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T. Yamashita,
V.S. Basker,
T. Standaert,
C.-C. Yeh,
T. Yamamoto,
K. Maitra,
C.-H. Lin,
J. Faltermeier,
S. Kanakasabapathy,
M. Wang, [......],
M. Colburn,
M. Hane,
D. Mcherron,
V.K. Paruchuri,
B. Doris,
R.J. Miller,
H. Bu,
M. Khare,
J. O'Neill,
E. Leobandung
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ABSTRACT: FinFET devices achieving N/P Ion values of 1250/950 uA/um at 100 nA/um at 1V, 1300/1000 uA/um with self-heating correction, are demonstrated, using a dual work function gate-first process flow at 100 nm gate pitch and 40 nm fin pitch. Ring-oscillator (RO, FO = 3) functionality has been demonstrated, showing excellent Vdd scalability. We have also demonstrated logic scan chain functionality and yield improvement by optimizing the gate stack process. An optimized SIT process has been developed to improve short-channel characteristics in devices with a small number of fins in a narrow active area, which is also critical for manufacturability improvement. Various conformal doping techniques for NFET/PFET are optimized to improve device performance.
VLSI Technology (VLSIT), 2011 Symposium on; 07/2011
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ABSTRACT: This paper reports the architecture and operation of a single-crystal cylindrical rate-integrating gyroscope (CING). The attractive features of the CING include mode stability due to the separation of the wineglass modes from the in-phase-parasitic modes, self-alignment of sensor components, and fabrication. The CING is built using a silicon-on-glass (SOG) process using a (111) Si wafer. It operates at 17.9kHz, has an average Q of 21,800 and a damping-time mismatch of Δτ of 0.7ms along the measured axes, corresponding to a damping-constant mismatch of (Δ1/τ) of 0.0047Hz at a pressure of <;5mTorr. The CING is operated in the whole angle mode with first-generation interface circuitry consisting of software-defined radio.
Solid-State Sensors, Actuators and Microsystems Conference (TRANSDUCERS), 2011 16th International; 07/2011
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ABSTRACT: Here we present a system for digital control of rate-integrating or rate gyroscopes using commercial signal processing hardware. The proposed system, with minimal analog interface hardware and the software and firmware, can seamlessly switch between rate and rate-integrating modes of a rate-integrating capable gyroscope, or operate closed or open loop rate modes for a non-RIG. The control system implements effective amplitude, quadrature and steering control of rate-integrating gyroscopes with a delay of 7ms, and provides a platform for introducing new compensation methods for rate-integrating gyroscopes.
Solid-State Sensors, Actuators and Microsystems Conference (TRANSDUCERS), 2011 16th International; 07/2011
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ABSTRACT: We present a compact model that provides a quick estimation of the stress and mobility patterns around arbitrary configurations of Through-Silicon Via's (TSVs). No separate TCAD simulations are required for these configurations. It estimates nFET and pFET mobility for industry-standard as well as for (100)/<;100>; substrate orientations. As the model provides mobility info in less than 0.1 millisecond/transistor/TSV, it is possible to be used in combination with layouting tools and circuit simulators to optimise layouts of circuits for digital and analog applications. The model has been integrated into the 3D PathFinding flow, for steering 3D IO placement during stack definition.
Design, Automation & Test in Europe Conference & Exhibition (DATE), 2011; 04/2011
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ABSTRACT: In ultrasound dynamic receive beamforming, focusing delays need to be updated for individual focal points, leading to increased hardware complexity. Proposed is a new efficient delay calculation method based on time-sharing bilinear delay interpolation (TS-BDI) to reduce both hardware complexity and focusing delay errors for portable ultrasound systems. The TS-BDI provides 2.5 dB improvement in the signal-to-noise ratio compared to the TS-LDI (linear delay interpolation). In addition, the proposed TS-BDI lowers the hardware complexity in the 64-channel digital dynamic receive beamformer compared to the conventional method, i.e. 36.0 reduction in equivalent gate counts. These results indicate that the proposed TS-BDI method could provide better accuracy in focusing delay calculation with reduced hardware complexity for portable ultrasound systems.
Electronics Letters 02/2011; · 0.96 Impact Factor
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ABSTRACT: In this work we propose an energy-efficient transmission strategy for wireless sensor networks that operate in a strict energy-constrained environment. Our transmission algorithm consists of two components: a binarydecision based transmission and a channel-aware backoff adjustment. In the binary-decision based transmission, decision on whether to transmit or not is absolutely dependent on the current channel conditions. Specifically, transmission is initiated only when the channel quality exceeds a specified threshold, so that unsuccessful transmissions causing a waste of energy are avoided whenever possible. Using the Markov decision process (MDP) formulation we obtain the optimum threshold for successful transmission. A channel-aware backoff adjustment, the second component of our proposal, is introduced to favor nodes with better channel conditions. By intelligently combining these two ingredients our transmission algorithm attempts to maximize energy efficiency. Extensive simulations are performed to verify the performance of our proposal over fading wireless channels. Numerical results show that our transmission algorithm outperforms the existing approaches in terms of energy efficiency, thereby further prolonging the network lifetime
IEEE Transactions on Consumer Electronics 06/2010; · 0.94 Impact Factor
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ABSTRACT: A frequency-reconfigurable antenna for a mobile phone with small volume is proposed. The proposed antenna consists of a planar inverted F-antenna (PIFA) with volume of 4times36times5timesmm<sup>3</sup> and a monopole antenna embedded in the same space. The two antennas are excited by two separate feeds with a common ground plane. A switch is used in the PIFA for frequency-reconfigurable operation. The PIFA can cover either LTE (698-806-MHz) or GSM900 (880-960-MHz) depending on the state of the switch. The monopole antenna can cover either PCS1900 (1.85-1.99-GHz) and m-WiMAX (3.4-3.8-GHz) or WLAN 802.11a (5.15-5.35-GHz) depending on the state of the switch. The antenna gain is in the range of -1.99-0.61-dBi over 700-MHz-2-GHz bands and 2.39-4.62-dBi over the bands higher than 3-GHz. The proposed antenna is shown to have good radiation characteristics.
Electronics Letters 10/2009; · 0.96 Impact Factor
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ABSTRACT: Reverse leakage current characteristics of GaInN/GaN multiple quantum well light-emitting diodes (LEDs) with various chip geometries are examined. The effect of chip geometry on the reverse leakage current is negligible at a low voltage, but becomes apparent at a high voltage. The reverse breakdown voltage of LEDs decreases as the angle of vertex in the chip geometry decreases presumably because of a highly localised electric field strength near the vertex. This suggests that a chip geometry with a rounded vertex is suitable for reliable high-power LEDs.
Electronics Letters 08/2009; · 0.96 Impact Factor
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ABSTRACT: Proposed is an interpolation-free quarter-pixel motion estimation method based on a mathematical model for video encoding. In this method, only three shift operators and four compare operators are required in each horizontal and vertical direction to find a quarter-pixel resolution motion vector. Experimental results show that the proposed method reaches almost the same performance as an interpolation-based full-search for quarter-pixel motion estimation with much less computational complexity.
Electronics Letters 07/2009; · 0.96 Impact Factor
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T. Sowlati,
B. Agarwal, J. Cho,
T. Obkircher,
M. El Said,
J. Vasa,
B. Ramachandran,
M. Kahrizi,
E. Dagher,
Wei-Hong Chen, [......],
S. Tadjpour,
D. Agahi,
D. Rozenblit,
W. Domino,
G. Williams,
N. Damavandi,
S. Wloczysiak,
S. Rajendra,
A. Paff,
T. Valencia
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ABSTRACT: There has been an increased demand for 3G cell phones that support multiple bands of operation and are backward compatible with the 2G/2.5G standard to provide coverage where 3G networks have not yet been fully deployed. The transceiver design for such a handset becomes complicated with the need for separate transceivers for 3G and 2G/2.5G or for multiple inter-stage receive / transmit SAW filters. A single-chip transceiver that operates as a multimode multiband radio and eliminates the inter-stage receive/transmit SAW filters is presented. The transceiver has 7 primary and 4 diversity bands in WCDMA, and quad band in GSM. The transceiver is designed to operate in any of the UTRA bands 1 to 10, with the exception of band 7. It supports HSDPA (Cat 1-12), HSUPA (Cat 1-6), EGPRS (Classes 1-12, 30-39), and compressed mode of EGPRS / WCDMA operation. The transceiver is compliant with 3G DigRF interface 3.09.
Solid-State Circuits Conference - Digest of Technical Papers, 2009. ISSCC 2009. IEEE International; 03/2009
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ABSTRACT: This paper presents a generic vacuum packaging technology for environment-resistant MEMS devices. This packaging approach simultaneously provides low-power oven-controlled thermal environment and vibration isolation using an isolation platform. The oven-controlled structure is thermally isolated from the environment by crab-leg suspensions made out of a 100 mum-thick glass wafer, an anti-radiation shield, and vacuum encapsulation. Performance is evaluated by packaging Pirani gauges and mode-matched tuning fork gyroscopes (M<sup>2</sup>-TFGs). The package has maintained vacuum pressure of ~6 mTorr for ~1 year. A packaged M<sup>2</sup>-TFG shows a high-Q mode-matched operation (Q~65,000) at a constant temperature of -5degC. Allan variance analysis displays an estimated angle random walk (ARW) of 0.012deg/radichr and a bias instability value of 0.55deg/hr at a constant -5degC. Drive frequency stability of 0.22 ppm/degC is obtained using a compensated oven-control approach. Low power consumption of 33 mW for oven-control at 80degC is demonstrated when the environment temperature is -30degC.
Micro Electro Mechanical Systems, 2009. MEMS 2009. IEEE 22nd International Conference on; 03/2009
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ABSTRACT: A system concept, combining orthogonal frequency division multiplexing (OFDM) with fast frequency hopping (FFH), termed FFH/OFDM concept, is illustrated. Data symbols in the frequency domain are mapped to time domain samples by a unitary transformation based on a shuffled version of the well-known inverse discrete Fourier transform. The FFH/OFDM concept shows a promising performance.
Electronics Letters 07/2005; · 0.96 Impact Factor
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W. McFarland,
Won-Joon Choi,
A. Tehrani,
J. Gilbert,
J. Kuskin, J. Cho,
J. Smith,
P. Dua,
D. Breslin,
S. Ng,
Xiaoru Zhang,
Yi-Hsiu Wang,
J. Thomson,
M. Unnikrishnan,
M. Mack,
S. Mendis,
R. Subramanian,
P. Husted,
P. Hanley,
Ning Zhang
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ABSTRACT: A WLAN SoC for video applications handles IEEE 802.11a/b/g and supports PHY data rates to 108 Mbit/s. The SoC implements two chain maximum ratio combining and beamforming. Video features include a jitter removal system and MPEG-TS packet aggregation. Measured results on the 7.2mm×7.2mm IC using a 0.18 μm CMOS process demonstrate throughput improvements in both RX and TX.
Solid-State Circuits Conference, 2005. Digest of Technical Papers. ISSCC. 2005 IEEE International; 03/2005
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ABSTRACT: Hexaferrite thin films of Ba1−xRxFe12−xNixO19 (R=Pr, La) were grown on nonmagnetic garnet substrates by rf sputtering. When deposited at a substrate temperature of 550 °C at rf power density (PDrf) larger than 19 W/cm2, the films were completely crystallized, with the c axis preferentially oriented normal to the film plane. Transmission electron microscopy revealed that the films deposited at low PDrf were amorphous but locally contained microcrystallites several nm in size. On the other hand, the films deposited at PDrf larger than 20 W/cm2 were polycrystalline with a crystallite size as large as 300 nm. Faraday rotation measurements showed that the Ni substitution induced a large negative rotation in the photon energy range of 2.1–2.6 eV. This Ni contribution was predominantly attributed to the crystal-field transition of octahedrally coordinated Ni2+ ions lying in the 2 eV range. No contribution by Pr3+ ions to the Faraday rotation was observed within the photon energy range measured. © 1997 American Institute of Physics.
Journal of Applied Physics 11/1997; 82(10):5126-5131. · 2.17 Impact Factor
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ABSTRACT: Sputtered Ba ferrite films are promising media for magneto‐optical (MO) recording because they have strong perpendicular magnetic anisotropy. However, MO activity of the Ba ferrites is low, which makes the feasibility as a practical medium poor. The MO activity is reported to be prominently enhanced by specific ions such as Bi<sup>3+</sup>, Co<sup>2+</sup>, and light rare earth ions in garnet ferrites, while, in Ba ferrites, the MO enhancement ions except Co<sup>2+</sup> have not yet been known. We have recently found that Ni<sup>2+</sup> substitution also enhances Faraday rotation in the visible region around hν=2.5 eV. In this paper we describe MO properties as well as microstructures of Ba 1-x M x Fe 12-x Ni x O 19 (M=La, Pr, x=0, 0.3, 0.6) films prepared by rf sputtering. The films were deposited on Gd 3 Ga 5 O 12 (GGG) single crystal substrates at substrate temperature (T s ) of 400–600 °C by the conventional rf diode sputtering. When T s ≥550 °C for the incident rf power over 19 W/cm<sup>2</sup>, the films in situ crystallized in Ba–ferrite single phase. They had c‐crystal axis well oriented normal to the film plane. The SEM and TEM observations revealed that the grain size in the films increases from several nm to ∼300 nm with increasing the incident power. The films with larger grains showed higher saturation magnetization and lower coercivity. Faraday rotation of the films was clearly enhanced in the visible around 2.5 eV with increasing Ni<sup>2+</sup> substitution, though they showed rather complicated spectral structure inherent to the Ba ferrites. The enhancement factor of specific Faraday rotation at 2.5 eV was as large as 2×10<sup>4</sup> deg/x, independent of the kind of the rare earth ion substituted for Ba<sup>2+</sup> for charge compensation. This implies that the subst-
itution of the rare earth ion itself enhances no Faraday rotation in Ba ferrites. Thus, the MO enhancement around 2.5 eV may be attributed to the octahedrally coordinated Ni<sup>2+</sup>.
Journal of Applied Physics 06/1993; · 2.17 Impact Factor
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ABSTRACT: Interconnects containing bimodal grain size distributions are known to have lower me-dian times to electromigration-induced
failure (MTTF). However, the deviation in the time to failure (DTTF) in such lines has not been well characterized. We find
that Al-2%Cu-0.3%Cr interconnects with bimodally distributed grain sizes have MTTF’s which are more than an order of magnitude
lower than lines with monomodally distributed small grain sizes. However, the DTTF’s for both types of lines are similar,
and in fact slightly lower for lines with bimodal structures. An activation energy of 0.85 eV was obtained both for lines
with monomodal large grain structures and bimodal grain struc-tures, suggesting that grain boundary diffusion is the controlling
mechanism in both cases. A model based simply on microstructural characteristics,e.g. the distribution of the number of grain boundaries, can explain the lower MTTF’s and DTTF’s for lines with bimodal structures.
The implications of bimodal grain size distributions on the reliability of large numbers of lines are discussed. Also, a new,
convenient graphical tool for illustrating the failure rate of interconnects with lognormally distributed failure times is
presented.
Journal of Electronic Materials 01/1990; 19(11):1207-1212. · 1.47 Impact Factor
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ABSTRACT: Measurements of the median time to failure (MTTF) and deviation in the time to electromigration‐induced failure (DTTF) of Al alloy thin‐film lines are reported. As the ratio of the linewidth to the grain size decreases, MTTF decreases to a minimum and then increases exponentially. DTTF continuously increases. We show that serial and parallel failure unit models can be used to explain the grain size and linewidth dependence of the MTTF and DTTF for interconnects. We further note that extrapolation to low cumulative failures based on serial failure models must be based on knowledge of the failure statistics of individual units.
Applied Physics Letters 07/1989; · 3.84 Impact Factor
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ABSTRACT: INTRODUCTION: Over time, the need for anatomic anterior cruciate ligament (ACL) to restore normal kinematics and postoperative function of the knee has been accepted. The purpose of this study was to compare the sagittal alignment of reconstructed ACL, which is performed between transtibial (TT) technique and accessory anteromedial (AAM) portal technique and between the reconstructed and the normal side in the same patient. In addition, we used the head of a metallic femoral interference screw as a reference to measure the femoral tunnel position. PATIENTS AND METHODS: This was a retrospective study with 15 patients in each group: accessory anteromedial portal technique (n = 15), TT technique (n = 15) and contralateral normal side of each technique group (15 knees per technique). Magnetic resonance images of the ACL sagittal angle and radiographs of the coronal screw angle were used for comparing the two groups. The paired t test was used to compare operated and contralateral normal knee and independent t test was used to compare the TT and the AAM groups. RESULTS: The sagittal angle of ACL of AAM technique (51.6 +/- 3.3 degrees ) was not different from the normal side (50.8 +/- 2.1 degrees ) (P = 0.270), however that of the TT technique (59.9 +/- 5.7 degrees ) was significantly different from the normal side (50.9 +/- 2.4 degrees ) (P < 0.001). The sagittal angle of AAM technique was significantly lower than that of the TT technique (P < 0.001). The coronal angle of the screw to axis of the femur in AAM technique (51.7 +/- 3.8 degrees ) was more horizontal than that of the TT technique (24.4 +/- 8.9 degrees ) (P < 0.001). The center of the screw head of the AAM technique was 30.7 +/- 3.1 % of the Blumensaat line and 39.2 +/- 5.2 % of the condylar height. CONCLUSION: The anatomic sagittal angle of ACL can be achieved using the AAM technique compared with the TT technique. In addition, the angle of the screw in coronal plane was more horizontal using the AAM technique than with use of the TT technique. LEVEL OF EVIDENCE: Level III, diagnostic study.
Arch Orthop Trauma Surg.
