Patents by Inventor Mohamed N. Darwish

Mohamed N. Darwish has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 8330186
    Abstract: A lateral device includes a gate region connected to a drain region by a drift layer. An insulation region adjoins the drift layer between the gate region and the drain region. Permanent charges are embedded in the insulation region, sufficient to cause inversion in the insulation region.
    Type: Grant
    Filed: April 30, 2009
    Date of Patent: December 11, 2012
    Assignee: MaxPower Semiconductor, Inc.
    Inventors: Mohamed N. Darwish, Amit Paul
  • Patent number: 8330214
    Abstract: The present inventors have realized that manufacturability plays into optimization of power semiconductor devices in some surprising new ways. If the process window is too narrow, the maximum breakdown voltage will not be achieved due to doping variations and the like normally seen in device fabrication. Thus, among other teachings, the present application describes some ways to improve the process margin, for a given breakdown voltage specification, by actually reducing the maximum breakdown voltage. In one class of embodiments, this is done by introducing a vertical gradation in the density of fixed electrostatic charge, or in the background doping of the drift region, or both. Several techniques are disclosed for achieving this.
    Type: Grant
    Filed: May 28, 2010
    Date of Patent: December 11, 2012
    Assignee: MaxPower Semiconductor, Inc.
    Inventors: Amit Paul, Mohamed N. Darwish
  • Patent number: 8319278
    Abstract: Power semiconductor devices in which insulated empty space zones are used for field-shaping regions, in place of dielectric bodies previously used. Optionally permanent charge is added at the interface between the insulated empty space zone and an adjacent semiconductor drift region.
    Type: Grant
    Filed: March 10, 2010
    Date of Patent: November 27, 2012
    Assignee: MaxPower Semiconductor, Inc.
    Inventors: Jun Zeng, Mohamed N. Darwish, Richard A. Blanchard
  • Patent number: 8310006
    Abstract: Devices, structures, and related methods for IGBTs and the like which include a self-aligned series resistance at the source-body junction to avoid latchup. The series resistance is achieved by using a charged dielectric, and/or by using a dielectric which provides a source of dopant atoms of the same conductivity type as the source region, at a sidewall adjacent to the source region.
    Type: Grant
    Filed: September 21, 2010
    Date of Patent: November 13, 2012
    Assignee: MaxPower Semiconductor, Inc.
    Inventors: Richard A. Blanchard, Mohamed N. Darwish, Jun Zeng
  • Patent number: 8310001
    Abstract: A vertical device structure includes a volume of semiconductor material, laterally adjoining a trench having insulating material on sidewalls thereof. A gate electrode within the trench is capacitively coupled through the insulating material to a first portion of the semiconducting material. Some portions of the insulating material contain fixed electrostatic charge in a density high enough to invert a second portion of the semiconductor material when no voltage is applied. The inverted portions can be used as induced source or drain extensions, to assure that parasitic are reduced without increasing on-resistance.
    Type: Grant
    Filed: February 27, 2009
    Date of Patent: November 13, 2012
    Assignee: MaxPower Semiconductor Inc.
    Inventors: Mohamed N. Darwish, Jun Zeng
  • Patent number: 8310007
    Abstract: The present application discloses new approaches to integrated power. Two new classes of structures each provide an integrated phase leg, in a process which can easily be integrated with low-voltage and/or peripheral circuits: in one class of disclosed structures, a lateral PMOS device is combined with an NMOS device which has predominantly vertical current flow. In another class of embodiments, a predominantly vertical n-channel device is used for the low-side switch, in combination with a lateral n-channel device. In either case, the common output node is preferably brought out at a backside contact. This device structure is advantageously used to construct complete power supply and/or voltage conversions circuits on a single chip (perhaps connected to external passive reactances).
    Type: Grant
    Filed: July 12, 2010
    Date of Patent: November 13, 2012
    Assignee: MaxPower Semiconductor Inc.
    Inventors: Mohamed N. Darwish, Jun Zeng
  • Patent number: 8304329
    Abstract: Vertical power devices which include an insulated trench containing insulating material and a gate electrode, and related methods. A body region is positioned so that a voltage bias on the gate electrode will cause an inversion layer in the body region. A layer of permanent charge, at or near the sidewall of the trench, provides charge balancing for the space charge in the depleted semiconductor material during the OFF state. A conductive shield layer is positioned below the gate electrode in the insulating material, and reduces capacitive coupling between the gate and the lower part of the trench. This reduces switching losses. In other embodiments, a planar gate electrode controls horizontal carrier injection into the vertical conduction pathway along the trench, while a shield plate lies over the trench itself to reduce capacitive coupling.
    Type: Grant
    Filed: November 25, 2009
    Date of Patent: November 6, 2012
    Assignee: MaxPower Semiconductor, Inc.
    Inventors: Jun Zeng, Mohamed N. Darwish
  • Patent number: 8294235
    Abstract: A MOSFET switch which has a low surface electric field at an edge termination area, and also has increased breakdown voltage. The MOSFET switch has a new edge termination structure employing an N-P-N sandwich structure. The MOSFET switch also has a polysilicon field plate configuration operative to enhance any spreading of any depletion layer located at an edge of a main PN junction of the N-P-N sandwich structure.
    Type: Grant
    Filed: April 12, 2011
    Date of Patent: October 23, 2012
    Assignee: MaxPower Semiconductor, Inc.
    Inventors: Jun Zeng, Mohamed N. Darwish, Shih-Tzung Su
  • Publication number: 20120261746
    Abstract: Methods and resulting device structures for power trench transistor fabrication, wherein a reachup pillar from the field plate trench is left in place to define the location of a self-aligned contact to the field plate.
    Type: Application
    Filed: March 13, 2012
    Publication date: October 18, 2012
    Applicant: MAXPOWER SEMICONDUCTOR, INC.
    Inventors: Mohamed N. Darwish, Zeng Jun, Richard A. Blanchard
  • Publication number: 20120187473
    Abstract: A MOSFET switch which has a low surface electric field at an edge termination area, and also has increased breakdown voltage. The MOSFET switch has a new edge termination structure employing an N-P-N sandwich structure. The MOSFET switch also has a polysilicon field plate configuration operative to enhance any spreading of any depletion layer located at an edge of a main PN junction of the N-P-N sandwich structure.
    Type: Application
    Filed: April 12, 2011
    Publication date: July 26, 2012
    Applicant: MAXPOWER SEMICONDUCTOR INC.
    Inventors: Jun Zeng, Mohamed N. Darwish, Shih-Tzung Su
  • Publication number: 20120161226
    Abstract: A semiconductor device includes a semiconductor layer of a first conductivity type and a semiconductor layer of a second conductivity type formed thereon. The semiconductor layer of the second conductivity type is characterized by a first thickness. The semiconductor device includes a set of trenches having a predetermined depth and extending into the semiconductor layer of the second conductivity type, thereby defining interfacial regions disposed between the semiconductor layer of the second conductivity type and each of the trenches. The trenches comprises a distal portion consisting essentially of a dielectric material disposed therein and a proximal portion comprising the dielectric material and a gate material disposed interior to the dielectric material in the proximal portion of the trench. The semiconductor device further includes a source region coupled to the semiconductor layer of the second conductivity type.
    Type: Application
    Filed: June 9, 2011
    Publication date: June 28, 2012
    Applicant: MAXPOWER SEMICONDUCTOR INC.
    Inventor: Mohamed N. Darwish
  • Patent number: 8203180
    Abstract: An edge termination structure includes a final dielectric trench containing permanent charge. The final dielectric trench is surrounded by first conductivity type semiconductor material (doped by lateral outdiffusion from the trenches), which in turn is laterally surrounded by second conductivity type semiconductor material.
    Type: Grant
    Filed: May 24, 2011
    Date of Patent: June 19, 2012
    Assignee: MaxPower Semiconductor, Inc.
    Inventors: Mohamed N. Darwish, Amit Paul
  • Publication number: 20120146140
    Abstract: A semiconductor device includes a semiconductor substrate, a source region extending along a top surface of the semiconductor substrate, a drain region extending along the top surface of the semiconductor substrate, and a field shaping region disposed within the semiconductor substrate between the source region and the drain region. A cross-section of the semiconductor substrate extending from the source region to the drain region through the field shaping region includes an insulating region. The semiconductor device also includes an active region disposed within the semiconductor substrate between the source region and the drain region. The active region is disposed adjacent to the field shaping region in a direction perpendicular to the cross-section of the semiconductor substrate extending from the source region to the drain region through the field shaping region.
    Type: Application
    Filed: December 14, 2011
    Publication date: June 14, 2012
    Applicant: Fairchild Semiconductor Corporation
    Inventors: Mohamed N. Darwish, Robert Kuo-Chang Yang
  • Publication number: 20120098055
    Abstract: Power semiconductor devices, and related methods, where majority carrier flow is divided into paralleled flows through two drift regions of opposite conductivity types.
    Type: Application
    Filed: July 5, 2011
    Publication date: April 26, 2012
    Applicant: MaxPower Semiconductor, Inc.
    Inventors: Mohamed N. Darwish, Jun Zeng, Richard A. Blanchard
  • Publication number: 20120043602
    Abstract: Improved MOSFET structures and processes, where multiple polysilicon embedded regions are introduced into the n+ source contact area. A top poly Field Plate is used to shield the electric field from penetrating into the channel, so that a very short channel can be used without jeopardizing the device drain-source leakage current. A bottom poly Field Plate is used to modulate the electric field distribution in the drift region such that a more uniform field distribution can be obtained.
    Type: Application
    Filed: January 11, 2010
    Publication date: February 23, 2012
    Applicant: MaxPower Semiconductor Inc.
    Inventors: Jun Zeng, Mohamed N. Darwish, Richard A. Blanchard
  • Publication number: 20120032258
    Abstract: Improved highly reliable power RFP structures and fabrication and operation processes. The structure includes plurality of localized dopant concentrated zones beneath the trenches of RFPs, either floating or extending and merging with the body layer of the MOSFET or connecting with the source layer through a region of vertical doped region. This local dopant zone decreases the minority carrier injection efficiency of the body diode of the device and alters the electric field distribution during the body diode reverse recovery.
    Type: Application
    Filed: August 18, 2011
    Publication date: February 9, 2012
    Applicant: MAXPOWER SEMICONDUCTOR, INC.
    Inventors: Jun Zeng, Mohamed N. Darwish
  • Patent number: 8080848
    Abstract: According to the present invention, semiconductor device breakdown voltage can be increased by embedding field shaping regions within a drift region of the semiconductor device. A controllable current path extends between two device terminals on the top surface of a planar substrate, and the controllable current path includes the drift region. Each field shaping region includes two or more electrically conductive regions that are electrically insulated from each other, and which are capacitively coupled to each other to form a voltage divider dividing a potential between the first and second terminals. One or more of the electrically conductive regions are isolated from any external electrical contact. Such field shaping regions can provide enhanced electric field uniformity in current-carrying parts of the drift region, thereby increasing device breakdown voltage.
    Type: Grant
    Filed: May 10, 2007
    Date of Patent: December 20, 2011
    Assignee: Fairchild Semiconductor Corporation
    Inventors: Mohamed N. Darwish, Robert Kuo-Chang Yang
  • Patent number: 8076719
    Abstract: Improved highly reliable power RFP structures and fabrication and operation processes. The structure includes plurality of localized dopant concentrated zones beneath the trenches of RFPs, either floating or extending and merging with the body layer of the MOSFET or connecting with the source layer through a region of vertical doped region. This local dopant zone decreases the minority carrier injection efficiency of the body diode of the device and alters the electric field distribution during the body diode reverse recovery.
    Type: Grant
    Filed: February 10, 2009
    Date of Patent: December 13, 2011
    Assignee: MaxPower Semiconductor, Inc.
    Inventors: Jun Zeng, Mohamed N. Darwish
  • Publication number: 20110298043
    Abstract: Improved highly reliable power RFP structures and fabrication and operation processes. The structure includes plurality of localized dopant concentrated zones beneath the trenches of RFPs, either floating or extending and merging with the body layer of the MOSFET or connecting with the source layer through a region of vertical doped region. This local dopant zone decreases the minority carrier injection efficiency of the body diode of the device and alters the electric field distribution during the body diode reverse recovery.
    Type: Application
    Filed: August 1, 2011
    Publication date: December 8, 2011
    Applicant: MAXPOWER SEMICONDUCTOR, INC.
    Inventors: Jun Zeng, Mohamed N. Darwish
  • Patent number: 8058682
    Abstract: A semiconductor structure includes a number of semiconductor regions, a pair of dielectric regions and a pair of terminals. The first and second regions of the structure are respectively coupled to the first and second terminals. The third region of the structure is disposed between the first and second regions. The dielectric regions extend into the third region. A concentration of doping impurities present in the third region and a distance between the dielectric regions define an electrical characteristic of the structure. The electrical characteristic of the structure is independent of the width of the dielectric regions width. The first and second regions are of opposite conductivity types. The structure optionally includes a fourth region that extends into the third region, and surrounds a portion of the pair of dielectric regions. The interface region between the dielectric regions and the fourth region includes intentionally introduced charges.
    Type: Grant
    Filed: January 8, 2008
    Date of Patent: November 15, 2011
    Assignee: MaxPower Semiconductor Inc.
    Inventor: Mohamed N. Darwish