Patents Represented by Attorney, Agent or Law Firm Eugene Shkurko
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Patent number: 6762966Abstract: An on-chip circuit and testing method to quantify a transistor charge transfer performance and charge retention capability of a DRAM cell in a realistic operational environment is described. The method and circuit can be extended to evaluate aging of the cell transfer device due to MOSFET wearout mechanisms that become activate during the charge transfer as well as during storage under operating or burn-in conditions. The on-chip circuit forces and senses a voltage to an individual DRAM storage capacitor allowing the pulse test methodology characterize the individual storage capacitor charge leakage rate and quantify the rate of charge transfer between the bitline and the storage capacitor in the DRAM cell.Type: GrantFiled: January 8, 2003Date of Patent: July 13, 2004Assignee: International Business Machines CorporationInventors: Giuseppe LaRosa, Alvin W. Strong
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Patent number: 6232639Abstract: The preferred embodiment of the present invention overcomes the limitations of the prior art and provides a device and method to increase the latch-up immunity of CMOS devices by forming implants at the well edges. The preferred method uses hybrid resist to form these implants at the edges of the N-wells and/or P-wells. The implants reduce the lifetime of minority carriers in the parasitic transistor, and hence reduce the gain of the parasitic transistor. This reduces the propensity of the CMOS device to latch-up. The preferred embodiment method allows these implants to be formed without requiring additional masking steps over prior art methods. Furthermore, the preferred method for forming the implants results in implants that are self aligned to the edges of the wells.Type: GrantFiled: June 30, 1998Date of Patent: May 15, 2001Assignee: International Business Machines CorporationInventors: Faye D. Baker, Jeffrey S. Brown, Robert J. Gauthier, Jr., Steven J. Holmes, Robert K. Leidy, Edward J. Nowak, Steven H. Voldman
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Patent number: 6210866Abstract: The preferred embodiment provides a method for forming unlinked features when using image enhancement techniques. The preferred method is particularly applicable for use in hybrid resist lithographic processes. The method uses a trimming feature embedded in a substrate. The trimming feature acts as a block during a selective etch. This results in unlinked trenches being formed in the substrate. Thus, the preferred method creates unlinked, separate trenches from the “loops” formed by the hybrid resist or other image enhancement techniques. This allows the preferred method to form a plurality of unlinked features rather than the loops or linked features without requiring additional processing steps.Type: GrantFiled: May 4, 1998Date of Patent: April 3, 2001Assignee: International Business Machines CorporationInventors: Toshiharu Furukawa, Mark C. Hakey, Steven J. Holmes, David V. Horak, Paul A. Rabidoux
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Patent number: 6204532Abstract: According to the present invention, a method for fabricating vertical circuit devices which include a body contact is disclosed. During the fabrication process, the body of a transistor is formed from a pillar of single crystal silicon. The silicon pillar is formed over a butted junction of N+ and P+ diffusions. This fabrication process results in a pillar structure which has an n+ diffusion contacting a portion of the base of the transistor body and a P+ diffusion contacting the remainder of the base of the transistor body. The proportion of N+ and P+ area at the base of the silicon pillar depends on the overlay of the opening to the butted junction. Gate oxide is grown over the entire pillar and a polysilicon gate material is then deposited and etched to form the transistor gate. Metal contact studs are formed, preferably via deposition. After fabrication, the entire surface of the device can be planarized by using any standard Chemical Mechanical Planarization (CMP) process.Type: GrantFiled: October 5, 1999Date of Patent: March 20, 2001Assignee: International Business Machines CorporationInventors: Jeffrey Peter Gambino, Jack Allan Mandelman, Stephen Anthony Parke, Matthew Robert Wordeman
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Patent number: 6194268Abstract: The present invention overcomes the limitations of the prior art to allow for the creation of smaller components for use in logic circuits. The invention provides a new method of defining and forming features on a semiconductor substrate by using a layer of material, referred to as a shadow mandrel layer, to cast a shadow. A trough is etched in the shadow mandrel layer. At least one side of the trough will be used to cast a shadow in the bottom of the trough. A conformally deposited photoresist is used to capture the image of the shadow. The image of the shadow is used to define and form a feature. This allows for the creation of images on the surface of a wafer without the diffraction effects encountered in conventional photolithography. This allows for a reduced device size and increased chip operating speed.Type: GrantFiled: October 30, 1998Date of Patent: February 27, 2001Assignee: International Business Machines CorporationInventors: Toshiharu Furukawa, Mark C. Hakey, Steven J. Holmes, David V. Horak, Paul A. Rabidoux
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Patent number: 5831638Abstract: A graphics display subsystem providing internally timed time-varying properties of display attributes is provided. The graphics display subsystem comprises a display device for displaying consecutive image frames of pixels having a variable display property, and a circuit for transferring image frames to the display device. One or more pixels are selected when a display attribute associated with the one or more pixels is set in an attribute table. The circuit varies, during a selected time interval, the display property of the selected pixels being displayed on the display device. In preferred embodiments, the variable display property is either a stereo image display, an image brightness control, or an image-blending control.Type: GrantFiled: March 8, 1996Date of Patent: November 3, 1998Assignee: International Business Machines CorporationInventors: Roderick Michael Peters West, Edward Kelley Evans
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Patent number: 5784632Abstract: A massively parallel processor apparatus having an instruction set architecture for each of the N.sup.2 the PEs of the structure. The apparatus which we prefer will have a PE structure consisting of PEs that contain instruction and data storage units, receive instructions and data, and execute instructions. The N.sup.2 structure should contain "N" communicating ALU trees, "N" programmable root tree processor units, and an arrangement for communicating both instructions, data, and the root tree processor outputs back to the input processing elements by means of the communicating ALU trees. The apparatus can be structured as a bit-serial or word parallel system. The preferred structure contains N.sup.2 PEs, identified as PE.sub.column,row, in a N root tree processor system, placed in the form of a N by N processor array that has been folded along the diagonal and made up of diagonal cells and general cells. The Diagonal-Cells are comprised of a single processing element identified as PE.sub.Type: GrantFiled: March 30, 1995Date of Patent: July 21, 1998Assignee: International Business Machines CorporationInventors: Gerald George Pechanek, Stamatis Vassiliadis, Jose Guadalupe Delgado-Frias
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Patent number: 5666118Abstract: A method of self calibration for a segmented digital-to-analog converter is provided. The segmented digital-to-analog converter converts a digital input code to an analog output consisting of an analog output step and an analog calibration factor. The method comprises the step of determining a trim value for each segment of a segmented DAC. The method continues by storing the trim values in memory. Then, the trim values for a plurality of segments preselected to be enabled by a given digital input signal are summed, thereby producing a digital calibration factor associated with each given digital input signal. Last, storing each digital calibration factor in memory at an address corresponding to the associated digital input signal.Type: GrantFiled: July 30, 1996Date of Patent: September 9, 1997Assignee: International Business Machines CorporationInventor: John Edwin Gersbach
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Patent number: 5649150Abstract: A scannable LIFO register stack in which registers are arranged in a stack with each register having a number of bit locations. Each register is in communication with an adjacent register located above and below it. In particular, each bit location in a register within the stack located between the top and the bottom register is in communication with a corresponding bit location in an adjacent register located above the register and a corresponding bit location in an adjacent register located below the register. Except for the last bit, each bit location in the top register has a connection to an offset bit location in the bottom register. Shifting a bit of data from a bit location in the top register to the offset bit location in the bottom register results in the bit being shifted to the right by one bit location according to the present invention. The last bit location in the top register has an output that is used as a scan output.Type: GrantFiled: April 12, 1995Date of Patent: July 15, 1997Assignee: International Business Machines CorporationInventor: Mark Eric Pedersen