Patents by Inventor Fan Chu

Fan Chu 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).

  • Publication number: 20060098470
    Abstract: A ferroelectric reference circuit generates a reference voltage proportional to (P+U)/2 and is automatically centered between the bit line voltages corresponding to the P term and the U term across wide temperature and voltage ranges. To avoid fatiguing the reference ferroelectric capacitors generating (P+U)/2, the reference voltage is refreshed once every millisecond. To eliminate the variation of the reference voltage due to the leakage in the ferroelectric capacitors during this period of time, the reference voltage generated from the reference ferroelectric capacitors is digitized when it is refreshed. The digital value is fixed and converted to an analog value which is then fed into sense amplifiers for resolving the data states. The reference voltage is automatically at the center of the switching (P) and non-switching (U) signals and therefore the signal margin is maximized.
    Type: Application
    Filed: November 9, 2004
    Publication date: May 11, 2006
    Inventors: Shan Sun, Xiao-Hong Du, Fan Chu, Bob Sommervold
  • Patent number: 6987684
    Abstract: Search engine devices include a content addressable memory (CAM) core having a plurality of CAM array blocks therein and a control circuit that is electrically coupled to the CAM core. The control circuit is configured to support internal error detection and correction operations using modified Hamming code words. These operations are performed without significant impact on the compare bandwidth of the search engine device, even when operations to read entries from the CAM core are performed as foreground operations that may block concurrent search operations. The control circuit may perform the error detection and correction operations by issuing multiple read instructions. These instructions include a first instruction (e.g., error check instruction) to read at least a first entry into the CAM core for the purpose of error detection and then, in response to detecting the first entry as erroneous, issuing a second instruction to read the first entry from the CAM core.
    Type: Grant
    Filed: December 17, 2003
    Date of Patent: January 17, 2006
    Assignee: Integrated Device Technology, Inc.
    Inventors: Kenneth Branth, Kee Park, Scott Yu-Fan Chu, Thomas Diede
  • Patent number: 6972978
    Abstract: A CAM array block is configured to perform a search operation in a staged segment-to-segment manner using a plurality of hybrid comparands that are pipelined into the CAM array block during consecutive stages of the search operation. These hybrid comparands include at least a virtual sector field and a data field. The CAM array block is also responsive to a segment address, which identifies an active segment of CAM cells in said CAM array block. The CAM array block may include a CAM array and a global mask cell sub-array that is electrically coupled to the CAM array. This global mask cell sub-array may be responsive to the segment address and a mode select signal. A bit/data line control circuit is also provided. The bit/data line control circuit is electrically coupled to the CAM array by bit lines and data lines and has inputs that are responsive to signals generated by the global mask cell sub-array. The device may also include an address translation unit that is responsive to an input address.
    Type: Grant
    Filed: September 16, 2003
    Date of Patent: December 6, 2005
    Assignee: Integrated Device Technology, Inc.
    Inventors: Michael Miller, Bertan Tezcan, Kee Park, Scott Yu-Fan Chu
  • Patent number: 6967856
    Abstract: CAM devices include a segmented CAM array that is configured to support a long word search operation (e.g., x8N search) as a plurality of overlapping segment-to-segment search operations that are each performed across different rows within a group of rows in the CAM array and staggered in time relative to one another. To provide enhanced soft error immunity, these CAM devices may also include a CAM array having a row of lateral XY TCAM cells therein that are arranged in a repeating low-even, low-odd, high-even, high-odd sequence, where “low” and “high” represent the first and second halves of a CAM entry. Methods of operating a CAM device may include staggering the timing of overlapping segment-to-segment search operations across different rows within a CAM array using force-to-miss control signals to establish miss conditions on match lines of rows that are not to participate in a respective ones of the segment-to-segment search operations.
    Type: Grant
    Filed: November 4, 2003
    Date of Patent: November 22, 2005
    Assignee: Integrated Device Technology, Inc.
    Inventors: Kee Park, Scott Yu-Fan Chu
  • Patent number: 6965519
    Abstract: Segmented CAM arrays are provided with dual-capture match line signal repeaters that support high speed pipelined search operations. A dual-capture match line signal repeater may extend between xR and xS segments of CAM cells within a respective row. This repeater provides high speed operation by quickly accessing the state (match or miss) of a match line segment when a corresponding segment of CAM cells connected to the match line segment undergo a respective stage of a pipelined search operation. If the match line segment is initially assessed as having a match signal thereon, then that match signal is passed to a next higher match line segment within the same row and a next stage search operation is commenced.
    Type: Grant
    Filed: June 18, 2003
    Date of Patent: November 15, 2005
    Assignee: Integrated Device Technology, Inc.
    Inventors: Kee Park, Scott Yu-Fan Chu
  • Patent number: 6964873
    Abstract: A method of fabricating a semiconductor device having a ferroelectric capacitor includes the steps of forming a lower electrode layer of the ferroelectric capacitor on an insulation film covering an active device element, forming a ferroelectric film on the lower electrode layer as a capacitor insulation film, crystallizing the ferroelectric film by applying a thermal annealing process in an atmosphere containing a non-oxidizing gas and an oxidizing gas, and forming an upper electrode layer on the ferroelectric film.
    Type: Grant
    Filed: April 17, 2000
    Date of Patent: November 15, 2005
    Assignee: Fujitsu Limited
    Inventors: Katsuyoshi Matsuura, Mari Tani, Yoshimasa Horii, Fan Chu, Glen R. Fox, Brian Eastep
  • Patent number: 6937491
    Abstract: Content addressable memory (CAM) devices use both hard and soft priority techniques to allocate entries of different priority therein. The priorities of multiple CAM array blocks within the CAM device may be programmed before or as entries are loaded therein and may be reprogrammed during operation as the allocation of entries within the CAM device changes. The allocation of entries may change in response to additions or deletions of entries or as entries are reprioritized. The CAM devices include preferred priority resolution circuits that can resolve competing soft and hard priorities between multiple hit signals that are generated in response to a search operation. Such hit signals may be active to reflect the presence of at least one matching entry within a CAM array block. The resolution of which active hit signal has the highest overall priority among many can be used to facilitate the identification of the location (e.g.
    Type: Grant
    Filed: October 2, 2002
    Date of Patent: August 30, 2005
    Assignee: Integrated Device Technology, Inc.
    Inventors: Kee Park, Scott Yu-Fan Chu
  • Patent number: 6887716
    Abstract: A method for fabrication of ferroelectric capacitor elements of an integrated circuit includes steps of deposition of an electrically conductive bottom electrode layer, preferably made of a noble metal. The bottom electrode is covered with a layer of ferroelectric dielectric material. The ferroelectric dielectric is annealed with a first anneal prior to depositing a second electrode layer comprising a noble metal oxide. Deposition of the electrically conductive top electrode layer is followed by annealing the layer of ferroelectric dielectric material and the top electrode layer with a second anneal. The first and the second anneal are performed by rapid thermal annealing.
    Type: Grant
    Filed: December 20, 2000
    Date of Patent: May 3, 2005
    Assignee: Fujitsu Limited
    Inventors: Glen Fox, Fan Chu, Brian Eastep, Tomohiro Takamatsu, Yoshimasa Horii, Ko Nakamura
  • Patent number: 6879532
    Abstract: Content addressable memory (CAM) devices include at least one CAM array that is configured to identify at least one match between a new search word and entries therein by performing a staged compare operation that conserves bit line power by initially floating at least some of a plurality of bit lines in said CAM array and then driving the at least some of a plurality of bit lines with second bits of the new search word in response to detecting at least one partial match between first bits of the new search word and the entries in said CAM array.
    Type: Grant
    Filed: September 3, 2004
    Date of Patent: April 12, 2005
    Assignee: Integrated Device Technology, Inc.
    Inventors: Robert J. Proebsting, Scott Yu-Fan Chu, Kee Park
  • Patent number: 6839256
    Abstract: Content addressable memory (CAM) devices achieve high integration by utilizing one or more CAM arrays that are each partitioned by rows into a CAM cell sub-array and a dedicated mask cell sub-array. Each row of mask cells within the mask cell sub-array can be selectively read during one search operation and then used to globally mask one or more columns of the CAM cell sub-array during a following search operation. Mask assertion circuitry is provided to couple a respective mask cell sub-array to a bit/data line control circuit that drives bit and/or data lines to the CAM cell sub-array during read, write and search operations. The mask cell sub-array and CAM cell sub-array may be segmented arrays that support pipelined search, write and read mask operations.
    Type: Grant
    Filed: March 11, 2003
    Date of Patent: January 4, 2005
    Assignee: Integrated Device Technology, Inc.
    Inventors: Robert J. Proebsting, Kee Park, Scott Yu-Fan Chu
  • Patent number: 6829153
    Abstract: Content addressable memory (CAM) devices according to embodiments of the present invention conserve match line and bit line power when CAM array blocks therein are searched. These CAM array blocks are searched in a pipelined segment-to-segment manner to increase search speed. The pipelined search operations may also be interleaved with write and read operations in an efficient manner that reduces the occurrence of pipeline bubbles.
    Type: Grant
    Filed: July 18, 2003
    Date of Patent: December 7, 2004
    Assignee: Integrated Device Technology, Inc.
    Inventors: Kee Park, Scott Yu-Fan Chu
  • Patent number: 6804134
    Abstract: Content addressable memory (CAM) devices include at least one CAM array that is configured to identify at least one match between a new search word and entries therein by performing a staged compare operation that conserves bit line power by initially floating at least some of a plurality of bit lines in said CAM array and then driving the at least some of a plurality of bit lines with second bits of the new search word in response to detecting at least one partial match between first bits of the new search word and the entries in said CAM array.
    Type: Grant
    Filed: April 9, 2003
    Date of Patent: October 12, 2004
    Assignee: Integrated Device Technology, Inc.
    Inventors: Robert J. Proebsting, Scott Yu-Fan Chu, Kee Park
  • Patent number: 6777287
    Abstract: A ferroelectric random access memory has a ferroelectric capacitor formed of a stacking of a lower electrode, a PZT film and an upper electrode of SrRuO3, wherein the PZT film includes pinholes, with a pinhole density of about 17 &mgr;m2 or less.
    Type: Grant
    Filed: May 23, 2003
    Date of Patent: August 17, 2004
    Assignee: Fujitsu Limited
    Inventors: Soichiro Ozawa, Shan Sun, Hideyuki Noshiro, George Hickert, Katsuyoshi Matsuura, Fan Chu, Takeyasu Saito
  • Patent number: 6775168
    Abstract: Content addressable memory (CAM) devices include a first match line segment associated with a first row of CAM cells within a CAM array and an inverter having an input electrically coupled to the first match line segment. A match line precharge support circuit is provided. The match line precharge support circuit includes a first PMOS transistor having a gate terminal electrically coupled to an output of the inverter, a first current carrying terminal that is electrically coupled to the first match line segment and a second current carrying terminal that is electrically coupled to a power supply line.
    Type: Grant
    Filed: July 18, 2003
    Date of Patent: August 10, 2004
    Assignee: Integrated Device Technology, Inc.
    Inventors: Kee Park, Scott Yu-Fan Chu
  • Patent number: 6760242
    Abstract: Content addressable memory (CAM) devices according to embodiments of the present invention conserve match line and bit line power when CAM array blocks therein are searched. These CAM array blocks are searched in a pipelined segment-to-segment manner to increase search speed. The pipelined search operations may also be interleaved with write and read operations in an efficient manner that reduces the occurrence of pipeline bubbles.
    Type: Grant
    Filed: December 18, 2002
    Date of Patent: July 6, 2004
    Assignee: Integrated Device Technology, Inc.
    Inventors: Kee Park, Scott Yu-Fan Chu
  • Publication number: 20040015652
    Abstract: Content addressable memory (CAM) devices use both hard and soft priority techniques to allocate entries of different priority therein. The priorities of multiple CAM array blocks within the CAM device may be programmed before or as entries are loaded therein and may be reprogrammed during operation as the allocation of entries within the CAM device changes. The allocation of entries may change in response to additions or deletions of entries or as entries are reprioritized. The CAM devices include preferred priority resolution circuits that can resolve competing soft and hard priorities between multiple hit signals that are generated in response to a search operation. Such hit signals may be active to reflect the presence of at least one matching entry within a CAM array block. The resolution of which active hit signal has the highest overall priority among many can be used to facilitate the identification of the location (e.g.
    Type: Application
    Filed: October 2, 2002
    Publication date: January 22, 2004
    Inventors: Kee Park, Scott Yu-Fan Chu
  • Publication number: 20040012989
    Abstract: Content addressable memory (CAM) devices use both hard and soft priority techniques to allocate entries of different priority therein. The priorities of multiple CAM array blocks within the CAM device may be programmed before or as entries are loaded therein and may be reprogrammed during operation as the allocation of entries within the CAM device changes. The allocation of entries may change in response to additions or deletions of entries or as entries are reprioritized. The CAM devices include preferred priority resolution circuits that can resolve competing soft and hard priorities between multiple hit signals that are generated in response to a search operation. Such hit signals may be active to reflect the presence of at least one matching entry within a CAM array block. The resolution of which active hit signal has the highest overall priority among many can be used to facilitate the identification of the location (e.g.
    Type: Application
    Filed: October 2, 2002
    Publication date: January 22, 2004
    Inventors: Kee Park, Scott Yu-Fan Chu
  • Publication number: 20030205743
    Abstract: A ferroelectric random access memory has a ferroelectric capacitor formed of a stacking of a lower electrode, a PZT film and an upper electrode of SrRuO3, wherein the PZT film includes pinholes, with a pinhole density of about 17 &mgr;m2 or less.
    Type: Application
    Filed: May 23, 2003
    Publication date: November 6, 2003
    Inventors: Soichiro Ozawa, Shan Sun, Hideyuki Noshiro, George Hickert, Katsuyoshi Matsuura, Fan Chu, Takeyasu Saito
  • Patent number: 6627930
    Abstract: A ferroelectric thin film capacitor and a method for producing the same wherein the capacitor dielectric includes multi-layered crystallographic textures. An integrated circuit device, such as a non-volatile memory device, includes at least one capacitor having a top and bottom electrode thereof and a ferroelectric dielectric layer therebetween. The ferroelectric dielectric layer comprises a first ferroelectric layer having a first crystallographic texture forming a main body of the dielectric layer and a second ferroelectric layer having a second differing crystallographic texture forming an interface layer between the main body and one of the top and bottom electrodes.
    Type: Grant
    Filed: March 14, 2000
    Date of Patent: September 30, 2003
    Assignee: Fujitsu Limited
    Inventors: Glen Fox, Fan Chu, Brian Eastep, Shan Sun
  • Patent number: 6617626
    Abstract: A ferroelectric random access memory has a ferroelectric capacitor formed of a stacking of a lower electrode, a PZT film and an upper electrode of SrRuO3, wherein the PZT film includes pinholes, with a pinhole density of about 17/&mgr;m2 or less.
    Type: Grant
    Filed: February 28, 2001
    Date of Patent: September 9, 2003
    Assignee: Fujitsu Limited
    Inventors: Soichiro Ozawa, Shan Sun, Hideyuki Noshiro, George Hickert, Katsuyoshi Matsuura, Fan Chu, Takeyasu Saito