grant
    Filed: January 14, 2011
    Date of Patent: November 1, 2011
    Assignee: Alpha & Omega Semiconductors, Ltd.
    Inventors: Jun Lu, Anup Bhalla, Xiaobin Wang, Allen Chang, Kenny Man Sheng Hu, Xiaotian Zhang
  • Patent number: 8035159
    Abstract: This invention discloses a semiconductor power device. The trenched semiconductor power device includes a trenched gate, opened from a top surface of a semiconductor substrate, surrounded by a source region encompassed in a body region near the top surface above a drain region disposed on a bottom surface of a substrate. The semiconductor power device further includes an implanting-ion block disposed above the top surface on a mesa area next to the body region having a thickness substantially larger than 0.3 micron for blocking body implanting ions and source ions from entering into the substrate under the mesa area whereby masks for manufacturing the semiconductor power device can be reduced.
    Type: Grant
    Filed: April 30, 2007
    Date of Patent: October 11, 2011
    Assignee: Alpha & Omega Semiconductor, Ltd.
    Inventors: Anup Bhalla, François Hébert, Sung-Shan Tai, Sik K Lui
  • Publication number: 20110227155
    Abstract: A main FET and one or more sense FETs are formed in a common substrate. The main FET and sense FET(s) include a source terminal, a gate terminal and a drain terminal. The common gate pad connects the gate terminals of the main FET and sense FET(s). An electrical isolation may be between the gate terminals of the main FET and the sense FET(s). A sense pad in electrical contact with the source of the one or more sense FETs does not overlap an area of the device containing the sense FET(s). It is emphasized that this abstract is provided to comply with the 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: May 31, 2011
    Publication date: September 22, 2011
    Applicant: ALPHA & OMEGA SEMICONDUCTOR, LTD.
    Inventors: Yi Su, Anup Bhalla, Daniel Ng
  • Patent number: 8021563
    Abstract: A method for determining the depth etch, a method of forming a shielded gate trench (SGT) structure and a semiconductor device wafer are disclosed. A material layer is formed over part of a substrate having a trench. The material fills the trench. A resist mask is placed over a test portion of the layer of material. The resist mask does not cover the trench. The layer of material is isotropically etched. An etch depth may be determined from a characteristic of etching of the material underneath the mask. Such a method may be used for forming SGT structures. The wafer may comprise a layer of material disposed on at least a portion of a surface of semiconductor wafer; a resist mask comprising an angle-shaped test portion disposed over a portion of the layer of material; and a ruler marking on the surface of the substrate proximate the test portion.
    Type: Grant
    Filed: March 23, 2007
    Date of Patent: September 20, 2011
    Assignee: Alpha & Omega Semiconductor, Ltd
    Inventors: Yingying Lou, Tiesheng Li, Yu Wang, Anup Bhalla
  • Patent number: 8022482
    Abstract: A trenched semiconductor power device includes a trenched gate insulated by a gate insulation layer and surrounded by a source region encompassed in a body region above a drain region disposed on a bottom surface of a semiconductor substrate. The source region surrounding the trenched gate includes a metal of low barrier height to function as a Schottky source. The metal of low barrier height further may include a PtSi or ErSi layer. In a preferred embodiment, the metal of low barrier height further includes an ErSi layer. The metal of low barrier height further may be a metal silicide layer having the low barrier height. A top oxide layer is disposed under a silicon nitride spacer on top of the trenched gate for insulating the trenched gate from the source region. A source contact disposed in a trench opened into the body region for contacting a body-contact dopant region and covering with a conductive metal layer such as a Ti/TiN layer.
    Type: Grant
    Filed: February 14, 2006
    Date of Patent: September 20, 2011
    Assignee: Alpha & Omega Semiconductor, Ltd
    Inventors: Yongzhong Hu, Sung-Shan Tai
  • Patent number: 8008897
    Abstract: A boost converter for high power and high output voltage applications includes a low voltage controller integrated circuit and a high voltage, vertical, discrete field effect transistor, both of which are packed in a single package.
    Type: Grant
    Filed: June 11, 2007
    Date of Patent: August 30, 2011
    Assignee: Alpha & Omega Semiconductor, Ltd
    Inventors: Allen Chang, Wai-Keung Peter Cheng
  • Patent number: 8008716
    Abstract: This invention discloses bottom-source lateral diffusion MOS (BS-LDMOS) device. The device has a source region disposed laterally opposite a drain region near a top surface of a semiconductor substrate supporting a gate thereon between the source region and a drain region. The BS-LDMOS device further has a combined sinker-channel region disposed at a depth in the semiconductor substrate entirely below a body region disposed adjacent to the source region near the top surface wherein the combined sinker-channel region functioning as a buried source-body contact for electrically connecting the body region and the source region to a bottom of the substrate functioning as a source electrode. A drift region is disposed near the top surface under the gate and at a distance away from the source region and extending to and encompassing the drain region.
    Type: Grant
    Filed: September 17, 2006
    Date of Patent: August 30, 2011
    Assignee: Alpha & Omega Semiconductor, Ltd
    Inventors: Sik K Lui, François Hébert, Anup Bhalla
  • Patent number: 8008747
    Abstract: This invention discloses a semiconductor power device disposed on a semiconductor substrate supporting an epitaxial layer as a drift region composed of an epitaxial layer. The semiconductor power device further includes a super-junction structure includes a plurality of doped sidewall columns disposed in a multiple of epitaxial layers. The epitaxial layer have a plurality of trenches opened and filled with the multiple epitaxial layer therein with the doped columns disposed along sidewalls of the trenches disposed in the multiple of epitaxial layers.
    Type: Grant
    Filed: February 28, 2008
    Date of Patent: August 30, 2011
    Assignee: Alpha & Omega Semiconductor, Ltd.
    Inventors: François Hébert, Anup Bhalla
  • Patent number: 8000124
    Abstract: A symmetrical blocking transient voltage suppressing (TVS) circuit for suppressing a transient voltage includes an NPN transistor having a base electrically connected to a common source of two transistors whereby the base is tied to a terminal of a low potential in either a positive or a negative voltage transient. The two transistors are two substantially identical transistors for carrying out a substantially symmetrical bi-directional clamping a transient voltage. These two transistors further include a first and second MOSFET transistors having an electrically interconnected source. The first MOSFET transistor further includes a drain connected to a high potential terminal and a gate connected to the terminal of a low potential and the second MOSFET transistor further includes a drain connected to the terminal of a low potential terminal and a gate connected to the high potential terminal.
    Type: Grant
    Filed: June 25, 2009
    Date of Patent: August 16, 2011
    Assignee: Alpha & Omega Semiconductor, Ltd
    Inventor: Madhur Bobde
  • Patent number: 7999363
    Abstract: A resetable over-current self-protecting semiconductor power device comprises a vertical power semiconductor chip and an over-current protection layer composed of current limiting material such as a PTC material. The over-current protection layer may be sandwiched between the vertical power semiconductor chip and a conductive plate, which could be a leadframe, a metal plate, a PCB plate or a PCB that the device is mounted on.
    Type: Grant
    Filed: January 25, 2007
    Date of Patent: August 16, 2011
    Assignee: Alpha & Omega Semiconductor, Ltd
    Inventors: François Hébert, Ming Sun