Patents Assigned to Digirad Corporation
  • Publication number: 20070267577
    Abstract: A combined cold plate for RF shield is optimized both for cooling a device and also for shielding it against RF. One embodiment uses a two-part material so that it has improved thermal characteristics from one part and RF shielding characteristics from another part.
    Type: Application
    Filed: May 22, 2007
    Publication date: November 22, 2007
    Applicant: DIGIRAD CORPORATION
    Inventor: Joel Kindem
  • Patent number: 7297927
    Abstract: Ultra-low leakage current backside-illuminated semiconductor photodiode arrays are fabricated using a method of formation of a transparent, conducting bias electrode layer that avoids high-temperature processing of the substrate after the wafer has been gettered. As a consequence, the component of the reverse-bias leakage current associated with strain, crystallographic defects or impurities introduced during elevated temperature processing subsequent to gettering can be kept extremely low. An optically transparent, conductive bias electrode layer, serving as both an optical window and an ohmic backside equipotential contact surface for the photodiodes, is fabricated by etching through the polysilicon gettering layer and a portion of the thickness of heavily-doped crystalline silicon layer formed within, and near the back of, the substrate during the gettering process.
    Type: Grant
    Filed: August 31, 2006
    Date of Patent: November 20, 2007
    Assignee: Digirad Corporation
    Inventors: Lars S. Carlson, Shulai Zhao, John Sheridan, Alan Mollet
  • Patent number: 7256386
    Abstract: Ultra-low leakage current backside-illuminated semiconductor photodiode arrays are fabricated using a method of formation of a transparent, conducting bias electrode layer that avoids high-temperature processing of the substrate after the wafer has been gettered. As a consequence, the component of the reverse-bias leakage current associated with strain, crystallographic defects or impurities introduced during elevated temperature processing subsequent to gettering can be kept extremely low. An optically transparent, conductive bias electrode layer, serving as both an optical window and an ohmic backside equipotential contact surface for the photodiodes, is fabricated by etching through the polysilicon gettering layer and a portion of the thickness of heavily-doped crystalline silicon layer formed within, and near the back of, the substrate during the gettering process.
    Type: Grant
    Filed: May 10, 2004
    Date of Patent: August 14, 2007
    Assignee: Digirad Corporation
    Inventors: Lars S. Carlson, Shulai Zhao, John Sheridan, Alan Mollet
  • Patent number: 7217953
    Abstract: A passive mechanism suppresses injection, into any active guard regions interposed between the edge of a photodiode array chip and the outer photodiode pixels or into the outer pixels themselves, of minority carrier current generated in the physically disrupted region at the edge of the semiconductor die created by cleaving, sawing or otherwise separating the chip from the remainder of the wafer on which the die was fabricated. A thin metallic layer covers all or part of the edge region, thereby creating a Schottky barrier. This barrier generates a depletion region in the adjacent semiconductor material. The depletion region inherently creates an energy band distribution which preferentially accelerates minority carriers generated or near the metal-semiconductor interface towards the metal, thereby suppressing collection of these carriers by any active regions of the guard structure or by the photodiode pixels.
    Type: Grant
    Filed: September 28, 2004
    Date of Patent: May 15, 2007
    Assignee: Digirad Corporation
    Inventor: Lars S. Carlson
  • Patent number: 7164130
    Abstract: Events of interest are detected within a gamma ray detection system. Characteristics of undesired signals, including a multiplicity of events within the signal, a density of events within the signal, and other aspects are determined. The signal is filtered based on its expected characteristics. A signal which does not have the expected characteristics is rejected, and an image is formed that excludes those rejected signals.
    Type: Grant
    Filed: February 18, 2004
    Date of Patent: January 16, 2007
    Assignee: Digirad Corporation
    Inventors: Dan Welsh, Joel Kindem, Michael Gurley, Richard L. Conwell
  • Patent number: 7019783
    Abstract: An embedded power supply for providing a voltage on a detector module within an imaging system provides the required potential to the module from charge stored on an output capacitor. Charge on the capacitor is replenished by injecting, commonly referred to as pumping, current into the capacitor by pulses of current generated by switching mode circuitry. Charge pumping into the capacitor is efficient because energy is stored in low-loss passive components and transferred into the low-loss output capacitor through low-impedance paths. Switching noise of the power supply is eliminated by turning off the charge pumping circuit during periods when such noise would disrupt the operation of the module, for example when the module is reading out image data. The output capacitor is large enough to supply the required voltage to the module for a certain period when the capacitor is not being pumped.
    Type: Grant
    Filed: October 4, 2004
    Date of Patent: March 28, 2006
    Assignee: Digirad Corporation
    Inventors: Joel Kindem, Lars S. Carlson
  • Publication number: 20040206886
    Abstract: Ultra-low leakage current backside-illuminated semiconductor photodiode arrays are fabricated using a method of formation of a transparent, conducting bias electrode layer that avoids high-temperature processing of the substrate after the wafer has been gettered. As a consequence, the component of the reverse-bias leakage current associated with strain, crystallographic defects or impurities introduced during elevated temperature processing subsequent to gettering can be kept extremely low. An optically transparent, conductive bias electrode layer, serving as both an optical window and an ohmic backside equipotential contact surface for the photodiodes, is fabricated by etching through the polysilicon gettering layer and a portion of the thickness of heavily-doped crystalline silicon layer formed within, and near the back of, the substrate during the gettering process.
    Type: Application
    Filed: May 10, 2004
    Publication date: October 21, 2004
    Applicant: Digirad Corporation, a Delaware corporation
    Inventors: Lars S. Carlson, Shulai Zhao, John Sheridan, Alan Mollet
  • Patent number: 6734416
    Abstract: Ultra-low leakage current backside-illuminated semiconductor photodiode arrays are fabricated using a method of formation of a transparent, conducting bias electrode layer that avoids high-temperature processing of the substrate after the wafer has been gettered. As a consequence, the component of the reverse-bias leakage current associated with strain, crystallographic defects or impurities introduced during elevated temperature processing subsequent to gettering can be kept extremely low. An optically transparent, conductive bias electrode layer, serving as both an optical window and an ohmic backside equipotential contact surface for the photodiodes, is fabricated by etching through the polysilicon gettering layer and a portion of the thickness of heavily-doped crystalline silicon layer formed within, and near the back of, the substrate during the gettering process.
    Type: Grant
    Filed: November 15, 2002
    Date of Patent: May 11, 2004
    Assignee: Digirad Corporation
    Inventors: Lars S. Carlson, Shulai Zhao, John Sheridan, Alan Mollet
  • Patent number: 6677182
    Abstract: A passive mechanism suppresses injection, into any active guard regions interposed between the edge of a photodiode array chip and the outer photodiode pixels or into the outer pixels themselves, of minority carrier current generated in the physically disrupted region at the edge of the semiconductor die created by cleaving, sawing or otherwise separating the chip from the remainder of the wafer on which the die was fabricated. A thin metallic layer covers all or part of the edge region, thereby creating a Schottky barrier. This barrier generates a depletion region in the adjacent semiconductor material. The depletion region inherently creates an energy band distribution which preferentially accelerates minority carriers generated or near the metal-semiconductor interface towards the metal, thereby suppressing collection of these carriers by any active regions of the guard structure or by the photodiode pixels.
    Type: Grant
    Filed: April 20, 2001
    Date of Patent: January 13, 2004
    Assignee: Digirad Corporation
    Inventor: Lars S. Carlson
  • Patent number: 6670258
    Abstract: Ultra-low leakage current backside-illuminated semiconductor photodiode arrays are fabricated using a method of formation of a transparent, conducting bias electrode layer that avoids high-temperature processing of the substrate after the wafer has been gettered. As a consequence, the component of the reverse-bias leakage current associated with strain, crystallographic defects or impurities introduced during elevated temperature processing subsequent to gettering can be kept extremely low. An optically transparent, conductive bias electrode layer, serving as both an optical window and an ohmic backside equipotential contact surface for the photodiodes, is fabricated by etching through the polysilicon gettering layer and a portion of the thickness of heavily-doped crystalline silicon layer formed within, and near the back of, the substrate during the gettering process.
    Type: Grant
    Filed: April 20, 2001
    Date of Patent: December 30, 2003
    Assignee: Digirad Corporation
    Inventors: Lars S. Carlson, Shulai Zhao, John Sheridan, Alan Mollet
  • Patent number: 6630735
    Abstract: A semiconductor interconnection device having a semiconductor die, a plurality of epoxy bonds, and an array of insulating islands is disclosed. The semiconductor die has a plurality of conductive contacts. The plurality of epoxy bonds has a metallic substance such as silver. The epoxy bonds are configured to provide interconnection between the semiconductor die and an external structure. The plurality of epoxy bonds is selectively applied to the plurality of conductive contacts on the semiconductor die and corresponding conductive contacts on the external structure. The array of insulating islands is coupled to the plurality of conductive contacts. The islands are configured to prevent migration of the metallic substance from the plurality of epoxy bonds to the semiconductor die through the plurality of conductive contacts.
    Type: Grant
    Filed: April 7, 2000
    Date of Patent: October 7, 2003
    Assignee: Digirad Corporation
    Inventors: Lars S. Carlson, Shulai Zhao
  • Patent number: 6541763
    Abstract: A high-energy photon imaging system including an imaging head, a signal processor, a data acquisition system and an image processing computer. The imaging head includes a detector comprising a plurality of closely-packed detection modules. Each detection module comprises a plurality of detection elements mounted to a circuit carrier. The detection elements produce electrical pulses having amplitudes indicative of the magnitude of radiation absorbed by the detection elements. The circuit carrier includes channels for conditioning and processing the signals generated by corresponding detection elements and for preparing the processed signals for further processing by a signal processor. Each conditioning and processing channel stores the amplitudes of the detection element electrical pulses exceeding a predetermined threshold. The detection modules employ a fall-through circuit which automatically finds only those detection elements that have a stored pulse amplitude exceeding the threshold.
    Type: Grant
    Filed: April 15, 2002
    Date of Patent: April 1, 2003
    Assignee: Digirad Corporation
    Inventors: Clinton L. Lingren, Stanley J. Friesenhahn, Jack F. Butler, F. Patrick Dory, William L. Ashburn, Frank L. Augustine, Boris Apotovsky
  • Patent number: 6504178
    Abstract: A semiconductor imaging device is disclosed. The device includes a substrate having at least first and second surfaces opposing each other, and a circuit layer. The substrate is doped to exhibit a first conductivity type. The substrate includes a conducting layer, a region, and a plurality of doped regions. The conducting layer includes a first type dopants incorporated near the first surface. The region includes a heavily doped area within the substrate near the second surface. The plurality of doped regions includes a second type dopants formed on the second surface. The circuit layer is formed over the second surface to provide gate contacts to and readout circuits for the plurality of doped regions. The readout circuit provides readout of optical signals from pixels.
    Type: Grant
    Filed: April 5, 2001
    Date of Patent: January 7, 2003
    Assignee: Digirad Corporation
    Inventors: Lars S. Carlson, Shulai Zhao, Richard Wilson
  • Publication number: 20020185654
    Abstract: A passive mechanism suppresses injection, into any active guard regions interposed between the edge of a photodiode array chip and the outer photodiode pixels or into the outer pixels themselves, of minority carrier current generated in the physically disrupted region at the edge of the semiconductor die created by cleaving, sawing or otherwise separating the chip from the remainder of the wafer on which the die was fabricated. A thin metallic layer covers all or part of the edge region, thereby creating a Schottky barrier. This barrier generates a depletion region in the adjacent semiconductor material. The depletion region inherently creates an energy band distribution which preferentially accelerates minority carriers generated or near the metal-semiconductor interface towards the metal, thereby suppressing collection of these carriers by any active regions of the guard structure or by the photodiode pixels.
    Type: Application
    Filed: August 7, 2002
    Publication date: December 12, 2002
    Applicant: Digirad Corporation, a Delaware corporation
    Inventor: Lars S. Carlson
  • Publication number: 20020148957
    Abstract: A high-energy photon imaging system including an imaging head, a signal processor, a data acquisition system and an image processing computer. The imaging head includes a detector comprising a plurality of closely-packed detection modules. Each detection module comprises a plurality of detection elements mounted to a circuit carrier. The detection elements produce electrical pulses having amplitudes indicative of the magnitude of radiation absorbed by the detection elements. The circuit carrier includes channels for conditioning and processing the signals generated by corresponding detection elements and for preparing the processed signals for further processing by a signal processor. Each conditioning and processing channel stores the amplitudes of the detection element electrical pulses exceeding a predetermined threshold. The detection modules employ a fall-through circuit which automatically finds only those detection elements that have a stored pulse amplitude exceeding the threshold.
    Type: Application
    Filed: April 15, 2002
    Publication date: October 17, 2002
    Applicant: Digirad Corporation, a Delaware corporation
    Inventors: Clinton L. Lingren, Stanley J. Friesenhahn, Jack F. Butler, F. Patrick Dory, William L. Ashburn, Frank L. Augustine, Boris Apotovsky
  • Publication number: 20020079456
    Abstract: A radiation detector for detecting ionizing radiation. The detector includes a semiconductor having at least two sides. A bias electrode is formed on one side of the semiconductor. A signal electrode is formed on a side of the semiconductor and is used to detect the energy level of the ionizing radiation. A third electrode (the control electrode) is also formed on the semiconductor. The control electrode shares charges induced by the ionizing radiation with the signal electrode, shielding the signal electrode until the charge clouds are close to the signal electrode. The control electrode also alters the electric field within the semiconductor, such that the field guides the charge clouds toward the signal electrode when the clouds closely approach the signal electrode. As a result, signal loss due to trapped charge carriers (i.e., electrons or holes) is minimized, and low-energy tailing is virtually eliminated.
    Type: Application
    Filed: November 13, 2001
    Publication date: June 27, 2002
    Applicant: Digirad Corporation, a California corporation
    Inventors: Clinton L. Lingren, Jack F. Butler, Boris Apotovsky, Richard L. Conwell, F. Patrick Doty, Stanley J. Friesenhahn
  • Publication number: 20010025928
    Abstract: A high-energy photon imaging system including an imaging head, a signal processor, a data acquisition system and an image processing computer. The imaging head includes a detector comprising a plurality of closely-packed detection modules. Each detection module comprises a plurality of detection elements mounted to a circuit carrier. The detection elements produce electrical pulses having amplitudes indicative of the magnitude of radiation absorbed by the detection elements. The circuit carrier includes channels for conditioning and processing the signals generated by corresponding detection elements and for preparing the processed signals for further processing by a signal processor. Each conditioning and processing channel stores the amplitudes of the detection element electrical pulses exceeding a predetermined threshold. The detection modules employ a fall-through circuit which automatically finds only those detection elements that have a stored pulse amplitude exceeding the threshold.
    Type: Application
    Filed: January 30, 2001
    Publication date: October 4, 2001
    Applicant: Digirad Corporation, a Delaware corporation
    Inventors: Clinton L. Lingren, Stanley J. Friesenhahn, Jack F. Butler, F. Patrick Doty, William L. Ashburn, Frank L. Augustine, Boris Apotovsky
  • Patent number: 6194715
    Abstract: A high-energy photon imaging system including an imaging head, a signal processor, a data acquisition system and an image processing computer. The imaging head includes a detector including a plurality of closely-packed detection modules. Each detection module includes a plurality of detection elements mounted to a circuit carrier. The detection elements produce electrical pulses having amplitudes indicative of the magnitude of radiation absorbed by the detection elements. The circuit carrier includes channels for conditioning and processing the signals generated by corresponding detection elements and for preparing the processed signals for further processing by a signal processor. Each conditioning and processing channel stores the amplitudes of the detection element electrical pulses exceeding a predetermined threshold. The detection modules employ a fall-through circuit which automatically finds only those detection elements that have a stored pulse amplitude exceeding the threshold.
    Type: Grant
    Filed: April 5, 1999
    Date of Patent: February 27, 2001
    Assignee: Digirad Corporation
    Inventors: Clinton L. Lingren, Stanley J. Friesenhahn, Jack F. Butler, F. Patrick Doty, William L. Ashburn, Frank L. Augustine, Boris Apotovsky
  • Patent number: 6194726
    Abstract: A radiation detection device for gamma radiation is disclosed having an array of crystals optically positioned adjacent an optional collimator, the crystals emitting visible light upon illumination by the incident gamma radiation. An array of photodetectors is optically positioned adjacent the crystal array on the side of the crystal array opposite that of the collimator. A select photodetector in the photodetector array provides an output signal when the select photodetector is illuminated by the visible light. An integrated circuit having an input from the output signals of said array of photodetectors is used to process and output signals indicative of the intensity and position of the gamma radiation.
    Type: Grant
    Filed: September 22, 1998
    Date of Patent: February 27, 2001
    Assignee: Digirad Corporation
    Inventors: Bo Pi, Timothy C. Collins, Richard L. Conwell
  • Patent number: 6172362
    Abstract: A high-energy photon imaging system including an imaging head, a signal processor, a data acquisition system and an image processing computer. The imaging head includes a detector including a plurality of closely-packed detection modules. Each detection module includes a plurality of detection elements mounted to a circuit carrier. The detection elements produce electrical pulses having amplitudes indicative of the magnitude of radiation absorbed by the detection elements.
    Type: Grant
    Filed: April 5, 1999
    Date of Patent: January 9, 2001
    Assignee: Digirad Corporation
    Inventors: Clinton L. Lingren, Stanley J. Friesenhahn, Jack F. Butler, F. Patrick Doty, William L. Ashburn, Frank L. Augustine, Boris Apotovsky