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Articles 1 - 30 of 44
Full-Text Articles in Engineering
Stochastic Distributed Control For Arbitrarily Connected Microgrid Clusters, Maryam Khanbaghi, Aleksandar Zečević
Stochastic Distributed Control For Arbitrarily Connected Microgrid Clusters, Maryam Khanbaghi, Aleksandar Zečević
Electrical and Computer Engineering
Due to the success of single microgrids, the coming years are likely to see a transformation of the current electric power system to a multiple microgrid network. Despite its obvious promise, however, this paradigm still faces many challenges, particularly when it comes to the control and coordination of energy exchanges between subsystems. In view of that, in this paper we propose an optimal stochastic control strategy in which microgrids are modeled as stochastic hybrid dynamic systems. The optimal control is based on the jump linear theory and is used as a means to maximize energy storage and the utilization of …
A Parallelizable Algorithm For Stabilizing Large Sparse Linear Systems With Uncertain Interconnections, Aleksandar Zečević, Maryam Khanbaghi
A Parallelizable Algorithm For Stabilizing Large Sparse Linear Systems With Uncertain Interconnections, Aleksandar Zečević, Maryam Khanbaghi
Electrical and Computer Engineering
This paper proposes a new method for permuting sparse matrices into an upper block triangular from. The algorithm is highly parallelizable, which makes it suitable for large-scale systems with uncertain interconnection patterns. In such cases, the proposed decomposition can be used to develop flexible decentralized control strategies that produce a different gain matrix whenever the configuration changes. Applications to interconnected microgrids and supply and demand networks are provided to illustrate the versatility of the proposed approach.
Optimal Power And Frequency Control Of Microgrid Cluster With Mixed Loads, Saleh Dinkhah, Johana Salazar Cuellar, Maryam Khanbaghi
Optimal Power And Frequency Control Of Microgrid Cluster With Mixed Loads, Saleh Dinkhah, Johana Salazar Cuellar, Maryam Khanbaghi
Electrical and Computer Engineering
In recent years, voltage and frequency regulation issues have been extensively discussed for the microgrid clusters (MGCs), as the high penetration of renewable energy resources (RES) might affect the continuous operation of the microgrid (MG). Furthermore, to enhance the MGC’s operation reliability, stability concerns need to be addressed. In this study, a residential MGC connected to a commercial MGC has been considered. A novel control scheme that combines both droop control and virtual inertia control is proposed. This control strategy relies on online measurements, and it can be adapted to different situations. At each iteration, the damping coefficient and droop …
Carbon Nanotube-On-Graphene Heterostructures, Yu Zheng, Dongmeng Li, Zubair Ahmed, Jeongwon Park, Changjian Zhou, Cary Y. Yang
Carbon Nanotube-On-Graphene Heterostructures, Yu Zheng, Dongmeng Li, Zubair Ahmed, Jeongwon Park, Changjian Zhou, Cary Y. Yang
Electrical and Computer Engineering
This paper presents a brief review of experimental and theoretical studies on a three-dimensional heterostructure consisting of vertical carbon nanotubes (CNTs) connected perpendicularly to a graphene layer. This structure can serve as a potential building block for an all-carbon network in energy storage devices and on-chip interconnects. The review highlights reported works on the fabrication and characterization of such a heterostructure, with focus on the effect of the CNT-graphene interface on electrical conduction. While a direct comparison between experiment and theory is not possible at this time, a brief survey of theoretical efforts based on atomic cluster models nonetheless reveals …
Jump Linear Quadratic Control For Microgrids With Commercial Loads, Maryam Khanbaghi, Aleksandar Zečević
Jump Linear Quadratic Control For Microgrids With Commercial Loads, Maryam Khanbaghi, Aleksandar Zečević
Electrical and Computer Engineering
Due to the aging power-grid infrastructure and increased usage of renewable energies, microgrids (μGrids) have emerged as a promising paradigm. It is reasonable to expect that they will become one of the fundamental building blocks of a smart grid, since effective energy transfer and coordination of μGrids could help maintain the stability and reliability of the regional large-scale power-grid. From the control perspective, one of the key objectives of μGrids is load management using local generation and storage for optimized performance. Accomplishing this task can be challenging, however, particularly in situations where local generation is unpredictable both in quality and …
Structures, Properties, And Applications Of Cnt-Graphene Heterostructures, Wei Du, Zubair Ahmed, Qi Wang, Cui Yu, Zhihong Feng, Guoyuan Li, Min Zhang, Changjian Zhou, Richard Senegor, Cary Y. Yang
Structures, Properties, And Applications Of Cnt-Graphene Heterostructures, Wei Du, Zubair Ahmed, Qi Wang, Cui Yu, Zhihong Feng, Guoyuan Li, Min Zhang, Changjian Zhou, Richard Senegor, Cary Y. Yang
Electrical and Computer Engineering
Both carbon nanotube (CNT) and graphene exhibit excellent properties and have many potential applications in integrated circuits, composite materials, thermal management, sensors, energy storage, and flexible electronics. However, their superior properties are confined to one or two dimensions, thus limiting their utility in interconnects or thermal interface materials that require a 3D structure for efficient electron and/or phonon transport. It is conceivable that a combined CNT-graphene structure would provide new opportunities for realizable applications in these and other fields. In recent years, numerous results on synthesis, structural analyses, theoretical modeling, and potential applications of various CNT-graphene heterostructures have been reported. …
Conductive Contact Area Estimation For Carbon Nanotube Via Interconnects Using Secondary-Electron Imaging, Yusuke Abe, Makoto Suzuki, Anshul Vyas, Cary Y. Yang
Conductive Contact Area Estimation For Carbon Nanotube Via Interconnects Using Secondary-Electron Imaging, Yusuke Abe, Makoto Suzuki, Anshul Vyas, Cary Y. Yang
Electrical and Computer Engineering
A major challenge for carbon nanotube (CNT) to become a viable replacement of copper and tungsten in the next-generation on-chip via interconnects is the high contact resistance between CNT and metal electrodes. A first step in meeting this challenge is an accurate characterization of via contact resistance. In this paper, the scanning electron microscope (SEM) image contrast at low landing energy is employed to estimate the conductive CNT area inside vias. The total conductive CNT area inside each via is deduced using SEM image with 0.1 keV landing energy and a specified threshold brightness, yielding via resistance versus CNT area …
Optimization Of Carbon Nanotube Ultracapacitor For Cell Design, Antonis Orphanou, Toshishige Yamada, Cary Y. Yang
Optimization Of Carbon Nanotube Ultracapacitor For Cell Design, Antonis Orphanou, Toshishige Yamada, Cary Y. Yang
Electrical and Computer Engineering
We report a methodology to optimize vertically grown carbon nanotube (CNT) ultracapacitor (CNU) geometrical features such as CNT length, electrode-to-electrode separation, and CNT packing density. The electric field and electrolyte ionic motion within the CNU are critical in determining the device performance. Using a particle-based model (PBM) based on the molecular dynamics techniques we developed and reported previously, we compute the electric field in the device, keep track of the electrolyte ionic motion in the device volume, and evaluate the CNU electrical performance as a function of the aforementioned geometrical features. We show that the PBM predicts an optimal CNT …
Electrical And Structural Analysis Of Cnt-Metal Contacts In Via Interconnects, Patrick Wilhite, Anshul A. Vyas, Jason Tan, Cary Y. Yang, Phillip Wang, Jeongwon Park, Hua Ai, Murali Narasimhan
Electrical And Structural Analysis Of Cnt-Metal Contacts In Via Interconnects, Patrick Wilhite, Anshul A. Vyas, Jason Tan, Cary Y. Yang, Phillip Wang, Jeongwon Park, Hua Ai, Murali Narasimhan
Electrical and Computer Engineering
Vertically aligned carbon nanotubes grown by plasmaenhanced chemical vapor deposition offer a potentially suitable material for via interconnects in next-generation integrated circuits. Key performance-limiting factors include high contact resistance and low carbon nanotube packing density, which fall short of meeting the requirements delineated in the ITRS roadmap for interconnects. For individual carbon nanotube s, contact resistance is a major performance hurdle since it is the dominant component of carbon nanotube interconnect resistance, even in the case of vertically aligned carbon nanotube arrays. In this study, we correlate the carbon nanotube-metal interface nanostructure to their electrical properties in order to elucidate …
Visible-Light Photoresponse Of Aln-Based Film Bulk Acoustic Wave Resonator, Changjian Zhou, Yi Yang, Y. Shu, Hualin Cai, Tian-Ling Ren, Mansun Chan, J. Zhou, Hao Jin, Shurong Dong, Cary Y. Yang
Visible-Light Photoresponse Of Aln-Based Film Bulk Acoustic Wave Resonator, Changjian Zhou, Yi Yang, Y. Shu, Hualin Cai, Tian-Ling Ren, Mansun Chan, J. Zhou, Hao Jin, Shurong Dong, Cary Y. Yang
Electrical and Computer Engineering
Visible-light photoresponse of an AlN-based film bulk acoustic wave resonator (FBAR) is demonstrated. It is found that the FBAR exhibits a resonant frequency downshift under purple light illumination and the magnitude of the frequency downshift increases as the power density increases within the range of 5–40 mW/cm2. A resonant frequency downshift of 1313 KHz is observed under 40 mW/cm2 illumination, corresponding to a minimum detection power of 6.09 nW. A sub-bandgap photoresponse of the AlN thin film is proposed to explain this phenomenon.
Breakdown Voltage Of Ultrathin Dielectric Film Subject To Electrostatic Discharge Stress, Hao Jin, Shurong Dong, Meng Miao, Juin Jei Liou, Cary Y. Yang
Breakdown Voltage Of Ultrathin Dielectric Film Subject To Electrostatic Discharge Stress, Hao Jin, Shurong Dong, Meng Miao, Juin Jei Liou, Cary Y. Yang
Electrical and Computer Engineering
Ultrathin silicon oxide film for nano-electromechanical system (NEMS) applications is investigated under electrostatic discharge (ESD) stress using a transmission line pulse (TLP) tester. The measured breakdown voltage and transient response are analyzed. The results show that the voltage stress time has a significant effect on the breakdown voltage. By shortening the stress time, the breakdown voltage increases by 2–3 times. With the area shrinking breakdown voltage increases, and there is a critical value, below which the breakdown voltage increases dramatically with decreasing area. It is possible to enhance the ESD robustness by using a multiple small-area dielectric layer structure. Shorten …
Change In Carbon Nanofiber Resistance From Ambient To Vacuum, Shusaku Maeda, Patrick Wilhite, Nobuhiko Kanzaki, Toshishige Yamada, Cary Y. Yang
Change In Carbon Nanofiber Resistance From Ambient To Vacuum, Shusaku Maeda, Patrick Wilhite, Nobuhiko Kanzaki, Toshishige Yamada, Cary Y. Yang
Electrical and Computer Engineering
The electrical properties of carbon nanofibers (CNFs) can be affected by adsorbed gas species. In this study, we compare the resistance values of CNF devices in a horizontal configuration in air and under vacuum. CNFs in air are observed to possess lower current capacities compared to those in vacuum. Further, Joule heating due to current stressing can result in desorption of gas molecules responsible for carrier trapping, leading to lower resistances and higher breakdown currents in vacuum, where most adsorbed gaseous species are evacuated before any significant re-adsorption can occur. A model is proposed to describe these observations, and is …
Extraction Of Contact Resistance In Carbon Nanofiber Via Interconnects With Varying Lengths, Ken Li, Patrick Wilhite, Vinit Khera, Shoba Krishnan, Xuhui Sun, Cary Y. Yang
Extraction Of Contact Resistance In Carbon Nanofiber Via Interconnects With Varying Lengths, Ken Li, Patrick Wilhite, Vinit Khera, Shoba Krishnan, Xuhui Sun, Cary Y. Yang
Electrical and Computer Engineering
A method to extract the contact resistance and bulk resistivity of vertically grown carbon nanofibers (CNFs) or similar one-dimensional nanostructures is described. Using a silicon-compatible process to fabricate a terrace test structure needed for the CNF length variation, the contact resistance is extracted by measuring in situ the resistances of individual CNFs with different lengths and within a small range of diameters using a nanoprober inside a scanning electron microscope. Accurate determination of contact resistances for various combinations of catalysts and underlayer metals can lead to eventual optimization of materials’ growth and device fabrication processes for CNF via interconnects.
Tunneling Between Carbon Nanofiber And Gold Electrodes, Toshishige Yamada, Tsutomu Saito, Makoto Suzuki, Patrick Wilhite, Xuhui Sun, Navid Akhavantafti, Drazen Fabris, Cary Y. Yang
Tunneling Between Carbon Nanofiber And Gold Electrodes, Toshishige Yamada, Tsutomu Saito, Makoto Suzuki, Patrick Wilhite, Xuhui Sun, Navid Akhavantafti, Drazen Fabris, Cary Y. Yang
Electrical and Computer Engineering
In a carbon nanofiber (CNF)-metal system such as a bridge between two gold electrodes, passing high current (current stressing) reduces the total resistance of the system (CNF resistance RCNF plus contact resistance Rc) by orders of magnitude. The role of current stressing is modeled as a reduction in the interfacial tunneling gap with transport characteristics attributed to tunneling between Au and CNF. The model predicts a reduction in Rc and gradual disappearance of the nonlinearity in the current-voltage (I-V) characteristics as Rc decreases. These results are consistent with measured I-V behavior.
High Efficient Electrical Stimulation Of Hippocampal Slices With Vertically Aligned Carbon Nanofiber Microbrush Array, Edward D. De Asis Jr., T. D. Barbara Nguyen-Vu, Prabhu U. Arumugam, Hua Chen, Alan M. Cassell, Russell J. Andrews, Cary Y. Yang, Jun Li
High Efficient Electrical Stimulation Of Hippocampal Slices With Vertically Aligned Carbon Nanofiber Microbrush Array, Edward D. De Asis Jr., T. D. Barbara Nguyen-Vu, Prabhu U. Arumugam, Hua Chen, Alan M. Cassell, Russell J. Andrews, Cary Y. Yang, Jun Li
Electrical and Computer Engineering
Long-term neuroprostheses for functional electrical stimulation must efficiently stimulate tissue without electrolyzing water and raising the extracellular pH to toxic levels. Comparison of the stimulation efficiency of tungsten wire electrodes (W wires), platinum microelectrode arrays (PtMEA), as-grown vertically aligned carbon nanofiber microbrush arrays (VACNF MBAs), and polypyrrole coated (PPy-coated) VACNF MBAs in eliciting field potentials in the hippocampus slice indicates that, at low stimulating voltages that preclude the electrolysis of water, only the PPy-coated VACNF MBA is able to stimulate the CA3 to CA1 pathway. Unlike the W wires, PtMEA, as-grown VACNF MBA, and the PPy-coated VACNF MBA …
Contact Resistance In Carbon Nanostructure Via Interconnects, Wen Wu, Shoba Krishnan, Toshishige Yamada, Xuhui Sun, Patrick Wilhite, Raymond Wu, Ke Li, Cary Y. Yang
Contact Resistance In Carbon Nanostructure Via Interconnects, Wen Wu, Shoba Krishnan, Toshishige Yamada, Xuhui Sun, Patrick Wilhite, Raymond Wu, Ke Li, Cary Y. Yang
Electrical and Computer Engineering
We present an in-depth electrical characterization of contact resistance in carbon nanostructure via interconnects. Test structures designed and fabricated for via applications contain vertically aligned arrays of carbon nanofibers (CNFs) grown on a thin titanium film on silicon substrate and embedded in silicon dioxide. Current-voltage measurements are performed on single CNFs using atomic force microscope current-sensing technique. By analyzing the dependence of measured resistance on CNF diameter, we extract the CNF resistivity and the metal-CNF contact resistance.
Secondary Electron Imaging Of Embedded Defects In Carbon Nanofiber Via Interconnects, Makoto Suzuki, Yusuke Ominami, Takashi Sekiguchi, Cary Y. Yang
Secondary Electron Imaging Of Embedded Defects In Carbon Nanofiber Via Interconnects, Makoto Suzuki, Yusuke Ominami, Takashi Sekiguchi, Cary Y. Yang
Electrical and Computer Engineering
Carbon nanofiber (CNF) via interconnect test structures are fabricated with the bottom-up process proposed by Li et al. [Appl. Phys. Lett. 82, 2491 (2003)] for next-generation integrated circuit technology. Critical defects in the interconnect structure are examined using scanning electron microscopy. It is shown that secondary electron signal with optimized incident beam energy is useful for detecting embedded defects, including unexposed CNF plugs and voids in the dielectric layer. The defect imaging mechanisms are elucidated based on beam-induced charging of the specimen surface.
Secondary Electron Emission From Freely Supported Nanowires, Makoto Suzuki, Kazuhiro Kumagai, Takashi Sekiguchi, Alan M. Cassell, Tsutomu Saito, Cary Y. Yang
Secondary Electron Emission From Freely Supported Nanowires, Makoto Suzuki, Kazuhiro Kumagai, Takashi Sekiguchi, Alan M. Cassell, Tsutomu Saito, Cary Y. Yang
Electrical and Computer Engineering
We present secondary electron (SE) emission results from freely supported carbon/silicon nitride (Si3N4) hybrid nanowires using scanning electron microscopy. We found that, contrary to bulk materials, the SE emission from insulating or electrically isolated metallic nanowires is strongly suppressed by the penetrating beam. A mechanism of the SE suppression by the positive specimen charging is proposed, which is based on a total emission yield calculation using the Monte Carlo technique. This finding provides an important basis for studying low-energy electron emission from nanostructures under a penetrating electron beam.
Improved Contact For Thermal And Electrical Transport In Carbon Nanofiber Interconnects, Tsutomu Saito, Toshishige Yamada, Drazen Fabris, Hirohiko Kitsuki, Patrick Wilhite, Makoto Suzuki, Cary Y. Yang
Improved Contact For Thermal And Electrical Transport In Carbon Nanofiber Interconnects, Tsutomu Saito, Toshishige Yamada, Drazen Fabris, Hirohiko Kitsuki, Patrick Wilhite, Makoto Suzuki, Cary Y. Yang
Electrical and Computer Engineering
We study the performance and reliability of carbon nanofiber (CNF) interconnects under high-current stress by examining CNF breakdown for four test configurations, suspended/supported with/without tungsten deposition. The use of W is to improve the CNF-electrode contact. The supported cases show a larger current density just before breakdown than the suspended ones, suggesting an effective heat dissipation to the substrate. The W-deposited contacts reduce the initial total resistance from megaohm range without W to kilo-ohms. High-current stress does not change the total resistance of the test structures with W unlike those without W deposition.
Length Dependence Of Current-Induced Breakdown In Carbon Nanofiber Interconnects, Hirohiko Kitsuki, Toshishige Yamada, Drazen Fabris, John R. Jameson, Patrick Wilhite, Makoto Suzuki, Cary Y. Yang
Length Dependence Of Current-Induced Breakdown In Carbon Nanofiber Interconnects, Hirohiko Kitsuki, Toshishige Yamada, Drazen Fabris, John R. Jameson, Patrick Wilhite, Makoto Suzuki, Cary Y. Yang
Electrical and Computer Engineering
Current-induced breakdown is investigated for carbon nanofibers (CNF) for potential interconnect applications. The measured maximum current density in the suspended CNF is inversely proportional to the nanofiber length and is independent of diameter. This relationship can be described with a heat transport model that takes into account Joule heating and heat diffusion along the CNF, assuming that breakdown occurs when and where the temperature reaches a threshold or critical value.
Bright-Field Transmission Imaging Of Carbon Nanofibers On Bulk Substrate Using Conventional Scanning Electron Microscopy, Makoto Suzuki, Quoc Ngo, Hirohiko Kitsuki, Kristofer Gleason, Yusuke Ominami, Cary Y. Yang
Bright-Field Transmission Imaging Of Carbon Nanofibers On Bulk Substrate Using Conventional Scanning Electron Microscopy, Makoto Suzuki, Quoc Ngo, Hirohiko Kitsuki, Kristofer Gleason, Yusuke Ominami, Cary Y. Yang
Electrical and Computer Engineering
The authors present scanning transmission electron microscopy (STEM) of carbon nanofibers (CNFs) on a bulk substrate using conventional scanning electron microscopy (SEM) without specimen thinning. By utilizing the electron beam tilted >85° from the substrate normal, bright-field STEM contrast is obtained for the CNFs on substrate with conventional SEM. Analysis of the observed contrast using Monte Carlo simulation shows that the weakly scattered electrons transmitted from the CNF are selectively enhanced by the largely tilted substrate and result in the observed STEM contrast. This mechanism provides a useful STEM imaging technique to investigate the internal structure of materials on bulk …
Current-Induced Breakdown Of Carbon Nanofibers, Makoto Suzuki, Yusuke Ominami, Quoc Ngo, Cary Y. Yang, Alan M. Cassell, Jun Li
Current-Induced Breakdown Of Carbon Nanofibers, Makoto Suzuki, Yusuke Ominami, Quoc Ngo, Cary Y. Yang, Alan M. Cassell, Jun Li
Electrical and Computer Engineering
We present a study of high-field transport in carbon nanofibers (CNFs) and breakdown phenomena due to current stress. In situ measurements with scanning transmission electron microscopy reveal that the failure mode of CNFs is strongly related to the morphology of graphite layers comprising CNFs. Comparison with carbon nanotube (CNT) breakdown is made, demonstrating that the current capacity of CNFs is described by a similar model as that of CNTs with a modification of the current capacity of each graphitic layer. The maximum current density is correlated with resistivity, leading to the conclusion that lower resistivity results in higher current capacity …
Monte Carlo Simulation Of Scanning Electron Microscopy Bright Contrast Images Of Suspended Carbon Nanofibers, Makoto Suzuki, Toshishige Yamada, Cary Y. Yang
Monte Carlo Simulation Of Scanning Electron Microscopy Bright Contrast Images Of Suspended Carbon Nanofibers, Makoto Suzuki, Toshishige Yamada, Cary Y. Yang
Electrical and Computer Engineering
The authors present a Monte Carlo study of previously observed bright contrast from carbon nanofibers suspended over the underlying substrate using scanning electron microscopy (SEM). The analysis shows that the origin of the bright contrast is mainly the increase in the secondary electron signal from the substrate when a gap between the nanofiber and substrate exists. The SEM signal dependence on the gap height is well reproduced by Monte Carlo simulation as well as a derived analytical expression. The bright contrast prevails when the SEM beam size is much smaller than the nanofiber diameter.
Interface Characteristics Of Vertically Aligned Carbon Nanofibers For Interconnect Applications, Yusuke Ominami, Quoc Ngo, Makoto Suzuki, Alexander J. Austin, Cary Y. Yang, Alan M. Cassell, Jun Li
Interface Characteristics Of Vertically Aligned Carbon Nanofibers For Interconnect Applications, Yusuke Ominami, Quoc Ngo, Makoto Suzuki, Alexander J. Austin, Cary Y. Yang, Alan M. Cassell, Jun Li
Electrical and Computer Engineering
The authors characterize the detailed interface structure of Ni-catalyzed vertically aligned carbon nanofibers (CNFs) prepared by plasma-enhanced chemical vapor deposition for interconnect applications. Stacked graphitic layers and cup-shape structures of CNFs around the interface region have been observed using high-resolution scanning transmission electron microscopy. The interaction between the Ni catalyst and Ti layer dramatically affects the CNF structure during initial growth. The effect of interface nanostructures on contact resistance is also discussed.
Bright Contrast Imaging Of Carbon Nanofiber-Substrate Interface, Makoto Suzuki, Hirohiko Kitsuki, Quoc Ngo, Cary Y. Yang
Bright Contrast Imaging Of Carbon Nanofiber-Substrate Interface, Makoto Suzuki, Hirohiko Kitsuki, Quoc Ngo, Cary Y. Yang
Electrical and Computer Engineering
We present the contrast mechanisms of scanning electron microscopy (SEM) for visualizing the interface between carbon nanofibers (CNFs) and the underlying substrate. SEM imaging with electron beam energies higher than a certain threshold provides different image contrasts depending on whether CNFs are in contact with the substrate or suspended above the substrate. CNFs with diameters ranging from 25to250nm are examined with various electron beam energies. It is found that the threshold energy corresponds to the energy required to penetrate the CNF and its dependence on CNF diameter can be understood using the theory of electron range. This knowledge will be …
Structural Characteristics Of Carbon Nanofibers For On-Chip Interconnect Applications, Yusuke Ominami, Quoc Ngo, Alexander J. Austin, Hans Yoong, Cary Y. Yang, Alan M. Cassell, Brett A. Cruden, Jun Li, M. Meyyappan
Structural Characteristics Of Carbon Nanofibers For On-Chip Interconnect Applications, Yusuke Ominami, Quoc Ngo, Alexander J. Austin, Hans Yoong, Cary Y. Yang, Alan M. Cassell, Brett A. Cruden, Jun Li, M. Meyyappan
Electrical and Computer Engineering
In this letter, we compare the structures of plasma-enhanced chemical vapor deposition of Ni-catalyzed and Pd-catalyzed carbon nanofibers (CNFs) synthesized for on-chip interconnect applications with scanning transmission electron microscopy (STEM). The Ni-catalyzed CNF has a conventional fiberlike structure and many graphitic layers that are almost parallel to the substrate at the CNF base. In contrast, the Pd-catalyzed CNF has a multiwall nanotubelike structure on the sidewall spanning the entire CNF. The microstructure observed in the Pd-catalyzed fibers at the CNF-metal interface has the potential to lower contact resistance significantly, as our electrical measurements using current-sensing atomic force microscopy indicate. A …
Spectroscopic Ellipsometry And Electrical Studies Of As-Grown And Rapid Thermal Oxidized Si1−X−YGeXCY Films, W. K. Choi, W. Feng, L. K. Bera, Cary Y. Yang, J. Mi
Spectroscopic Ellipsometry And Electrical Studies Of As-Grown And Rapid Thermal Oxidized Si1−X−YGeXCY Films, W. K. Choi, W. Feng, L. K. Bera, Cary Y. Yang, J. Mi
Electrical and Computer Engineering
Transmission electron microscopy results showed the formation of SiC precipitation in a rapid thermally oxidized (RTO) Si1−x−yGexCy sample with high-C content. The spectroscopic ellipsometry results showed that the E1 gap increased and E2 gap decreased as the C concentration increased. For the oxidized samples, the amplitude of the E2 transitions reduced rapidly and the E1 transition shifted to a lower energy. The reduction in the E2 transitions was due to the presence of the oxide layer. A high-Ge content layer and the low-C content in the RTO films accounted for …
Electrical Properties Of Rapid Thermal Oxides On Si1−X−YGeXCY Films, L. K. Bera, W. K. Choi, W. Feng, Cary Y. Yang, J. Mi
Electrical Properties Of Rapid Thermal Oxides On Si1−X−YGeXCY Films, L. K. Bera, W. K. Choi, W. Feng, Cary Y. Yang, J. Mi
Electrical and Computer Engineering
The electrical characteristics of rapid thermal oxides on Si1−x−yGexCy layers are reported. X-ray photoelectron spectroscopy results indicate segregation of Ge at the SiO2/Si1−x−yGexCy interface, a thin GeO2 layer at the oxide surface, and elemental Ge at the interface and in the oxide. The interface state density of the samples ranges from 3.0×1011 to 3.6×1012 eV−1 cm−2. All the samples show electron trapping behavior and the trap generation rate decreases with increasing C concentration. The charge-to-breakdown value and the oxide breakdown field are …
Structural Characterization Of Rapid Thermal Oxidized Si1−X−YGeXCY Alloy Films Grown By Rapid Thermal Chemical Vapor Deposition, W. K. Choi, J. H. Chen, L. K. Bera, W. Feng, K. L. Pey, J. Mi, Cary Y. Yang, A. Ramam, S. J. Chua, J. S. Pan, A. T.S. Wee, R Liu
Structural Characterization Of Rapid Thermal Oxidized Si1−X−YGeXCY Alloy Films Grown By Rapid Thermal Chemical Vapor Deposition, W. K. Choi, J. H. Chen, L. K. Bera, W. Feng, K. L. Pey, J. Mi, Cary Y. Yang, A. Ramam, S. J. Chua, J. S. Pan, A. T.S. Wee, R Liu
Electrical and Computer Engineering
The structural properties of as-grown and rapid thermal oxidized Si1−x−yGexCy epitaxial layers have been examined using a combination of infrared, x-ray photoelectron, x-ray diffraction, secondary ion mass spectroscopy, and Raman spectroscopy techniques. Carbon incorporation into the Si1−x−yGexCy system can lead to compressive or tensile strain in the film. The structural properties of the oxidized Si1−x−yGexCy film depend on the type of strain (i.e., carbon concentration) of the as-prepared film. For compressive or fully compensated films, the oxidation process drastically reduces the carbon content so that …
Properties Of Schottky Contacts Of Aluminum On Strained Si1-X-YGeXCY Layers, Jian Mi, Ashawant Gupta, Cary Y. Yang
Properties Of Schottky Contacts Of Aluminum On Strained Si1-X-YGeXCY Layers, Jian Mi, Ashawant Gupta, Cary Y. Yang
Electrical and Computer Engineering
Schottky contacts of Al/Si1-x-yGexCy were fabricated using conventional Si technology. Effects of thermal processing of the alloys on the electrical properties of the Al/Si1-x-yGexCy Schottky diodes were investigated. Current–voltage (I–V), capacitance–voltage (C–V), and x‐ray diffraction measurements were performed. These thick alloy films (100–150 nm) experienced strain relaxation upon annealing at 700 °C. Nearly ideal I–V and C–V behaviors were obtained for strain‐compensated samples. I–V and C–Vcharacteristics show evidence of dislocation‐related traps for strain‐relaxed samples. Carbon incorporation improves the I–V and C–V characteristics by lessening the extent of lattice relaxation due …