Patents Assigned to Qspeed Semiconductor, Inc.
  • Patent number: 7746156
    Abstract: A circuit and method for driving a field effect transistor is disclosed. A switching circuit includes a driver device having a signal input, a supply voltage input, and an output. The driver output is coupled to a JFET. A converter couples to the JFET and provides an output of the switching circuit. When enabled, a switching device couples this switching circuit output to the gate of the JFET, thus causing the JFET to be driven into conduction.
    Type: Grant
    Filed: April 16, 2007
    Date of Patent: June 29, 2010
    Assignee: QSpeed Semiconductor Inc.
    Inventors: Harold L. Massie, Kuang Ming Daniel Chang
  • Patent number: 7696540
    Abstract: An apparatus and method for a fast recovery rectifier structure. Specifically, the structure includes a substrate of a first dopant. A first epitaxial layer lightly doped with the first dopant is coupled to the substrate. A first metallization layer is coupled to the first epitaxial layer. A plurality of trenches is recessed into the first epitaxial layer, each of which is coupled to the metallization layer. The device also includes a plurality of wells each doped with a second dopant type, wherein each well is formed beneath and adjacent to a corresponding trench. A plurality of oxide layers is formed on walls and a bottom of a corresponding trench. A plurality of channel regions doped with the first dopant is formed within the first epitaxial layer between two corresponding wells. Each of the plurality of channel regions is more highly doped with the first dopant than the first epitaxial layer.
    Type: Grant
    Filed: December 22, 2006
    Date of Patent: April 13, 2010
    Assignee: Qspeed Semiconductor Inc.
    Inventors: Richard Francis, Yang Yu Fan, Eric Johnson, Hy Hoang
  • Patent number: 7696598
    Abstract: An ultrafast recovery diode. In a first embodiment, a rectifier device comprises a substrate of a first polarity, a lightly doped layer of the first polarity coupled to the substrate and a metallization layer disposed with the lightly doped layer. The ultrafast recovery diode includes a plurality of wells, separated from one another, formed in the lightly doped layer, comprising doping of a second polarity. The plurality of wells connect to the metallization layer. The ultrafast recovery diode further includes a plurality of regions, located between wells of said plurality of wells, more highly doped of the first polarity than the lightly doped layer.
    Type: Grant
    Filed: December 27, 2005
    Date of Patent: April 13, 2010
    Assignee: QSpeed Semiconductor Inc.
    Inventors: Richard Francis, Jian Li, Yang Yu Fan, Eric Johnson
  • Patent number: 7655964
    Abstract: A programmable junction field effect transistor (JFET) with multiple independent gate inputs. A drain, source and a plurality of gate regions for controlling a conductive channel between the source and drain are fabricated in a semiconductor substrate. A first portion the gate regions are coupled to a first gate input and a second portion of the gate regions are coupled to a second gate input. The first and second gate inputs are electrically isolated from each other. The JFET may be programmed by applying a programming voltage to the first gate input and operated by applying a signal to the second gate input.
    Type: Grant
    Filed: March 21, 2005
    Date of Patent: February 2, 2010
    Assignee: Qspeed Semiconductor Inc.
    Inventors: Chong Ming Lin, Ho Yuan Yu
  • Patent number: 7608888
    Abstract: A field effect transistor (FET), in accordance with one embodiment, includes a first semiconductor layer, a first dielectric layer, a second semiconductor layer, a second dielectric layer and a third semiconductor layer. The first dielectric layer may be disposed upon the first semiconductor layer, wherein the first semiconductor layer has a first conductivity type. The second semiconductor layer, having a second conductivity type, may be disposed upon the first dielectric layer. The second dielectric layer may be disposed upon the second semiconductor layer. The third semiconductor layer, having a first conductivity type, may be disposed upon the first semiconductor layer between a first and second portion of the first dielectric layer, a first and second portion of the second semiconductor layer and a first and second portion of the second dielectric layer.
    Type: Grant
    Filed: June 10, 2005
    Date of Patent: October 27, 2009
    Assignee: Qspeed Semiconductor Inc.
    Inventors: Jian Li, Ho-Yuan Yu
  • Patent number: 7452763
    Abstract: A method for fabricating a dual gate structure for JFETs and MESFETs and the associated devices. Trenches are etched in a semiconductor substrate for fabrication of a gate structure for a JFET or MESFET. A sidewall spacer may be formed on the walls of the trenches to adjust the lateral dimension for a first gate. Following the formation of the first gate by implantation or deposition, a buffer region is implanted below the first gate using a complementary dopant and a second sidewall spacer with a thickness that may be the same or greater than the thickness of the first sidewall spacer. Subsequent to the buffer implant, a second gate is implanted beneath the buffer layer using a third sidewall spacer with a greater thickness than the first sidewall spacer.
    Type: Grant
    Filed: February 10, 2004
    Date of Patent: November 18, 2008
    Assignee: Qspeed Semiconductor Inc.
    Inventor: Ho-Yuan Yu
  • Patent number: 7417266
    Abstract: A field effect transistor, in accordance with one embodiment, includes a metal-oxide-semiconductor field effect transistor (MOSFET) having a junction field effect transistor (JFET) embedded as a body diode.
    Type: Grant
    Filed: June 10, 2005
    Date of Patent: August 26, 2008
    Assignee: QSpeed Semiconductor Inc.
    Inventors: Jian Li, Daniel Chang, Ho-Yuan Yu
  • Patent number: 7348826
    Abstract: A composite field effect transistor, in accordance with one embodiment, includes a zener diode, a junction field effect transistor and a metal-oxide-semiconductor field effect transistor. A gate of the junction field effect transistor is coupled to an anode of the zener diode. A cathode of the zener diode is coupled to a gate of the metal-oxide-semiconductor field effect transistor. A drain of the metal-oxide-semiconductor field effect transistor is coupled to a source of the junction field effect transistor.
    Type: Grant
    Filed: March 16, 2006
    Date of Patent: March 25, 2008
    Assignee: QSpeed Semiconductor Inc.
    Inventors: Jonathan Klein, Morris Tsou
  • Patent number: 7268378
    Abstract: A junction field effect transistor (JFET) with a reduced gate capacitance. A gate definition spacer is formed on the wall of an etched trench to establish the lateral extent of an implanted gate region for a JFET. After implant, the gate is annealed. In addition to controlling the final junction geometry and thereby reducing the junction capacitance by establishing the lateral extent of the implanted gate region, the gate definition spacer also limits the available diffusion paths for the implanted dopant species during anneal. Also, the gate definition spacer defines the walls of a second etched trench that is used to remove a portion of the p-n junction, thereby further reducing the junction capacitance.
    Type: Grant
    Filed: May 29, 2002
    Date of Patent: September 11, 2007
    Assignee: Qspeed Semiconductor Inc.
    Inventors: Ho-Yuan Yu, Valentino L. Liva
  • Patent number: 7265398
    Abstract: A method and structure for a composite trench fill for silicon electronic devices. On a planar silicon substrate having a first deposited layer of oxide and a second deposited layer of polysilicon, a trench is etched. Deposition and etch processes using a combination of oxide and polysilicon are used to fabricate a composite trench fill. The trench bottom and a lower portion of the walls are covered with oxide. The remaining portion of the trench volume is filled with polysilicon. The method may be used for junction field effect transistors (JFETs) and metal oxide semiconductor field effect transistors (MOSFETs).
    Type: Grant
    Filed: April 2, 2004
    Date of Patent: September 4, 2007
    Assignee: Qspeed Semiconductor Inc.
    Inventor: Ho-Yuan Yu
  • Patent number: 7262461
    Abstract: JFET and MESFET structures, and processes of making same, for low voltage, high current and high frequency applications. The structures may be used in normally-on (e.g., depletion mode) or normally-off modes. The structures include an oxide layer positioned under the gate region which effectively reduces the junction capacitance (gate to drain) of the structure. For normally off modes, the structures reduce gate current at Vg in forward bias. In one embodiment, a silicide is positioned in part of the gate to reduce gate resistance. The structures are also characterized in that they have a thin gate due to the dipping of the spacer oxide, which can be below 1000 angstroms and this results in fast switching speeds for high frequency applications.
    Type: Grant
    Filed: April 17, 2006
    Date of Patent: August 28, 2007
    Assignee: Qspeed Semiconductor Inc.
    Inventors: Ho-Yuan Yu, Valentino L. Liva
  • Patent number: 7238976
    Abstract: A Schottky barrier rectifier, in accordance with embodiments of the present invention, includes a first conductive layer and a semiconductor. The semiconductor includes a first doped region, a second doped region and a plurality of third doped regions. The second doped region is disposed between the first doped region and the first conductive layer. The plurality of third doped regions are disposed in the second doped region. The first doped region of the semiconductor is heavily doped with a first type of dopant (e.g., phosphorous or arsenic). The second doped region is moderately doped with the first type of dopant. The plurality of third doped regions are moderately to heavily doped with a second type of dopant.
    Type: Grant
    Filed: June 15, 2004
    Date of Patent: July 3, 2007
    Assignee: QSpeed Semiconductor Inc.
    Inventors: Ho-Yuan Yu, Chong-Ming Lin
  • Patent number: 7227242
    Abstract: An etched substrate structure is augmented by conductive material to provide enhanced electrical and/or thermal performance. A semiconductor device substrate comprising active regions defined on a top surface is masked and etched to define a pattern of blind features in a bottom surface of the substrate. A conductive material is then deposited on the surface of the blind features. The replacement of semiconductor material with the conductive material lowers the resistance between the active elements on the top surface and the bottom surface. The blind features may be placed in proximity to parasitic bipolar transistors in order to increase immunity to latchup. During wafer processing, a pattern of grooves aligned opposite to a scribe street pattern may be etched on the wafer back side in order to facilitate the separation of individual devices.
    Type: Grant
    Filed: October 9, 2003
    Date of Patent: June 5, 2007
    Assignee: QSpeed Semiconductor Inc.
    Inventors: Chong Ming Lin, Jay Denning, Ho Yuan Yu
  • Patent number: 7220661
    Abstract: A Schottky barrier rectifier, in accordance with embodiments of the present invention, includes a first conductive layer and a semiconductor. The semiconductor includes a first doped region, a second doped region and a plurality of third doped regions. The second doped region is disposed between the first doped region and the first conductive layer. The plurality of third doped regions are disposed in the second doped region. The first doped region of the semiconductor is heavily doped with a first type of dopant (e.g., phosphorous or arsenic). The second doped region is moderately doped with the first type of dopant. The plurality of third doped regions are moderately to heavily doped with a second type of dopant.
    Type: Grant
    Filed: December 22, 2004
    Date of Patent: May 22, 2007
    Assignee: Qspeed Semiconductor Inc.
    Inventors: Ho-Yuan Yu, Chong-Ming Lin
  • Patent number: 7211845
    Abstract: A multiple doped channel in a multiple doped gate junction field effect transistor. In accordance with a first embodiment of the present invention, a junction field effect transistor (JFET) circuit structure comprises a vertical channel. The vertical channel comprises multiple doping regions. The vertical channel may comprise a first region for enhancement mode operation and a second region for depletion mode operation.
    Type: Grant
    Filed: April 19, 2005
    Date of Patent: May 1, 2007
    Assignee: Qspeed Semiconductor, Inc.
    Inventors: Ho-Yuan Yu, Jian Li