Patents Assigned to Alpha & Omega Semiconductor, Ltd.
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Patent number: 7994005Abstract: 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: GrantFiled: November 1, 2007Date of Patent: August 9, 2011Assignee: Alpha & Omega Semiconductor, LtdInventor: François Hébert
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Patent number: 7977930Abstract: A voltage/current control apparatus and method are disclosed. The apparatus includes a low-side field effect transistor (FET) having a source, a gate and a drain, a high-side field effect transistor (FET) having a source, a gate and a drain, a gate driver integrated circuit (IC), a sample and hold circuit, and a comparator configured to produce a trigger signal at the output when a sum of the first and second input signals is equal to a sum of the third and fourth input signals, wherein the trigger signal is configured to trigger a beginning of a new cycle by turning the gate of the high-side FET “on” and the gate of the low-side FET “off”.Type: GrantFiled: May 19, 2009Date of Patent: July 12, 2011Assignee: Alpha & Omega Semiconductor, LtdInventor: Yu Cheng Chang
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Patent number: 7971340Abstract: An inductor may include a planar ferrite core. A first group of one or more grooves is formed in a first side of the ferrite core. A second group of two or more grooves is formed in a second side of the ferrite core. The grooves in the first and second groups are oriented such that each groove in the first group overlaps with two corresponding grooves in the second group. A first plurality of vias communicates through the ferrite core between the first and second sides of the ferrite core. Each via is located where a groove in the first group overlaps with a groove in the second group. A conductive material is disposed in the first and second groups of grooves and in the vias to form an inductor coil.Type: GrantFiled: January 14, 2011Date of Patent: July 5, 2011Assignee: Alpha & Omega Semiconductor, LtdInventors: François Hébert, Tao Feng, Jun Lu
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Patent number: 7955893Abstract: Power wafer level chip scale package (CSP) and process of manufacture are enclosed. The power wafer level chip scale package includes all source, gate and drain electrodes located on one side of the device, which is convenient for mounting to a printed circuit board (PCB) with solder paste.Type: GrantFiled: January 31, 2008Date of Patent: June 7, 2011Assignee: Alpha & Omega Semiconductor, LtdInventors: Tao Feng, François Hébert, Ming Sun, Yueh-Se Ho
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Patent number: 7956384Abstract: A semiconductor power device supported on a semiconductor substrate that includes a plurality of transistor cells, each cell has a source and a drain region disposed on opposite sides of a gate region in the semiconductor substrate. A gate electrode is formed as an electrode layer on top of the gate region for controlling an electric current transmitted between the source and the drain regions. The gate electrode layer disposed on top of the semiconductor substrate is patterned into a wave-like shaped stripes for substantially increasing an electric current conduction area between the source and drain regions across the gate.Type: GrantFiled: June 23, 2006Date of Patent: June 7, 2011Assignee: Alpha & Omega Semiconductor Ltd.Inventor: Shekar Mallikararjunaswamy
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Patent number: 7952144Abstract: 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: GrantFiled: August 20, 2010Date of Patent: May 31, 2011Assignee: Alpha & Omega Semiconductor, LtdInventors: Yi Su, Anup Bhalla, Daniel Ng
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Patent number: 7952139Abstract: This invention discloses a semiconductor power device that includes an active cell area having a plurality of power transistor cells. Each of said power transistor cells has a planar Schottky diode that includes a Schottky junction barrier metal covering areas above gaps between separated body regions between two adjacent power transistor cells. The separated body regions further provide a function of adjusting a leakage current of said Schottky diode in each of said power transistor cells. Each of the planar Schottky diodes further includes a Shannon implant region disposed in a gap between the separated body regions of two adjacent power transistor cells for further adjusting a leakage current of said Schottky diode. Each of the power transistor cells further includes heavy body doped regions in the separated body regions next to source regions surrounding said Schottky diode forming a junction barrier Schottky (JBS) pocket region.Type: GrantFiled: June 30, 2008Date of Patent: May 31, 2011Assignee: Alpha & Omega Semiconductor Ltd.Inventors: Anup Bhalla, Xiaobin Wang, Moses Ho
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Patent number: 7948346Abstract: An inductor may include a planar ferrite core. A first group of one or more grooves is formed in a first side of the ferrite core. A second group of two or more grooves is formed in a second side of the ferrite core. The grooves in the first and second groups are oriented such that each groove in the first group overlaps with two corresponding grooves in the second group. A first plurality of vias communicates through the ferrite core between the first and second sides of the ferrite core. Each via is located where a groove in the first group overlaps with a groove in the second group. A conductive material is disposed in the first and second groups of grooves and in the vias to form an inductor coil.Type: GrantFiled: June 30, 2008Date of Patent: May 24, 2011Assignee: Alpha & Omega Semiconductor, LtdInventors: Francois Hébert, Tao Feng, Jun Lu
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Patent number: 7933102Abstract: This invention discloses an electronic device formed as an integrated circuit (IC) wherein the electronic device further includes a transient voltage suppressing (TVS) circuit. The TVS circuit includes a triggering Zener diode connected between an emitter and a collector of a bipolar-junction transistor (BJT) wherein the Zener diode having a reverse breakdown voltage BV less than or equal to a BVceo of the BJT where BVceo stands for a collector to emitter breakdown voltage with base left open. The TVS circuit further includes a rectifier connected in parallel to the BJT for triggering a rectified current through the rectifier for further limiting an increase of a reverse blocking voltage.Type: GrantFiled: May 15, 2009Date of Patent: April 26, 2011Assignee: Alpha & Omega Semiconductor, Ltd.Inventor: Shekar Mallikararjunaswamy
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Patent number: 7932148Abstract: This invention discloses an improved trenched metal oxide semiconductor field effect transistor (MOSFET) device that includes a trenched gate surrounded by a source region encompassed in a body region above a drain region disposed on a bottom surface of a substrate. The MOSFET cell further includes a shielded gate trench (SGT) structure below and insulated from the trenched gate. The SGT structure is formed substantially as a round hole having a lateral expansion extended beyond the trench gate and covered by a dielectric liner layer filled with a trenched gate material. The round hole is formed by an isotropic etch at the bottom of the trenched gate and is insulated from the trenched gate by an oxide insulation layer. The round hole has a lateral expansion beyond the trench walls and the lateral expansion serves as a vertical alignment landmark for controlling the depth of the trenched gate.Type: GrantFiled: February 9, 2009Date of Patent: April 26, 2011Assignee: Alpha & Omega Semiconductor, LtdInventors: Hong Chang, Sung-Shan Tai, Tiesheng Li, Yu Wang
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Patent number: 7919817Abstract: An electrostatic discharge (ESD) protection circuit includes a triggering diode that includes a junction between a P-grade (PG) region and an N-well. The PG region has a dopant profile equivalent to a P-drain dopant profile of a PMOS transistor having a breakdown voltage represented by V whereby the triggering diode for conducting a current when a voltage greater than the breakdown voltage V is applied. In an exemplary embodiment, the dopant profile of the PG region includes two dopant implant profiles that include a shallow implant profile with a higher dopant concentration and a deep implant profile with a lower dopant concentration.Type: GrantFiled: May 16, 2008Date of Patent: April 5, 2011Assignee: Alpha & Omega Semiconductor Ltd.Inventor: Shekar Mallikarjunaswamy
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Patent number: 7884454Abstract: 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: GrantFiled: September 11, 2008Date of Patent: February 8, 2011Assignee: Alpha & Omega Semiconductor, LtdInventors: Jun Lu, Anup Bhalla, Xiaobin Wang, Allen Chang, Man Sheng Hu, Xiaotian Zhang
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Patent number: 7880223Abstract: A method for manufacturing a transient voltage suppressing (TVS) array substantially following a manufacturing process for manufacturing a vertical semiconductor power device. The method includes a step of opening a plurality of isolation trenches in an epitaxial layer of a first conductivity type in a semiconductor substrate followed by applying a body mask for doping a body region having a second conductivity type between two of the isolation trenches. The method further includes a step of applying an source mask for implanting a plurality of doped regions of the first conductivity type constituting a plurality of diodes wherein the isolation trenches isolating and preventing parasitic PNP or NPN transistor due to a latch-up between the doped regions of different conductivity types.Type: GrantFiled: November 30, 2006Date of Patent: February 1, 2011Assignee: Alpha & Omega Semiconductor, Ltd.Inventor: Madhur Bobde
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Patent number: 7863995Abstract: 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: GrantFiled: April 1, 2008Date of Patent: January 4, 2011Assignee: Alpha & Omega Semiconductor Ltd.Inventors: Moses Ho, Madhur Bobde, Mike Chang, Limin Weng
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Patent number: 7863675Abstract: This invention discloses a new MOSFET device. The MOSFET device has an improved operation characteristic achieved by manufacturing a MOSFET with a higher gate work function by implementing a P-doped gate in an N-MOSFET device. The P-type gate increases the threshold voltage and shifts the C-Vds characteristics. The reduced Cgd thus achieves the purpose of suppressing the shoot through and resolve the difficulties discussed above. Unlike the conventional techniques, the reduction of the capacitance Cgd is achieved without requiring complicated fabrication processes and control of the recess electrode.Type: GrantFiled: March 22, 2008Date of Patent: January 4, 2011Assignee: Alpha & Omega Semiconductor, Ltd.Inventors: Anup Bhalla, Sik K. Lui
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Patent number: 7855422Abstract: A semiconductor device includes a transistor, a capacitor and a resistor wherein the capacitor includes a doped polysilicon layer to function as a bottom conductive layer with a salicide block (SAB) layer as a dielectric layer covered by a Ti/TiN layer as a top conductive layer thus constituting a single polysilicon layer metal-insulator-polysilicon (MIP) structure. While the high sheet rho resistor is also formed on the same single polysilicon layer with differential doping of the polysilicon layer.Type: GrantFiled: May 31, 2006Date of Patent: December 21, 2010Assignee: Alpha & Omega Semiconductor, Ltd.Inventors: YongZhong Hu, Sung-Shan Tai
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Patent number: 7851856Abstract: 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: GrantFiled: December 29, 2008Date of Patent: December 14, 2010Assignee: Alpha & Omega Semiconductor, LtdInventor: François Hébert
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Patent number: 7851286Abstract: This invention discloses a method to form a bottom-source lateral diffusion MOS (BS-LDMOS) device with 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 method includes a step of applying a sinker-channel mask for carrying out a deep sinker multiple energy implant to form a combined sinker-channel region in lower portion of an epitaxial layer to function as a buried source-body contact extending to and contacting a bottom of the substrate functioning as a bottom source electrode.Type: GrantFiled: June 25, 2009Date of Patent: December 14, 2010Assignee: Alpha & Omega Semiconductor, LtdInventor: François Hébert
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Patent number: 7838977Abstract: This invention discloses an electronic package for containing a vertical semiconductor chip that includes a laminated board having a via connector and conductive traces distributed on multiple layers of the laminated board connected to the via connector. The semiconductor chip having at least one electrode connected to the conductive traces for electrically connected to the conductive traces at a different layer on the laminated board and the via connector dissipating heat generated from the vertical semiconductor. A ball grid array (BGA) connected to the via connector functioning as contact at a bottom surface of the package for mounting on electrical terminals disposed on a printed circuit board (PCB) wherein the laminated board having a thermal expansion coefficient in substantially a same range the PCB whereby the BGA having a reliable electrical contact with the electrical terminals.Type: GrantFiled: September 7, 2005Date of Patent: November 23, 2010Assignee: Alpha & Omega Semiconductor, Ltd.Inventors: Ming Sun, Yueh Se Ho
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Patent number: 7829941Abstract: 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: GrantFiled: January 24, 2006Date of Patent: November 9, 2010Assignee: Alpha & Omega Semiconductor, Ltd.Inventors: Yongzhong Hu, Sung-Shan Tai