Patents Assigned to Alpha and Omega Semiconductor, Ltd.
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Publication number: 20090322461Abstract: 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: ApplicationFiled: June 30, 2008Publication date: December 31, 2009Applicant: ALPHA & OMEGA SEMICONDUCTOR, LTD.Inventors: Francois Hebert, Tao Feng, Jun Lu
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Patent number: 7633119Abstract: 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 of the cells constituting an active cell has a source region disposed next to a trenched gate electrically connecting to a gate pad and surrounding the cell. The trenched gate further has a bottom-shielding electrode filled with a gate material disposed below and insulated from the trenched gate. At least one of the cells constituting a source-contacting cell surrounded by the trench with a portion functioning as a source connecting trench is filled with the gate material for electrically connecting between the bottom-shielding electrode and a source metal disposed directly on top of the source connecting trench.Type: GrantFiled: February 17, 2006Date of Patent: December 15, 2009Assignee: Alpha & Omega Semiconductor, LtdInventors: Anup Bhalla, Sik K Lui
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Patent number: 7633135Abstract: 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 an Schottky anode.Type: GrantFiled: July 22, 2007Date of Patent: December 15, 2009Assignee: Alpha & Omega Semiconductor, Ltd.Inventor: François Hébert
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Publication number: 20090294934Abstract: A clip for a semiconductor device package may include two or more separate electrically conductive fingers electrically connected to each other by one or more electrically conductive bridges. A first end of at least finger is adapted for electrical contact with a lead frame. The bridges are adapted to provide electrical connection to a top semiconductor region of a semiconductor device and may also to provide heat dissipation path when a top surface of the fingers is exposed. A semiconductor device package may include the clip along with a semiconductor device and a lead frame. The semiconductor device may have a first and semiconductor regions on top and bottom surfaces respectively. The clip may be electrically connected to the top semiconductor region at the bridges and electrically connected to the lead frame at a first end of at least one of the fingers.Type: ApplicationFiled: May 30, 2008Publication date: December 3, 2009Applicant: ALPHA & OMEGA SEMICONDUCTOR, LTD.Inventors: Lei Shi, Kai Liu, Ming Sun
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Publication number: 20090273328Abstract: 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: ApplicationFiled: May 19, 2009Publication date: November 5, 2009Applicant: ALPHA & OMEGA SEMICONDUCTOR, LTD.Inventor: Yu Cheng Chang
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Patent number: 7602029Abstract: This invention discloses an one time programmable (OTP) memory. The OTP memory includes a first and a second metal oxide semiconductor (MOS) transistors connected in parallel and controlled by a single polysilicon stripe functioning as a gate wherein the OTP memory further includes a drift region for 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. In a preferred embodiment, the first and second MOS transistors are N-MOS transistors disposed in a common P-well and the drift region of the first MOS transistor further comprising a P-drift region.Type: GrantFiled: September 7, 2006Date of Patent: October 13, 2009Assignee: Alpha & Omega Semiconductor, Ltd.Inventor: Shekar Mallikararjunaswamy
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Publication number: 20090250770Abstract: 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: ApplicationFiled: April 7, 2008Publication date: October 8, 2009Applicant: ALPHA & OMEGA SEMICONDUCTOR, LTD.Inventors: Yi Su, Anup Bhalla, Daniel Ng
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Publication number: 20090242973Abstract: A semiconductor device includes a gate electrode, a top source region disposed next to the gate electrode, a drain region disposed below the bottom of the gate electrode, a oxide disposed on top of the source region and the gate electrode, and a doped polysilicon spacer disposed along a sidewall of the source region and a sidewall of the oxide. Methods for manufacturing such device are also disclosed.Type: ApplicationFiled: March 31, 2008Publication date: October 1, 2009Applicant: ALPHA & OMEGA SEMICONDUCTOR, LTD.Inventors: Francois Hebert, Anup Bhalla
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Publication number: 20090194880Abstract: 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: ApplicationFiled: January 31, 2008Publication date: August 6, 2009Applicant: ALPHA & OMEGA SEMICONDUCTOR, LTD.Inventors: Tao Feng, Francois Hebert, Ming Sun, Yueh-Se Ho
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Patent number: 7557554Abstract: 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: September 25, 2007Date of Patent: July 7, 2009Assignee: Alpha & Omega Semiconductor, LtdInventor: Yu Cheng Chang
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Publication number: 20090166621Abstract: 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: ApplicationFiled: March 6, 2009Publication date: July 2, 2009Applicant: ALPHA & OMEGA SEMICONDUCTOR, LTD.Inventors: Tiesheng Li, Yu Wang, Yingying Lou, Anup Bhalla
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Patent number: 7554154Abstract: 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: GrantFiled: July 28, 2006Date of Patent: June 30, 2009Assignee: Alpha Omega Semiconductor, Ltd.Inventor: François Hébert
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Patent number: 7554839Abstract: 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: GrantFiled: September 30, 2006Date of Patent: June 30, 2009Assignee: Alpha & Omega Semiconductor, Ltd.Inventor: Madhur Bobde
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Publication number: 20090160045Abstract: A method for making back-to-front electrical connections in a wafer level chip scale packaging process is disclosed. A wafer containing a plurality of semiconductor chips is mounted on a package substrate. Each semiconductor chip in the plurality includes one or more electrodes on an exposed back side. Scribe lines between two or more adjacent chips on the wafer are removed to form relatively wide gaps. A conductive material is applied to the back side of the semiconductor chips and in the gaps. The conductive material in the gaps between two or more of the chips is then cut through leaving conductive material on the back side and on side walls of the two or more chips. As a result, the conductive material provides an electrical connection from the electrode on the back side of the chip to the front side of the chip.Type: ApplicationFiled: December 21, 2007Publication date: June 25, 2009Applicant: ALPHA & OMEGA SEMICONDUCTOR, LTD.Inventors: Ming Sun, Tao Feng, Francois Hebert, Yueh-Se Ho
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Patent number: 7538997Abstract: 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 31, 2006Date of Patent: May 26, 2009Assignee: Alpha & Omega Semiconductor, Ltd.Inventor: Shekar Mallikararjunaswamy
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Publication number: 20090128968Abstract: A stacked-die package for battery protection is disclosed. The battery protection package includes a power control integrated circuit (IC) stacked on top of integrated dual common-drain metal oxide semiconductor field effect transistors (MOSFETs) or two discrete MOSFETs. The power control IC is either stacked on top of one MOSFET or on top of and overlapping both two MOSFETs.Type: ApplicationFiled: November 21, 2007Publication date: May 21, 2009Applicant: ALPHA & OMEGA SEMICONDUCTOR, LTD.Inventors: Jun Lu, Allen Chang, Xiaotian Zhang
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Patent number: 7535021Abstract: 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: November 1, 2005Date of Patent: May 19, 2009Assignee: Alpha & Omega Semiconductor, Ltd.Inventors: Anup Bhalla, Sik K. Lui, Daniel Ng
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Publication number: 20090114949Abstract: 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: ApplicationFiled: November 1, 2007Publication date: May 7, 2009Applicant: ALPHA & OMEGA SEMICONDUCTOR, LTD.Inventor: Francois Hebert
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Patent number: 7521332Abstract: 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: GrantFiled: March 23, 2007Date of Patent: April 21, 2009Assignee: Alpha & Omega Semiconductor, LtdInventors: Tiesheng Li, Yu Wang, Yingying Lou, Anup Bhalla
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Publication number: 20090079409Abstract: 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: ApplicationFiled: September 25, 2007Publication date: March 26, 2009Applicant: ALPHA & OMEGA SEMICONDUCTOR, LTD.Inventor: Yu Cheng Chang