bluuebunny/crossref_metadata_2025_split huggingface dataset:
Degradation of the Acousto-Electric Current Saturation Behavior in C-Axis Fiber-Textured Polycrystalline Zinc Oxide Films
Authors: Pompe T. , Srikant V. , Clarke D. R. 
Published: April 2011

AbstractAcousto-electric current saturation has been observed in thin, polycrystalline Al-doped zinc oxide films grown on fused quartz. The films, grown by laser ablation, are c-axis textured with high angle grain boundaries between the grains. After annealing at 600°C in 0.1 mtorr oxygen, the films exhibit a current saturation at a current density of 2 105 A/cm2 and electric fields of 5 103 V/cm. However, under constant field the current density falls and the current saturation behavior is not maintained. Current saturation at the same current density can, however, be restored by increasing the electric field. Similarly, the appearance and disappearance of the current saturation behavior can be reversibly controlled by annealing in different oxygen partial pressures at 200°C. The degradation phenomena is attributed to the high acoustic flux enhancing the diffusion of oxygen along the grain boundaries where oxygen can alter the grain boundary potential barrier and hence the electric field in the grains.
Semiconductor Septum ELectrochemical Photovoltaic Cell
Authors: Tien H.Ti , Ren Pengcheng , Luo Wenxiu , Tan Zhongke , Ottova Angelica L. 
Published: April 2011

AbstractWe report the use of semiconductor septum electrochemical photovoltaic (SC-SEP) cell, modeled after green plant photosynthesis, in an application of solar energy conversion. A SC-SEP cell consists of a thin film of CdSe deposited on a metallic substrate (Ti, Ni, or stainless steel) as a bipolar septum electrode separating two aqueous solutions. It has been established that, upon irradiation of the septum electrode with visible light of the solar spectrum, photogenerated electron-hole pairs are separated under the influence of electric field. On the side of the septum electrode facing the light, the most powerful oxidant (holes) will oxidize species in the bathing solution, while the most powerful reducing agent (electrons) present on the dark side will carry out reduction of heavy metal ions or evolve hydrogen from aqueous solutions including seawater. Specifically, we report the use of photon energy generated electrons and ‘holes’ for the cleavage water to hydrogen and/or valuable chemicals in SC-SEP cells.
Correlation Between the Quantized Energies and the Photovoltaic Spectra for a GaAs/A1GaAs Quantum Well Structure
Authors: Russo O. L. , Rehn V. , Nee T. W. , Dumas K. A. 
Published: April 2011

AbstractWe have measured the photovoltaic spectra at 300K for a PIN GaAs/AlGaAs structure containing five coupled wells (50A/28A) grown by molecular beam epitaxy (MBE). The spectra were obtained in the energy range from 1.40 eV to 1.60 eV. This is the region in which optical transitions between the sub-band valence and conduction states are possible. Five direct optical transitions are allowed for this structure. These transitions are normally difficult to measure at room temperature because of broadening, nevertheless, some of the allowed transitions were observed from the photovoltaic spectra and agreed with calculations. We have previously shown that measurements made using electroreflectance (ER) agree with these results. However, with ER, three possible transitions were observed but only one with certainty, possibly because of interference caused by adjacent line spectra interaction. This interference appears to be less pronounced in the photovoltaic spectra, which aids in the identification of transitions.
Structure and Numerical Simulation of Field Effect Solar Cell
Authors: Koinuma H. , Fujioka H. , Hu C. , Koida T. , Kawasaki M. 
Published: April 2011

AbstractA p-i-n a-Si:H solar cell structure which can eliminate detrimental effect of TCO and a heavily doped window layer has been investigated in detail using a two-dimensional device simulator. The cell is designed to use an inversion layer induced by field effect instead of the heavily doped window layer while maintaining p-i-n junction locally to keep the built-in potential high and stable. Device simulation has revealed that the conversion efficiency of p-in a-Si:H solar cells can be improved by 30% with the use of this cell structure. This improvement is mainly due to the increase in the photo-currents, which can be explained by the increased quantum efficiency for light with short wavelength.
In Situ Observations of Pre-Patterned Void Interactions Under Electromigration-Induced Stress
Authors: Frankovic Richard , Bernstein Gary H. 
Published: April 2011

AbstractElectromigration (EM) void nucleation and growth is a failure mechanism of integrated circuit (IC) metallization. The time-to-failure of interconnect lines depends on the void nucleation time and the void growth time. The current understanding of the void growth stage is minimal, and characterization of the void growth stage is essential to further explain EM performance of IC metal interconnections. This work used high-resolution electron-beam lithography to define small dimension edge-voids into gold lines at various separation distances from each other, on the same side or opposite sides of the lines. The EM-induced interaction behavior of pre-defined voids was measured in a FESEM in-situ. Results showed that for small separation distances, void-void interaction enabled shape changes in the pre-patterned voids. For larger separation distance, void-void interactions could be characterized by secondary, induced void and hillock area measurements. As the separation distance increased, the void-void interaction diminished, and the voids acted independently of each other.
Experimental Measurements of Grain Boundary Rotation Toward Bamboo in Post-Pattern Annealing
Authors: Barr D. L. , Brown W. L. , Ohring M. 
Published: April 2011

AbstractThe microstructure of 0.8.µm, A1(0.5% Cu) lines has been measured both before and after post-pattern annealing in nitrogen at various times and temperatures. Grain boundary inclinations in single grain segments of lines were determined from Focused Ion Beam (FIB) images of two surfaces of the lines. The statistical distributions of inclination angles before and after annealing reveal the tendency for boundaries to rotate to reduce their area. In these experiments the rotation stagnates with the normals to the grain boundaries having a distribution of inclinations with a FWHM of about 33 degrees around the line direction.
Direct Correlation Between Grain Configuration and Electromigration Damage Development
Authors: Shih W. C. , Ghiti A. , Low K. S. , Greer A. L. , O'Neill A. G. , Walker J. F. 
Published: April 2011

AbstractThe development of electromigration-induced voids and hillocks in Al - 4 wt. % Cu interconnects is monitored by scanning electron microscopy during interrupted testing and is correlated directly with the actual grain configuration including precipitates. The short segments under study and their grain structures are defined and observed using focused ion beam microscopy. The Cu content in precipitate grains is swept away before electromigration damage, and at most such grains there is subsequent grain thinning. The observations are compared with the results from a computer simulation based on a finite-element calculation of self-consistent current density and temperature distributions. For the first time the simulation uses the actual grain configuration and incorporates Cu atom migration, and back-fluxes driven by stress and concentration gradients. In the simulation the grain-boundary diffusivity is taken to be independent of boundary misorientation or is varied according to randomly assigned orientations. The comparison of the voiding in these two simulated cases and the observations shows that some grain configurations are very susceptible to electromigration damage whatever the diffusivities. For most configurations, however, the misorientation dependence of grainboundary diffusivity is significant and must be included if simulations are to be realistic.
Effect of Growth Conditions on the Reliability of Ultrathin MOS Gate Oxides
Authors: Yang Tien-Chun , Saraswat Krishna C. 
Published: April 2011

AbstractIn this work we demonstrate that in MOS devices the reliability of ultrathin (< 100Å) gate oxide is a strong function of growth conditions, such as, temperature and the growth rate. In addition, for constant current gate injection the degradation of SiO2 is enhanced as the thickness is reduced. We attribute this to physical stress in SiO2 resulting from the growth process. The degradation is always more for those growth conditions which result in higher physical stress in SiO2. Higher temperatures and slower oxidation rates allow stress relaxation through viscous flow and hence result in SiO2 of better reliability. We also found that for constant current stressing, the interface damage is more at the collecting electrode than at the injecting electrode. ΔDit (stress induced interface state generation) can be reduced after a high temperature Ar post anneal after the gate oxide growth.
The Effect of the Passivation Material on the Stress and Stress Relaxation Behavior of Narrow Al-Si-Cu Lines
Authors: Witvrouw A. , Flinn P. , Maex K. 
Published: April 2011

Abstract800 nm thick and 1 jim wide Al-lwt.%Si-0.5wt.% Cu parallel lines with I μm spacing were passivated with PECVD oxide, oxynitride or nitride. Substrate curvature measurements as a function of temperature and XRD-measurements at room temperature were used to characterize macroscopic samples of these parallel Al-Si-Cu-lines. By using both techniques the average inplane stresses for the Al-Si-Cu lines as well as for the covering passivation material can be determined as a function of temperature. The highest and lowest stresses in the Al-Si-Cu are observed for lines with nitride and oxide passivations, respectively. Also the number of voids in the lines after a storage test at 250 °C is clearly highest for a nitride passivation and lowest for an oxide passivation.The stress in the passivation itself and its temperature dependence is found to be very different from the stress in a blanket passivation film.
Analysis Of Stresses And Strains In Passivated Metal Lines
Authors: Eppler I. , Schroeder H. , Burges U. , Schilling W. 
Published: April 2011

AbstractPassivated metal lines, commonly used in integrated circuits, show thermally induced stresses due to the difference of the thermal expansion coefficients of the lines and their surroundings. These stresses cause voidage and plastic flow of the lines. Aim of the analysis was to derive equations connecting experimentally measured strains or stresses by the X-ray diffraction and wafer curvature techniques with the magnitude of voidage and plastic shear deformation of the lines.Using the concepts of linear elasticity the volume averaged stresses of an array of parallel interconnects embedded in a passivation layer on a flat substrate are analysed. Equations are derived connecting the volume averaged stresses in the metal and in the passivation with the “eigen-strains” of the metal which characterize the true (stress free) thermal strains and plastic deformation strains of the metal. The coefficients entering these equations are determined from (elastic) finite element method (FEM) calculations performed for various geometries and aspect ratios of the metal lines. Choosing the proper values of the coefficients allows the eigen- strains to be determined from the experimental data.By comparison of the evaluated eigen-strains with the purely elastic eigen-strains ΔaΔT the extent of voidage and/or plastic shear deformation of passivated metal lines caused by thermally induced stresses can be determined model independently.
Local and Global Stress Distributions in BEOL Metallization
Authors: Noyan I. C. , Liniger E. G. , Hu C-K. , Wang P-C. , Cargill G. S. 
Published: April 2011

AbstractDesign of reliable thin film metallization is a complex problem that requires information about local parameters such as composition, microstructure, residual and loading stresses, etc. On the other hand, such information has been traditionally obtained using techniques that have sampling volumes that are appreciably larger than the BEOL dimensions currently in use. In this article, the x-ray residual stress analysis technique and its extensions to micro-domain measurements are reviewed. These concepts are then applied to strain data from in-situ x-ray measurements, obtained in real-time from Al metallization lines subjected to thermal stressing and electromigration.
Self-Interstitial Supersaturation During Ostwald Ripening of End-of-Range Defects in Ion-Implanted Silicon
Authors: Seibt M. 
Published: April 2011

AbstractModified Ostwald ripening theory is used to calculate the time evolution of the size distribution function of extended end-of-range defects in ion implanted silicon. This allows to compare the time dependent self-interstitial supersaturation during postimplantation annealing in the presence of Frank-type stacking faults with that in the presence of {311} - defects. It is shown that the latter affect self-interstitial concentrations up to the point where they dissolve whereas the former are irrelevant from the point of view of transient enhanced diffusion.
Measurement of Lateral Dopant Diffusion in Rapid Thermal Annealed W-Polycide Gate Structures
Authors: Schiml T. , Bevk J. , Furtsch M. , Georgiou G. E. , Cirelli R. , Mansfield W. M. , Silverman P. J. , Lufrman H. S. 
Published: April 2011

AbstractLateral dopant diffusion is a well known problem in dual-gate W-polycide CMOS devices. We have recently demonstrated that RTA processing helps to alleviate this problem and at the same time ensures sufficient dopant activation. However, due to the complex micro-structural changes in both poly-Si and WSix (x˜2.5) layers during the RTA process, the time dependence of the diffusion processes and dopant distribution are difficult to predict. Consequently, the process optimization and device simulations are rather unreliable. We describe a new experimental technique to measure lateral dopant diffusion and 2-dimensional dopant distribution in RTA processed W-polycide structures using conventional SIMS analysis of lithographically defined test structures. Our experiments show that the technique is capable of measuring lateral dopant diffusion over distances between one and tens of microns without losing the vertical resolution of conventional SIMS profiling. The technique can be used to study diffusion processes in a variety of materials and multi-layer structures.
Rapid Thermal Dopants Diffusion and Surface Passivation for Silicon Solar Cells Applications
Authors: Slaoui Abdelilah , Lachiq Aziz , Ventura Laurent , Muller Jean Claude 
Published: April 2011

AbstractLimiting thermal exposure time using Rapid Thermal Processing (RTP) is now emerging as a promising simplified process for manufacturing of terrestrial solar cells in a continuous way. In this work, we present results on simultaneous formation of emitter, back-surface field and surface passivation in a single rapid thermal cycle. Spin-on dopants (SOD) solutions are used as dopant sources. Optimal emitter profiles, low sheet resistances and high gettering effect are reached. The residual SOD film is used as a surface passivation layer. Solar cells with efficiencies in the range 10 – 14 % are obtained depending on temperature and time processing.
Bonded-H in Gate Dielectrics Deposited by Plasma Assisted Chemical Vapor Deposition and Subjected to Rapid Thermal Annealing
Authors: Lucovsky G. , Niimi H. , Koh K. 
Published: April 2011

AbstractThe incorporation of bonded nitrogen into ultra thin SiO2 gate dielectrics has become an important technology issue. Nitrogen atoms bonded in the immediate vicinity of the Si-SiO2 interface improve device reliability in n-channel field effect transistors. N- atom incorporation at the monolayer concentration range has been achieved by remote plasma assisted oxidation in N2O at 300°C. The incorporation mechanism and the stability of bonded-N are discussed.
Temperature Measurement at RTP Facilities-An Overview
Authors: Wagner J. , Boebel F. G. 
Published: April 2011

AbstractTemperature is one of the most important quantities in semiconductor manufacturing. It plays a fundamental role in many standard production techniques and especially at RTP facilities. We will give an overview on standard temperature measurement techniques associated with RTP. Their basic principles, advantages and disadvantages will be discussed with respect to explicit applications.The potential physical and technical possibilities of optical temperature measurement are outlined as well as the problems like scattering, emissivity change and irradiation by halogen lamps. An overview on practical solutions of these problems is given together with explicit examples for applications including costs and benefits of their application.
Pattern Related Non-Uniformities During Rapid Thermal Processing
Authors: Bremensdorfer R. , Marcus S. , Nenyei Z. 
Published: April 2011

AbstractState of the art rapid thermal processing is able to produce a lateral thermal homogeneity which is within the inherent resolution limits of current meterology. For the most commonly used direct or indirect control methods such as multiple thermocouple measurements, rapid thermal oxidation (RTO), or rapid thermal annealing (RTA) of plain semiconductor wafers this limit is ± 2°C. As homogeneity requirements approach those limits, pattern induced non-uniformities are getting more important.In order to achieve rapid heating and high substrate temperatures in RTP, heater and substrate are not in equilibrium and their emission spectra differ considerably. Under such circumstances laterally varying optical characteristics on the substrate itself imply thermal non-uniformities. The influence of patterns on a silicon wafer surface on the temperature uniformity is studied. Passive patterns showing interference effects were formed out of thermal oxide and Si3N4. RTO and RTA, as well as embedded thermocouples were used for temperature measurement. The data presented show that major non-uniformities due to interference effects can be reduced by restricting the energy transfer through the patterned side of the wafer. It is shown that independent top and bottom heater bank control and controlled thermal kinetics are suitable methods to reduce the pattern related process non-uniformities.
Low Temperature Selective Si Epitaxy Using Si2H6 and Cl2: Investigations into Selectivity Robustness and Epitaxial Film Quality
Authors: O'Neil Patricia A. , Violette Katherine E. , Öztürk Mehmet C. , Batchelor Dale , Maher Dennis M. 
Published: April 2011

AbstractIn this paper, we explore selective Si epitaxy by UltraHigh Vacuum Rapid Thermal Chemical Vapor Deposition (UHV-RTCVD) using Si2H6, H2, and C12 with particular emphasis on selectivity robustness. Two key parameters considered in this study were partial pressures of Si2H6 and H2. It was found that excessive increases in either partial pressure could lead to selectivity degradation. The two mechanisms by which the observed selectivity degradation can be explained are as follows: A higher Si2H6 partial pressure provides a larger flux of Si atoms which directly influences the probability of reaching the critical nuclei size for stable nuclei formation while an increase in H2 partial pressure reduces the desorption rate of Si adatoms from the insulator surface by reducing the available Cl in the gas phase for SiC12 formation. The impact of process parameters on epitaxial defect density was also evaluated using darkfield imaging. The results clearly indicate increasing defect density upon increases in both the chlorine flow rate and the level of contamination introduced through the silicon source gas.
Strategies for the Reduction of Pattern Effects
Authors: Kerscih A. , Schafbauer T. , Deutschmann L. 
Published: April 2011

AbstractThe pattern effects in hot processes arise from a spatial variation of the radiative heat flux imbalance between emission and absorption. There are two scenarios to reduce the pattern effect: a very reflective chamber facing the patterned side with an illumination from the backside or a controlled double sided illumination on the other hand. The paper demonstrates the mechanism of both scenarios with a simple mathematical model and discusses the limitations of the approaches. The results will be exemplified with the help of reactor scale simulations involving a detailed Monte Carlo radiation model featuring continuous spectral dependence.
How Rapid Isothermal Processing Can be a Dominant Semiconductor Processing Technology in the 21st Century
Authors: Singh R. , Sharangpani R. , Cherukuri K. C. , Chen Y. , Dawson D. M. , Poole K. F. , Rohatgi A. , Narayanan S. , Thakur R. P. S. 
Published: April 2011

AbstractThe growth and advancement of the electronic and photonic industry in the 21 st century hinges on revolutionary new processing techniques that will overcome some of the most fundamental limitations of conventional methods. Rapid isothermal processing (RIP) based on incoherent radiation as the source of optical and thermal energy can play a major role in designing processing systems that offer the tight process control, low thermal budgets, low microscopic defects, high throughput and high yields required for almost every semiconductor device. Conventional RIP can be further optimized by fully exploiting the contribution of quantum photoeffects. The improved performance and reliability offered by RIP will make it the mainstream technology for the green manufacture of microelectronics, optoelectronics, solar cells, flat panel displays and microelectromechanical systems. Key issues related to the cost of ownership, design of RIP system based on the full utilization of photo–thermal effects and model based control systems are described. New experimental results for a number of processing steps are provided. These results demonstrate the importance of advanced RIP systems in providing better performance and lower defects for future devices.
Microwave processing CaO-Al203-SiO2 Glass Using Sol-Gel Technique
Authors: Zhou Y. , Biest O. Van der , Groffils C. , Luypaert P. J. 
Published: April 2011

AbstractGels in the CaO-A12O3-SiO2 (CAS) system were successfully converted into glass in a single mode, tuneable, cylindrical microwave applicator, operating at 2.45 GHz in the TM012 mode. Transparent glasses were formed as a result of the direct microwave heating of homogeneous CAS gels to well above their melting temperature (1170°C). The effect of processing parameters, such as incident power level, sample mass and location, and thermal insulation has been investigated. The excellent coupling of the CAS gel with microwave can be understood from the structural evolution during sol-gel processing.
Microwave Sintering of Pure and Doped Nanocrystalline Alumina Compacts
Authors: Bruce R. W. , Fliflet A. W. , Kurihara L. K. , Chow G.-M. , Schoen P. E. 
Published: April 2011

AbstractA single-mode cavity microwave furnace, operating in the TE103 mode at 2.45 GHz is being used to investigate sintering of pure and doped nanocrystalline alumina. The purpose of these experiments is to determine the effect of additives on the sintering process in the nanocrystalline regime. Using the sol-gel method, high purity Al2O3 nanocrystalline powders were synthesized. These powders were calcined at 700°C and then CIP'ed to 414 MPa, producing 0.4 in. diameter, 0.25 in. high cylindrical compacts. The compacts were heated in the microwave furnace to temperatures between 1100°C to approximately 1800°C and were then brought back to room temperature using a triangular heating profile of about 30 minutes duration. A two-color IR pyrometer was used to monitor the surface temperature of the workpiece. The additives tested in this work lowered the temperature needed for densification but this effect was offset by increased grain growth. Initial grain growth from < 5 nm to ∼ 50 nm was closely correlated with the γ to α-alumina phase transition.