Patents by Inventor Fadi H. Gebara
Fadi H. Gebara 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).
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Publication number: 20120262187Abstract: A method and test circuit provide measurements to accurately characterize threshold voltage changes due to negative bias temperature instability (NBTI) and positive bias temperature instability (PBTI). Both the bias temperature instability recovery profile and/or the bias temperature shifts due to rapid repetitions of stress application can be studied. In order to provide accurate measurements when stresses are applied at intervals on the order of tens of nanoseconds while avoiding unwanted recovery, and/or to achieve recovery profile sampling resolutions in the nanosecond range, multiple delay or ring oscillator frequency measurements are made using a delay line that is formed from delay elements that have delay variation substantially caused only by NBTI or PBTI effects. Devices in the delay elements are stressed, and then the delay line/ring oscillator is operated to measure a threshold voltage change for one or more measurement periods on the order of nanoseconds.Type: ApplicationFiled: June 15, 2012Publication date: October 18, 2012Applicant: International Business Machines CorporationInventors: Fadi H. Gebara, Jerry D. Hayes, John P. Keane, Sani R. Nassif, Jeremy D. Schaub
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Publication number: 20120246494Abstract: A method, system and computer program product for generating device fingerprints and authenticating devices uses initial states of internal storage cells after each of a number multiple power cycles for each of a number of device temperatures to generate a device fingerprint. The device fingerprint may include pairs of expected values for each of the internal storage cells and a corresponding probability that the storage cell will assume the expected value. Storage cells that have expected values varying over the multiple temperatures may be excluded from the fingerprint. A device is authenticated by a similarity algorithm that uses a match of the expected values from a known fingerprint with power-up values from an unknown device, weighting the comparisons by the probability for each cell to compute a similarity measure.Type: ApplicationFiled: May 30, 2012Publication date: September 27, 2012Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATIONInventors: Fadi H. Gebara, Joonsoo Kim, Jeremy D. Schaub, Volker Strumpen
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Publication number: 20120205721Abstract: A design structure tangibly embodied in a machine readable medium for designing, manufacturing, or testing an integrated circuit includes a plurality of bit line structures, a plurality of word line structures intersecting said plurality of bit line structures to form a plurality of cell locations, and a plurality of cells located at said plurality of cell locations, each of said cells being selectively coupled to a corresponding bit line structure under control of a corresponding word line structure, each of said cells comprising a logical storage element having at least a first n-type field effect transistor and at least a first p-type field effect transistor, wherein said at least first n-type field effect transistor is formed with a relatively thick buried oxide layer sized to reduce capacitance of said bit line structures, and said at least first p-type field effect transistor is formed with a relatively thin buried oxide layer.Type: ApplicationFiled: April 18, 2012Publication date: August 16, 2012Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATIONInventors: Ching-Te K. Chuang, Fadi H. Gebara, Keunwoo Kim, Jente Benedict Kuang, Hung C. Ngo
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Patent number: 8229683Abstract: A method, test circuit and test system provide measurements to accurately characterize threshold voltage changes due to negative bias temperature instability (NBTI) and positive bias temperature instability (PBTI). Both the bias temperature instability recovery profile and/or the bias temperature shifts due to rapid repetitions of stress application can be studied. In order to provide accurate measurements when stresses are applied at intervals on the order of tens of nanoseconds while avoiding unwanted recovery, and/or to achieve recovery profile sampling resolutions in the nanosecond range, multiple delay or ring oscillator frequency measurements are made using a delay line that is formed from delay elements that have delay variation substantially caused only by NBTI or PBTI effects. Devices in the delay elements are stressed, and then the delay line/ring oscillator is operated to measure a threshold voltage change for one or more measurement periods on the order of nanoseconds.Type: GrantFiled: December 8, 2010Date of Patent: July 24, 2012Assignee: International Business Machines CorporationInventors: Fadi H. Gebara, Jerry D. Hayes, John P. Keane, Sani R. Nassif, Jeremy D. Schaub
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Patent number: 8217427Abstract: A memory circuit includes a plurality of bit line structures, a plurality of word line structures intersecting the plurality of bit line structures to form a plurality of cell locations; and a plurality of cells located at the plurality of cell locations. Each of the cells is selectively coupled to a corresponding one of the bit line structures under control of a corresponding one of the word line structures, and each of the cells in turn includes a logical storage element having at least a first n-type field effect transistor and at least a first p-type field effect transistor. The at least first n-type field effect transistor is formed with a relatively thick buried oxide layer sized to reduce capacitance of the bit line structures, and the at least first p-type field effect transistor is formed with a relatively thin buried oxide layer.Type: GrantFiled: October 2, 2007Date of Patent: July 10, 2012Assignee: International Business Machines CorporationInventors: Ching-Te K. Chuang, Fadi H. Gebara, Keunwoo Kim, Jente Benedict Kuang, Hung C. Ngo
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Patent number: 8219857Abstract: A method, system and computer program product for generating device fingerprints and authenticating devices uses initial states of internal storage cells after each of a number multiple power cycles for each of a number of device temperatures to generate a device fingerprint. The device fingerprint may include pairs of expected values for each of the internal storage cells and a corresponding probability that the storage cell will assume the expected value. Storage cells that have expected values varying over the multiple temperatures may be excluded from the fingerprint. A device is authenticated by a similarity algorithm that uses a match of the expected values from a known fingerprint with power-up values from an unknown device, weighting the comparisons by the probability for each cell to compute a similarity measure.Type: GrantFiled: June 26, 2008Date of Patent: July 10, 2012Assignee: International Business Machines CorporationInventors: Fadi H. Gebara, Joonsoo Kim, Jeremy D. Schaub, Volker Strumpen
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Patent number: 8164942Abstract: Embedded dynamic random access memory (eDRAM) sense amplifier circuitry in which a bit line connected to each of a first plurality of eDRAM cells is controlled by cell control lines tied to each of the cells. During a READ operation the eDRAM cell releases its charge indicating its digital state. The digital charge propagates through the eDRAM sense amplifier circuitry to a mid-rail amplifier inverter circuit which amplifies the charge and provides it to a latch circuit. The latch circuit, in turn, inverts the charge to correctly represent at its output the logical value stored in the eDRAM cell being read, and returns the charge through the eDRAM sense amplifier circuitry to replenish the eDRAM cell.Type: GrantFiled: February 1, 2010Date of Patent: April 24, 2012Assignee: International Business Machines CorporationInventors: Fadi H. Gebara, Jente B. Kuang, Jayakumaran Sivagnaname, Ivan Vo
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Patent number: 8138820Abstract: A distributed charge pump system uses a delay element and frequency dividers to generate out of phase pump clock signals that drive different charge pumps, to offset peak current clock edges for each charge pump and thereby reduce overall peak power. Clock signal division and phase offset may be extended to multiple levels for further smoothing of the pump clock signal transitions. A dual frequency divider may be used which receives the clock signal and its complement, and generates two divided signals that are 90° out of phase. In an illustrative embodiment the clock generator comprises a variable-frequency clock source, and a voltage regulator senses an output voltage of the charge pumps, generates a reference voltage based on a currently selected frequency of the variable-frequency clock source, and temporarily disables the charge pumps (by turning off local pump clocks) when the output voltage is greater than the reference voltage.Type: GrantFiled: May 5, 2011Date of Patent: March 20, 2012Assignee: International Business Machines CorporationInventors: Fadi H. Gebara, Jente B. Kuang, Abraham Mathews
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Patent number: 8111090Abstract: A comparator apparatus for comparing a first and a second voltage input includes a pair of cross-coupled inverter devices, including a pull up device and a pull down device, with output nodes defined between the pull up and pull down devices. A first switching device is coupled to the first input and a second switching device is coupled to the second input, with control circuitry configured for selective switching between a reset mode and a compare mode. In the reset mode, the first and second voltage inputs are coupled to respective output nodes so as to develop a differential signal thereacross, and the pull down devices in each inverter are isolated from the pull up devices. In the compare mode, the voltage inputs are isolated from the output nodes, and the pull down devices in each inverter are coupled to the pull up devices to latch the output nodes.Type: GrantFiled: January 23, 2009Date of Patent: February 7, 2012Assignee: International Business Machines CorporationInventors: Fadi H. Gebara, Jeremy D. Schaub
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Patent number: 8102194Abstract: A distributed charge pump system uses a delay element and frequency dividers to generate out of phase pump clock signals that drive different charge pumps, to offset peak current clock edges for each charge pump and thereby reduce overall peak power. Clock signal division and phase offset may be extended to multiple levels for further smoothing of the pump clock signal transitions. A dual frequency divider may be used which receives the clock signal and its complement, and generates two divided signals that are 90° out of phase. In an illustrative embodiment the clock generator comprises a variable-frequency clock source, and a voltage regulator senses an output voltage of the charge pumps, generates a reference voltage based on a currently selected frequency of the variable-frequency clock source, and temporarily disables the charge pumps (by turning off local pump clocks) when the output voltage is greater than the reference voltage.Type: GrantFiled: August 20, 2010Date of Patent: January 24, 2012Assignee: International Business Machines CorporationInventors: Fadi H. Gebara, Jente B. Kuang, Abraham Mathews
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Patent number: 8063424Abstract: An embedded photodetector apparatus for a three-dimensional complementary metal oxide semiconductor (CMOS) stacked chip assembly having a CMOS chip and one or more thinned CMOS layers is provided. At least one of the one or more thinned CMOS layers includes an active photodiode area defined within the one or more thinned CMOS layers, the active photodiode area being receptive of an optical signal incident thereon, and the active photodiode area comprising a bulk substrate portion of the thinned CMOS layer. The bulk substrate portion has a diode photodetector formed therein.Type: GrantFiled: November 16, 2009Date of Patent: November 22, 2011Assignee: International Business Machines CorporationInventors: Fadi H. Gebara, Tak H. Ning, Qiqing C. Ouyang, Jeremy D. Schaub
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Publication number: 20110204931Abstract: A distributed charge pump system uses a delay element and frequency dividers to generate out of phase pump clock signals that drive different charge pumps, to offset peak current clock edges for each charge pump and thereby reduce overall peak power. Clock signal division and phase offset may be extended to multiple levels for further smoothing of the pump clock signal transitions. A dual frequency divider may be used which receives the clock signal and its complement, and generates two divided signals that are 90° out of phase. In an illustrative embodiment the clock generator comprises a variable-frequency clock source, and a voltage regulator senses an output voltage of the charge pumps, generates a reference voltage based on a currently selected frequency of the variable-frequency clock source, and temporarily disables the charge pumps (by turning off local pump clocks) when the output voltage is greater than the reference voltage.Type: ApplicationFiled: May 5, 2011Publication date: August 25, 2011Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATIONInventors: Fadi H. Gebara, Jente B. Kuang, Abraham Mathews
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Patent number: 7994845Abstract: A switched-capacitor charge pump comprises a two-phase charging circuit, cross-coupled transistors connected to output nodes of the switched capacitors, and a pump output connected to source terminals of the cross-coupled transistors. The charge pump has side transistors for boosting charge transfer, and gating logic of the side transistors includes level shifters which control connections to the pump output or a reference voltage. Negative and positive charge pump embodiments are provided. The charging circuit utilizes non-overlapping wide and narrow clock signals to generate multiple gating signals. The pump clock circuit preferably provides independent, programmable adjustment of the widths of the wide and narrow clock signals. An override mode can be provided using clamping circuits which shunt the pump output to the second nodes of the switched capacitors.Type: GrantFiled: May 12, 2010Date of Patent: August 9, 2011Assignee: International Business Machines CorporationInventors: Fadi H. Gebara, Jente B. Kuang, Abraham Mathews
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Publication number: 20110188295Abstract: Embedded dynamic random access memory (eDRAM) sense amplifier circuitry in which a bit line connected to each of a first plurality of eDRAM cells is controlled by cell control lines tied to each of the cells. During a READ operation the eDRAM cell releases its charge indicating its digital state. The digital charge propagates through the eDRAM sense amplifier circuitry to a mid-rail amplifier inverter circuit which amplifies the charge and provides it to a latch circuit. The latch circuit, in turn, inverts the charge to correctly represent at its output the logical value stored in the eDRAM cell being read, and returns the charge through the eDRAM sense amplifier circuitry to replenish the eDRAM cell.Type: ApplicationFiled: February 1, 2010Publication date: August 4, 2011Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATIONInventors: Fadi H. Gebara, Jente B. Kuang, Jayakumaran Sivagnaname, Ivan Vo
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Patent number: 7949482Abstract: A method, test circuit and test system provide measurements to accurately characterize threshold voltage changes due to negative bias temperature instability (NBTI) and positive bias temperature instability (PBTI). Both the bias temperature instability recovery profile and/or the bias temperature shifts due to rapid repetitions of stress application can be studied. In order to provide accurate measurements when stresses are applied at intervals on the order of tens of nanoseconds while avoiding unwanted recovery, and/or to achieve recovery profile sampling resolutions in the nanosecond range, multiple delay or ring oscillator frequency measurements are made using a delay line that is formed from delay elements that have delay variation substantially caused only by NBTI or PBTI effects. Devices in the delay elements are stressed, and then the delay line/ring oscillator is operated to measure a threshold voltage change for one or more measurement periods on the order of nanoseconds.Type: GrantFiled: June 19, 2008Date of Patent: May 24, 2011Assignee: International Business Machines CorporationInventors: Fadi H. Gebara, Jerry D. Hayes, John P. Keane, Sani R. Nassif, Jeremy D. Schaub
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Publication number: 20110115004Abstract: An embedded photodetector apparatus for a three-dimensional complementary metal oxide semiconductor (CMOS) stacked chip assembly having a CMOS chip and one or more thinned CMOS layers is provided. At least one of the one or more thinned CMOS layers includes an active photodiode area defined within the one or more thinned CMOS layers, the active photodiode area being receptive of an optical signal incident thereon, and the active photodiode area comprising a bulk substrate portion of the thinned CMOS layer. The bulk substrate portion has a diode photodetector formed therein.Type: ApplicationFiled: November 16, 2009Publication date: May 19, 2011Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATIONInventors: Fadi H. Gebara, Tak H. Ning, Qiqing C. Ouyang, Jeremy D. Schaub
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Patent number: 7930120Abstract: A system and circuit for determining data signal jitter via asynchronous sampling provides a low cost and production-integrable mechanism for measuring data signal jitter. The data signal is edge-detected and sampled by a sampling clock of unrelated frequency the sampled values are collected in a histogram according to a folding of the samples around a timebase. The timebase is determined by sweeping to detect a minimum jitter for the folded data. The histogram for the correct estimated timebase period is representative of the probability density function of the location of data signal edges and the jitter characteristics are determined by the width and shape of the density function peaks. Frequency drift can be corrected by adjusting the timebase used to fold the data across the sample set.Type: GrantFiled: April 15, 2008Date of Patent: April 19, 2011Assignee: International Business Machines CorporationInventors: Hayden C. Cranford, Jr., Fadi H. Gebara, Jeremy D. Schaub
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Publication number: 20110074394Abstract: A method, test circuit and test system provide measurements to accurately characterize threshold voltage changes due to negative bias temperature instability (NBTI) and positive bias temperature instability (PBTI). Both the bias temperature instability recovery profile and/or the bias temperature shifts due to rapid repetitions of stress application can be studied. In order to provide accurate measurements when stresses are applied at intervals on the order of tens of nanoseconds while avoiding unwanted recovery, and/or to achieve recovery profile sampling resolutions in the nanosecond range, multiple delay or ring oscillator frequency measurements are made using a delay line that is formed from delay elements that have delay variation substantially caused only by NBTI or PBTI effects. Devices in the delay elements are stressed, and then the delay line/ring oscillator is operated to measure a threshold voltage change for one or more measurement periods on the order of nanoseconds.Type: ApplicationFiled: December 8, 2010Publication date: March 31, 2011Applicant: International Business Machines CorporationInventors: Fadi H. Gebara, Jerry D. Hayes, John P. Keane, Sani R. Nassif, Jeremy D. Schaub
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Patent number: 7880507Abstract: A circular edge detector on an integrated circuit including a plurality of edge detector cells, each of the plurality of edge detector cells having an input select block operable to receive a data signal and a previous cell signal and to generate a present cell signal, and a state capture block operably connected to receive the present cell signal. The present cell signal of each of the plurality of edge detector cells is provided to a next of the plurality of edge detector cells as the previous cell signal for the next of the plurality of edge detector cells, and the present cell signal from a last edge detector cell is provided to a first edge detector cell as the previous cell signal for the first edge detector cell.Type: GrantFiled: November 19, 2009Date of Patent: February 1, 2011Assignee: International Business Machines CorporationInventors: Jerry C Kao, Jente B Kuang, Alan J Drake, Gary D Carpenter, Fadi H Gebara
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Patent number: 7881135Abstract: A test setup for estimating the critical charge of a circuit under test (CUT) uses a charge injection circuit having a switched capacitor that is selectively connected to a node of the CUT. A voltage measurement circuit measures the voltage at a tap in the charge injection circuit before and after the charge is injected. When the injected charge causes an upset in the logical state of the CUT, the critical charge is calculated as the product of the voltage difference and the known capacitance of the capacitor. In one embodiment, (NMOS drain strike simulation) the amount of charge injected is controlled by a variable pulse width generator gating the switch of the charge injection circuit. In another embodiment (PMOS drain strike simulation) the amount of charge injected is controlled by a variable voltage supply selectively connected to the charge storage node.Type: GrantFiled: February 27, 2007Date of Patent: February 1, 2011Assignee: International Business Machines CorporationInventors: Ethan H. Cannon, Alan J. Drake, Fadi H. Gebara, John P. Keane, AJ Kleinosowski