Patents Assigned to Alpha and Omega Semiconductor, Inc.
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Patent number: 8218276Abstract: This invention discloses an electronic device formed as an integrated circuit (IC) wherein the electronic device further includes a transient voltage suppressing (TVS) circuit for suppressing a transient voltage. The transient voltage suppressing (TVS) circuit includes a Zener diode connected between a ground terminal and a node for triggering a snapback circuit. In one embodiment, this node may be a Vcc terminal. The TVS device further includes a snapback circuit connected in parallel to the Zener diode for conducting a transient voltage current with a snapback current-voltage (I-V) characteristic upon turning on of the snapback circuit And, the TVS device further includes a snapback suppressing circuit connected in series with the snapback circuit for conducting a current with an I-V characteristic complementary to the snapback-IV characteristic for clamping a snapback voltage.Type: GrantFiled: June 30, 2009Date of Patent: July 10, 2012Assignee: Alpha and Omega Semiconductor Inc.Inventor: Shekar Mallikarjunaswamy
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Patent number: 8212329Abstract: A short channel Lateral MOSFET (LMOS) and method are disclosed with interpenetrating drain-body protrusions (IDBP) for reducing channel-on resistance while maintaining high punch-through voltage. The LMOS includes lower device bulk layer; upper source and upper drain region both located atop lower device bulk layer; both upper source and upper drain region are in contact with an intervening upper body region atop lower device bulk layer; both upper drain and upper body region are shaped to form a drain-body interface; the drain-body interface has an IDBP structure with a surface drain protrusion lying atop a buried body protrusion while revealing a top body surface area of the upper body region; gate oxide-gate electrode bi-layer disposed atop the upper body region forming an LMOS with a short channel length defined by the horizontal length of the top body surface area delineated between the upper source region and the upper drain region.Type: GrantFiled: November 6, 2010Date of Patent: July 3, 2012Assignee: Alpha and Omega Semiconductor Inc.Inventors: Shekar Mallikarjunaswamy, Amit Paul
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Patent number: 8193580Abstract: A semiconductor device embodiment includes a substrate, an active gate trench in the substrate, and an asymmetric trench in the substrate. The asymmetric trench has a first trench wall and a second trench wall, the first trench wall is lined with oxide having a first thickness, and the second trench wall is lined with oxide having a second thickness that is different from the first thickness. Another semiconductor device embodiment includes a substrate, an active gate trench in the substrate; and a source polysilicon pickup trench in the substrate. The source polysilicon pickup trench includes a polysilicon electrode, and top surface of the polysilicon electrode is below a bottom of a body region. Another semiconductor device includes a substrate, an active gate trench in the substrate, the active gate trench has a first top gate electrode and a first bottom source electrode, and a gate runner trench comprising a second top gate electrode and a second bottom source electrode.Type: GrantFiled: August 14, 2009Date of Patent: June 5, 2012Assignee: Alpha and Omega Semiconductor, Inc.Inventors: John Chen, Il Kwan Lee, Hong Chang, Wenjun Li, Anup Bhalla, Hamza Yilmaz
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Publication number: 20120129328Abstract: A semiconductor device formed on a semiconductor substrate may include a component formed in a contact trench located in an active cell region. The component may comprise a barrier metal deposited on a bottom and portions of sidewalls of the contact trench and a tungsten plug deposited in a remaining portion of the contact trench. The barrier metal may comprise first and second metal layers. The first metal layer may be proximate to the sidewall and the bottom of the contact trench. The first metal layer may include a nitride. The second metal layer may be between the first metal layer and the tungsten plug and between the tungsten plug and the sidewall. The second metal layer covers portions of the sidewalls of not covered by the first metal layer.Type: ApplicationFiled: January 30, 2012Publication date: May 24, 2012Applicant: ALPHA & OMEGA SEMICONDUCTOR, INC.Inventors: Hong Chang, John Chen, Limin Weng, Wenjun Li
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Patent number: 8183662Abstract: A top-side cooled compact semiconductor package with integrated bypass capacitor is disclosed. The top-side cooled compact semiconductor package includes a circuit substrate with terminal leads, numerous semiconductor dies bonded atop the circuit substrate, numerous elevation-adaptive interconnection plates for bonding and interconnecting top contact areas of the semiconductor dies with the circuit substrate, a first member of the elevation-adaptive interconnection plates has a first flat-top area and a second member of the elevation-adaptive interconnection plates has a second flat-top area in level with the first flat-top area, a bypass capacitor, having two capacitor terminals located at its ends, stacked atop the two interconnection plate members while being bonded thereto via the first flat-top area and the second flat-top area for a reduced interconnection parasitic impedance.Type: GrantFiled: October 14, 2011Date of Patent: May 22, 2012Assignee: Alpha & Omega Semiconductor, Inc.Inventors: François Hébert, Kai Liu
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Patent number: 8178954Abstract: A semiconductor package for power converter application comprises a low-side MOSFET chip and a high-side MOSFET chip stacking one over the other. The semiconductor package may further enclose a capacitor whereas the capacitor may be a discrete component or an integrated component on chip level with the low-side MOSFET. The semiconductor package may further comprise a PIC chip to provide a complete power converter on semiconductor chip assembly package level.Type: GrantFiled: January 26, 2010Date of Patent: May 15, 2012Assignee: Alpha & Omega Semiconductor, Inc.Inventors: Yan Xun Xue, Anup Bhalla, Jun Lu
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Patent number: 8174283Abstract: This invention discloses a method for calibrating a gate resistance measurement of a semiconductor power device that includes a step of forming a RC network on a test area on a semiconductor wafer adjacent to a plurality of semiconductor power chips and measuring a resistance and a capacitance of the RC network to prepare for carrying out a wafer-level measurement calibration of the semiconductor power device. The method further includes a step of connecting a probe card to a set of contact pads on the semiconductor wafer for carrying out the wafer-level measurement calibration followed by performing a gate resistance Rg measurement for the semiconductor power chips.Type: GrantFiled: May 11, 2009Date of Patent: May 8, 2012Assignee: Alpha & Omega Semiconductor, Inc.Inventors: Anup Bhalla, Sik K. Lui, Daniel Ng
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Patent number: 8163601Abstract: A method of making a chip-exposed semiconductor package comprising the steps of: plating a plurality of electrode on a front face of each chip on a wafer; grinding a backside of the wafer and depositing a back metal then separating each chips; mounting the chips with the plating electrodes adhering onto a front face of a plurality of paddle of a leadframe; adhering a tape on the back metal and encapsulating with a molding compound; removing the tape and sawing through the leadframe and the molding compound to form a plurality of packaged semiconductor devices.Type: GrantFiled: September 29, 2010Date of Patent: April 24, 2012Assignee: Alpha & Omega Semiconductor, Inc.Inventors: Yuping Gong, Yan Xun Xue
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Patent number: 8159828Abstract: A power module is proposed to package an electronic system having flip chip power MOSFET devices. The power module includes a front surface cover board and a multi-layer printed circuit laminate bonded thereto. Notably, the front surface of the printed circuit laminate includes recessed pockets each having printed circuit traces atop its floor. Inside the recessed pockets are power MOSFET and other circuit components bonded to the printed circuit traces. As the circuit components are encased inside the power module, it features a low profile, an increased mechanical robustness and EMI/RFI immunity. Additionally, some circuit components can be provided with a front-side bonding layer that is also bonded to the front surface cover board to realize a double-side bonding to the interior of the power module. Methods for making the low profile power module are also described.Type: GrantFiled: February 23, 2007Date of Patent: April 17, 2012Assignee: Alpha & Omega Semiconductor, Inc.Inventors: Ming Sun, Demei Gong
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Patent number: 8148817Abstract: A DC-DC buck converter in multi-die package is proposed having an output inductor, a low-side Schottky diode and a high-side vertical MOSFET controlled by a power regulating controller (PRC). The multi-die package includes a first die pad with the Schottky diode placed there on side by side with the vertical MOSFET. The PRC die is attached atop the first die pad via an insulating die bond. Alternatively, the first die pad is grounded. The vertical MOSFET is a top drain N-channel FET, the substrate of Schottky diode die is its anode. The Schottky diode and the vertical MOSFET are stacked atop the first die pad. The PRC is attached atop the first die pad via a 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: GrantFiled: September 24, 2010Date of Patent: April 3, 2012Assignee: Alpha & Omega Semiconductor, Inc.Inventors: François Hébert, Allen Chang
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Patent number: 8148758Abstract: A high-voltage field-effect device contains an extended drain or “drift” region including an embedded stack of JFET regions separated by intervening layers of the drift region. Each of the JFET regions is filled with material of an opposite conductivity type to that of the drift region, and the floor and ceiling of each JFET region is lined with an oxide layer. When the device is blocking a voltage in the off condition, the semiconductor material inside the JFET regions and in the drift region that separates the JFET regions is depleted. This improves the voltage-blocking ability of the device while conserving chip area. The oxide layer prevents dopant from the JFET regions from diffusing into the drift region.Type: GrantFiled: December 16, 2010Date of Patent: April 3, 2012Assignee: Alpha and Omega Semiconductor Inc.Inventor: Hamza Yilmaz
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Patent number: 8138605Abstract: A semiconductor device formed on a semiconductor substrate may include a component formed in a contact trench located in an active cell region. The component may comprise a barrier metal deposited on a bottom and portions of sidewalls of the contact trench and a tungsten plug deposited in a remaining portion of the contact trench. The barrier metal may comprise first and second metal layers. The first metal layer may be proximate to the sidewall and the bottom of the contact trench. The first metal layer may include a nitride. The second metal layer may be between the first metal layer and the tungsten plug and between the tungsten plug and the sidewall. The second metal layer covers portions of the sidewalls of not covered by the first metal layer.Type: GrantFiled: October 26, 2009Date of Patent: March 20, 2012Assignee: Alpha & Omega Semiconductor, Inc.Inventors: Hong Chang, John Chen, Limin Weng, Wenjun Li
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Patent number: 8098466Abstract: 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: April 26, 2011Date of Patent: January 17, 2012Assignee: Alpha and Omega Semiconductor Inc.Inventor: Shekar Mallikarjunaswamy
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Patent number: 8084304Abstract: A method for preventing gate oxide damage of a trench MOSFET during wafer processing while adding an ESD protection module atop the trench MOSFET includes fabricate numerous trench MOSFETs on a wafer; add a Si3N4 isolation layer, capable of preventing the LTO patterning process from damaging the gate oxide, atop the wafer; add numerous ESD protection modules atop the Si3N4 isolation layer.Type: GrantFiled: May 29, 2010Date of Patent: December 27, 2011Assignee: Alpha & Omega Semiconductor, Inc.Inventors: Mengyu Pan, Zengyi He, Kaiyu Chen
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Patent number: 8076183Abstract: A method is disclosed for attaching an interconnection plate to semiconductor die within leadframe package. A base leadframe is provided with die pad for attaching semiconductor die. An interconnection plate is provided for attachment to the base leadframe and semiconductor die. Add a base registration feature onto base leadframe and a plate registration feature onto interconnection plate with the registration features designed to match each other such that, upon approach of the interconnection plate to base leadframe, the two registration features would engage and guide each other causing concomitant self-aligned attachment of the interconnection plate to base leadframe. Next, the interconnection plate is brought into close approach to base leadframe to engage and lock plate registration feature to base registration feature hence completing attachment of the interconnection plate to semiconductor die and forming a leadframe package.Type: GrantFiled: October 27, 2009Date of Patent: December 13, 2011Assignee: Alpha and Omega Semiconductor, Inc.Inventors: Yan Xun Xue, Jun Lu, Le Shi, Liang Zhao
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Patent number: 8067304Abstract: A method is disclosed for forming a patterned thick metallization atop a semiconductor chip wafer. The method includes fabricating a nearly complete semiconductor chip wafer ready for metallization; depositing a bottom metal layer of sub-thickness TK1 together with its built-in alignment mark using a hot metal process; depositing a top metal layer of sub-thickness TK2 using a cold metal process thus forming a stacked thick metallization of total thickness TK=TK1+TK2; then, use the built-in alignment mark as reference, patterning the stacked thick metallization. A patterned thick metallization is thus formed with the advantages of better metal step coverage owing to the superior step coverage nature of the hot metal process as compared to the cold metal process; and lower alignment error rate owing to the lower alignment signal noise nature of the cold metal process as compared to the hot metal process.Type: GrantFiled: January 20, 2009Date of Patent: November 29, 2011Assignee: Alpha and Omega Semiconductor, Inc.Inventor: Il Kwan Lee
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Patent number: 8062932Abstract: A top-side cooled compact semiconductor package with integrated bypass capacitor is disclosed. The top-side cooled compact semiconductor package includes a circuit substrate with terminal leads, numerous semiconductor dies bonded atop the circuit substrate, numerous elevation-adaptive interconnection plates for bonding and interconnecting top contact areas of the semiconductor dies with the circuit substrate, a first member of the elevation-adaptive interconnection plates has a first flat-top area and a second member of the elevation-adaptive interconnection plates has a second flat-top area in level with the first flat-top area, a bypass capacitor, having two capacitor terminals located at its ends, stacked atop the two interconnection plate members while being bonded thereto via the first flat-top area and the second flat-top area for a reduced interconnection parasitic impedance.Type: GrantFiled: December 8, 2008Date of Patent: November 22, 2011Assignee: Alpha & Omega Semiconductor, Inc.Inventors: François Hébert, Kai Liu
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Publication number: 20110278589Abstract: A gallium nitride based semiconductor diode includes a substrate, a semiconductor body including a first heavily doped GaN layer and a second lightly doped GaN layer. The semiconductor body includes mesas projecting upwardly from a lower surface where each of the mesas includes the second GaN layer and a portion of the first GaN layer. Schottky contacts are formed on the upper surface of the mesas and ohmic contacts are formed on the lower surface of the semiconductor body. An insulating layer is formed over the Schottky and ohmic contacts. Vias are formed in the insulating layer to the Schottky contacts and vias are formed in the semiconductor body to the Ohmic contacts. An anode electrode is formed in a first metal pad in electrical contact with the Schottky contacts. A cathode electrode is formed in a second metal pad in electrical contact with the ohmic contacts.Type: ApplicationFiled: July 26, 2011Publication date: November 17, 2011Applicant: ALPHA & OMEGA SEMICONDUCTOR, INC.Inventor: TingGang Zhu
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Patent number: 8053834Abstract: This invention discloses an inverted field-effect-transistor (iT-FET) semiconductor device that includes a source disposed on a bottom and a drain disposed on a top of a semiconductor substrate. The semiconductor power device further comprises a trench-sidewall gate placed on sidewalls at a lower portion of a vertical trench surrounded by a body region encompassing a source region with a low resistivity body-source structure connected to a bottom source electrode and a drain link region disposed on top of said body regions thus constituting a drift region. The drift region is operated with a floating potential said iT-FET device achieving a self-termination.Type: GrantFiled: December 11, 2009Date of Patent: November 8, 2011Assignee: Alpha & Omega Semiconductor, Inc.Inventor: François Hébert
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Patent number: 8044486Abstract: This invention discloses a bottom-anode Schottky (BAS) diode that includes an anode electrode disposed on a bottom surface of a semiconductor substrate. The bottom-anode Schottky diode further includes a sinker dopant region disposed at a depth in the semiconductor substrate extending substantially to the anode electrode disposed on the bottom surface of the semiconductor and the sinker dopant region covered by a buried Schottky barrier metal functioning as a Schottky anode.Type: GrantFiled: December 11, 2009Date of Patent: October 25, 2011Assignee: Alpha & Omega Semiconductor, Inc.Inventor: François Hébert