Patents Assigned to Alpha & Omega Semiconductor, Ltd.
  • Patent number: 7829989
    Abstract: An electronic package for containing at least a top packaging module vertically stacked on a bottom packaging module. Each of the packaging modules includes a semiconductor chip packaged and connected by via connectors and connectors disposed on a laminated board fabricated with a standard printed-circuit board process wherein the top and bottom packaging module further configured as a surface mountable modules for conveniently stacking and mounting to prearranged electrical contacts without using a leadframe. At least one of the top and bottom packaging modules is a multi-chip module (MCM) containing at least two semiconductor chips. At least one of the top and bottom packaging modules includes a ball grid array (BGA) for surface mounting onto the prearranged electrical contacts. At least one of the top and bottom packaging modules includes a plurality of solder bumps on one of the semiconductor chips for surface mounting onto the prearranged electrical contacts.
    Type: Grant
    Filed: December 22, 2005
    Date of Patent: November 9, 2010
    Assignee: Alpha & Omega Semiconductor, Ltd.
    Inventors: Ming Sun, Yueh Se Ho
  • Patent number: 7824977
    Abstract: A semiconductor wafer includes at least a partially manufactured high voltage transistor covered by a high-voltage low voltage decoupling layer and at least a partially manufactured low voltage transistor with the high-voltage low-voltage decoupling layer etched off for further performance of a low-voltage manufacturing process thereon. The high-voltage low-voltage decoupling layer comprising a high temperature oxide (HTO) oxide layer of about 30-150 Angstroms and a low-pressure chemical vapor deposition (LPCVD) nitride layer.
    Type: Grant
    Filed: March 27, 2007
    Date of Patent: November 2, 2010
    Assignee: Alpha & Omega Semiconductor, Ltd.
    Inventors: YongZhong Hu, Sung-Shan Tai
  • Patent number: 7808102
    Abstract: A DC-DC boost converter in multi-die package is proposed having an output Schottky diode and a low-side vertical MOSFET controlled by a power regulating controller (PRC). The multi-die package includes a single die pad with the Schottky diode placed there on side by side with the vertical MOSFET. The PRC die is attached atop the single die pad via an insulating die bond. Alternatively, the single die pad is grounded. The vertical MOSFET is a top drain vertical N-channel FET, the substrate of Schottky diode die is its anode. The Schottky diode and the vertical MOSFET are stacked atop the single die pad. The PRC is attached atop the single die pad via a standard conductive die bond. The Schottky diode die can be supplied in a flip-chip configuration with cathode being its substrate. Alternatively, the Schottky diode is supplied with anode being its substrate without the flip-chip configuration.
    Type: Grant
    Filed: July 31, 2007
    Date of Patent: October 5, 2010
    Assignee: Alpha & Omega Semiconductor, Ltd.
    Inventors: François Hébert, Ming Sun
  • Patent number: 7805687
    Abstract: A method of performing a programming, testing and trimming operation is disclosed in this invention. The method includes a step of applying a programming circuit for programming an OTP memory for probing and sensing one of three different states of the OTP memory for carrying out a trimming operation using one of the three states of the OTP memory whereby a higher utilization of OTP memory cells is achieved. Selecting and programming two conductive circuits of the OTP into two different operational characteristics thus enables the storing and sensing one of the three different states of the OTP memory. These two conductive circuits may include two different transistors for programming into a linear resistor and a nonlinear resistor with different current conducting characteristics. The programming processes include application of a high voltage and different programming currents thus generating different operational characteristics of these two transistors.
    Type: Grant
    Filed: September 30, 2006
    Date of Patent: September 28, 2010
    Assignee: Alpha & Omega Semiconductor, Ltd.
    Inventors: YongZhong Hu, Yu Cheng Chang, Sung-Shan Tai
  • Patent number: 7799646
    Abstract: A semiconductor device includes a main field effect transistor (FET) and one or more sense FETs, and a common gate pad. The main FET and the one or more sense FETs are formed in a common substrate. The main FET and each of the sense FETs include a source terminal, a gate terminal and a drain terminal. The common gate pad connects the gate terminals of the main FET and the one or more sense FETs. An electrical isolation is disposed between the gate terminals of the main FET and the one or more sense FETs. Embodiments of this invention may be applied to both N-channel and P-channel MOSFET devices.
    Type: Grant
    Filed: April 7, 2008
    Date of Patent: September 21, 2010
    Assignee: Alpha & Omega Semiconductor, Ltd
    Inventors: Yi Su, Anup Bhalla, Daniel Ng
  • Patent number: 7795108
    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 material layer thereby defining a test structure that lies underneath the resist mask. The resist mask does not cover the trench. The material is isotropically etched and a signal related to a resistance change of the test structure is measured. A lateral undercut DL of the test structure is determined from the signal and an etch depth DT is determined from DL. The wafer may comprise one or more test structures forming a bridge circuit; one or more metal contacts that electrically connect the test structures through contact holes: and resist layer including over the test structures.
    Type: Grant
    Filed: March 6, 2009
    Date of Patent: September 14, 2010
    Assignee: Alpha & Omega Semiconductor, Ltd
    Inventors: Tiesheng Li, Yu Wang, Yingying Lou, Anup Bhalla
  • Patent number: 7795987
    Abstract: A transient voltage suppressing (TVS) circuit with uni-directional blocking and symmetric bi-directional blocking capabilities integrated with an electromagnetic interference (EMI) filter supported on a semiconductor substrate of a first conductivity type. The TVS circuit integrated with the EMI filter further includes a ground terminal disposed on the surface for the symmetric bi-directional blocking structure and at the bottom of the semiconductor substrate for the uni-directional blocking structure and an input and an output terminal disposed on a top surface with at least a Zener diode and a plurality of capacitors disposed in the semiconductor substrate to couple the ground terminal to the input and output terminals with a direct capacitive coupling without an intermediate floating body region.
    Type: Grant
    Filed: June 16, 2007
    Date of Patent: September 14, 2010
    Assignee: Alpha & Omega Semiconductor, Ltd.
    Inventor: Madhur Bobde
  • Patent number: 7790549
    Abstract: This invention discloses a semiconductor power device disposed in a semiconductor substrate and the semiconductor substrate has a plurality of deep trenches. The deep trenches are filled with an epitaxial layer thus forming a top epitaxial layer covering areas above a top surface of the deep trenches covering over the semiconductor substrate. The semiconductor power device further includes a plurality of transistor cells disposed in the top epitaxial layer whereby a device performance of the semiconductor power device is dependent on a depth of the deep trenches and not dependent on a thickness of the top epitaxial layer. Each of the plurality of transistor cells includes a trench DMOS transistor cell having a trench gate opened through the top epitaxial layer and filled with a gate dielectric material.
    Type: Grant
    Filed: August 20, 2008
    Date of Patent: September 7, 2010
    Assignee: Alpha & Omega Semiconductor, Ltd
    Inventor: François Hébert
  • Patent number: 7786531
    Abstract: This invention discloses a new trenched vertical semiconductor power device that includes a capacitor formed between a conductive layer covering over an inter-dielectric layer disposed on top of a trenched gate. In a specific embodiment, the trenched vertical semiconductor power device may be a trenched metal oxide semiconductor field effect transistor (MOSFET) power device. The trenched gate is a trenched polysilicon gate and the conductive layer is a second polysilicon layer covering an inter-poly dielectric layer disposed on top of the trenched polysilicon gate. The conductive layer is further connected to a source of the vertical power device.
    Type: Grant
    Filed: July 14, 2005
    Date of Patent: August 31, 2010
    Assignee: Alpha & Omega semiconductor Ltd.
    Inventors: Sik K. Lui, Anup Bhalla
  • Patent number: 7781826
    Abstract: A vertical TVS (VTVS) circuit includes a semiconductor substrate for supporting the VTVS device thereon having a heavily doped layer extending to the bottom of substrate. Deep trenches are provided for isolation between multi-channel VTVS. Trench gates are also provided for increasing the capacitance of VTVS with integrated EMI filter.
    Type: Grant
    Filed: November 16, 2006
    Date of Patent: August 24, 2010
    Assignee: Alpha & Omega Semiconductor, Ltd.
    Inventors: Shekar Mallikararjunaswamy, Madhur Bobde
  • Patent number: 7764105
    Abstract: This invention discloses a new MOSFET device. The MOSFET device has an improved operation characteristic achieved by connecting a shunt FET of low impedance to the MOSFET device. The shunt FET is to shunt a transient current therethrough. The shunt FET is employed for preventing an inadvertent turning on of the MOSFET device. The inadvertent turning on of the MOSFET may occur when a large voltage transient occurs at the drain of the MOSFET device. By connecting the gate of the shunt FET to the drain of the MOSFET device, a low impedance path is provided at the right point of time during the circuit operation to shunt the current without requiring any external circuitry.
    Type: Grant
    Filed: May 27, 2008
    Date of Patent: July 27, 2010
    Assignee: Alpha & Omega Semiconductor, Ltd
    Inventors: Anup Bhalla, Sik K. Lui
  • Patent number: 7755379
    Abstract: This invention discloses a circuit for performing an unclamped inductive test on a metal oxide semiconductor field effect transistor (MOSFET) device driven by a gate driver. The circuit includes a current sense circuit for measuring an unclamped inductive testing (UIS) current that increases with an increase of a pulse width inputted from the gate driver to the MOSFET device wherein the current sensing circuit is provided to turn off the gate driver when a predefined UIS current is reached. The test circuit further includes a MOSFET failure detection circuit connected to a drain terminal of the MOSFET device for measuring a drain voltage change for detecting the MOSFET failure during the UIS test. The test circuit further includes a first switch for switching ON/OFF a power supply to the MOSFET device to and a second switch connected between a drain and source terminal of the MOSFET.
    Type: Grant
    Filed: April 8, 2008
    Date of Patent: July 13, 2010
    Assignee: Alpha & Omega Semiconductor, Ltd
    Inventors: Sik K Lui, Anup Bhalla
  • Patent number: 7750447
    Abstract: A high voltage and high power boost converter is disclosed. The boost converter includes a boost converter IC and a discrete Schottky diode, both of which are co-packaged on a standard single common die pad.
    Type: Grant
    Filed: June 11, 2007
    Date of Patent: July 6, 2010
    Assignee: Alpha & Omega Semiconductor, Ltd
    Inventors: Allen Chang, Wai-Keung Peter Cheng
  • Publication number: 20100163979
    Abstract: A semiconductor package may comprise a semiconductor substrate, a MOSFET device having a plurality cells formed on the substrate, and a source region common to all cells disposed on a bottom of the substrate. Each cell comprises a drain region on a top of the semiconductor device, a gate to control a flow of electrical current between the source and drain regions, a source contact proximate the gate; and an electrical connection between the source contact and source region. At least one drain connection is electrically coupled to the drain region. Source, drain and gate pads are electrically connected to the source region, drain region and gates of the devices. The drain, source and gate pads are formed on one surface of the semiconductor package. The cells are distributed across the substrate, whereby the electrical connections between the source contact of each device and the source region are distributed across the substrate.
    Type: Application
    Filed: December 29, 2008
    Publication date: July 1, 2010
    Applicant: ALPHA & OMEGA SEMICONDUCTOR, LTD
    Inventor: Francois Hebert
  • Patent number: 7745878
    Abstract: This invention discloses a semiconductor power device that includes a plurality of power transistor cells surrounded by a trench opened in a semiconductor substrate. At least one active cell further includes a trenched source contact opened between the trenches wherein the trenched source contact opened through a source region into a body region for electrically connecting the source region to a source metal disposed on top of an insulation layer wherein a trench bottom surface of the trenched source contact further covered with a conductive material to function as an integrated Schottky barrier diode in said active cell. A shielding structure is disposed at the bottom and insulated from the trenched gate to provide shielding effect for both the trenched gate and the Schottky diode.
    Type: Grant
    Filed: November 18, 2008
    Date of Patent: June 29, 2010
    Assignee: Alpha & Omega Semiconductor, Ltd
    Inventors: Anup Bhalla, Sik K Lui
  • Patent number: 7737522
    Abstract: A Schottky diode includes at least a trenched opened in a semiconductor substrate doped with a dopant of a first conductivity type wherein the trench is filled with a Schottky junction barrier metal. The Schottky diode further includes one or more dopant region of a second conductivity type surrounding sidewalls of the trench distributed along the depth of the trench for shielding a reverse leakage current through the sidewalls of the trench. The Schottky diode further includes a bottom-doped region of the second conductivity type surrounding a bottom surface of the trench and a top-doped region of the second conductivity type surrounding a top portion of the sidewalls of the trench. In a preferred embodiment, the first conductivity type is a N-type conductivity type and the middle-depth dopant region comprising a P-dopant region.
    Type: Grant
    Filed: September 30, 2006
    Date of Patent: June 15, 2010
    Assignee: Alpha & Omega Semiconductor, Ltd.
    Inventors: Sik K Lui, Anup Bhalla
  • Patent number: 7728385
    Abstract: A device structure is disclosed for preventing gate oxide damage of a trench MOSFET during wafer processing while adding an ESD protection module atop the trench MOSFET. The ESD protection module has a low temperature oxide (LTO) bottom layer whose patterning process was found to cause the gate oxide damage before. The present invention structure includes a semiconductor substrate having an active area and a termination area; numerous trench MOSFET cells disposed in the active area; numerous electrostatic discharge (ESD) diodes disposed above the semiconductor substrate in the termination area; and an insulation layer comprising Oxide/Nitride/Oxide (ONO) sandwiched between the ESD diodes and the semiconductor substrate. In one embodiment, the active area does not contain the ONO insulation layer.
    Type: Grant
    Filed: July 22, 2009
    Date of Patent: June 1, 2010
    Assignee: Alpha & Omega Semiconductor, Ltd.
    Inventors: Mengyu Pan, Zengyi He, Kaiyu Chen
  • Patent number: 7670908
    Abstract: This invention discloses semiconductor device that includes a top region and a bottom region with an intermediate region disposed between said top region and said bottom region with a controllable current path traversing through the intermediate region. The semiconductor device further includes a trench with padded with insulation layer on sidewalls extended from the top region through the intermediate region toward the bottom region wherein the trench includes randomly and substantially uniformly distributed nano-nodules as charge-islands in contact with a drain region below the trench for electrically coupling with the intermediate region for continuously and uniformly distributing a voltage drop through the current path.
    Type: Grant
    Filed: January 22, 2007
    Date of Patent: March 2, 2010
    Assignee: Alpha & Omega Semiconductor, Ltd.
    Inventors: François Hébert, Tao Feng
  • Patent number: 7671439
    Abstract: A Schottky diode includes a Schottky barrier and a plurality of dopant regions disposed near the Schottky barrier as floating islands to function as PN junctions for preventing a leakage current generated from a reverse voltage. At least a trench opened in a semiconductor substrate with a Schottky barrier material disposed therein constitutes the Schottky barrier. The Schottky barrier material may also be disposed on sidewalls of the trench for constituting the Schottky barrier. The trench may be filled with the Schottky barrier material composed of Ti/TiN or a tungsten metal disposed therein for constituting the Schottky barrier. The trench is opened in a N-type semiconductor substrate and the dopant regions includes P-doped regions disposed under the trench constitute the floating islands. The P-doped floating islands may be formed as vertical arrays under the bottom of the trench.
    Type: Grant
    Filed: December 1, 2006
    Date of Patent: March 2, 2010
    Assignee: Alpha & Omega Semiconductor, Ltd.
    Inventors: Ji Pan, Anup Bhalla
  • Patent number: 7659570
    Abstract: This invention discloses a new switching device supported on a semiconductor that includes a drain disposed on a first surface and a source region disposed near a second surface of said semiconductor opposite the first surface. The switching device further includes an insulated gate electrode disposed on top of the second surface for controlling a source to drain current. The switching device further includes a source electrode interposed into the insulated gate electrode for substantially preventing a coupling of an electrical field between the gate electrode and an epitaxial region underneath the insulated gate electrode. The source electrode further covers and extends over the insulated gate for covering an area on the second surface of the semiconductor to contact the source region. The semiconductor substrate further includes an epitaxial layer disposed above and having a different dopant concentration than the drain region.
    Type: Grant
    Filed: May 9, 2005
    Date of Patent: February 9, 2010
    Assignee: Alpha & Omega Semiconductor Ltd.
    Inventors: Anup Bhalla, Daniel Ng, Tiesheng Li, Sik K. Lui