bluuebunny/crossref_metadata_2025_split huggingface dataset:
Surface Morphology of Ingap in the Ai-Free Pump Ld
Authors: Choo Ahn Goo , Kim Seong Heon , Kim Nam Heon , Laboutine Oleg , Yu Joon Sang , Kim Tae Il 
Published: April 2011

AbstractWe have studied the effects of growth parameters and substrate orientations on InGaP quality using Normarski microscopy, photoluminescence (PL) spectrum and atomic force microscopy (AFM). The full width at half maximum (FWHNM) and peak position of PL spectrum were closely related with the surface morphology. The InGaP layers of narrower FWHM and shorter peak wavelength had smoother surface morphology. The InGaP layers grown on (100) substrates at the moderately low reactor pressure showed rougher surface than those on the tilted substrates. But the surface morphology was noticeably improved to be mirror-like at the lower reactor pressure. The surface morphology was inverted between the exact and tilted substrates in this reactor pressure. Furthermore, the samples grown on the tilted substrate exhibited rougher surface than the samples grown on the exact substrate. (111)B-misoriented growth surfaces had smoother than (111)A-misoriented surfaces.
Structural and Electrical Properties of Ni/Co Superlattices Using Pb as a Surfactant
Authors: Iwanami M. , Furukawa R. , Matsumoto T. , Kamiko M. , Yamamoto R. 
Published: April 2011

AbstractTo obtain informations about the correlation between structure and electrical property in metallic multilayers, we have fabricated Ni/Co superlattices with and without Pb as a surfactant by molecular beam epitaxy. From the observations of RHEED and x-ray diffraction patterns, we confirmed that the surfaces of Ni/Co superlattices with Pb are flatter and the interfaces are sharper than one without Pb, which means that Pb operates as an effective surfactant.We have investigated the electrical properties of superlattices by measuring magnetoresistance. The initial change of resistance with magnetic field from 0 to 1 kOe was larger for the superlattices with a surfactant, while once magnetic field was applied, the effect of a surfactant to resistivity change was not observed. This suggests that Pb also changes the initial magenetic domain structure and the magnetotransport property of Ni/Co superlattice is not sensitive to interface structure.
Skewed Height Distributions of Kinetically Roughened Films
Authors: Kleban P. , Krim J. , Ruffing C. 
Published: April 2011

AbstractWe examine height distribution functions (height histograms) of kinetically roughened metal films, making use of STM data for vapor-deposited Ag on quartz. The height distribution of the raw data is Gaussian to quite high accuracy. However, if one averages each height over a region of length scale L, the resulting distributions deviate increasingly from Gaussian behavior, becoming skewed as L increases. We quantified this behavior by means of moments of the distribution; with increasing L a non-negligible third moment appears. The responsible morphology is minima that tend to form steep valleys or deep pits while the corresponding (at the same height above the average) maxima tend to form rounded hilltops. Skewed height distributions have been predicted on the basis of model calculations, but not previously observed to our knowledge.
Evolution of Interfacial Roughness Correlations of Fe Au Films Grown on Mgo(001) Substrates
Authors: Chow P. C. , Paniago R. , Forrest R. , Moss S. C. , Parkin S. S. P. , Cookson D. 
Published: April 2011

AbstractThe growth by sputtering of a series of thin films of Fe/Au on MgO(001) substrates was analyzed using Bragg and diffuse X-ray scattering. The Fe (bcc) layer grows rotated by 45° with respect to the MgO – Au(fcc) (001) epitaxial orientation, resulting in an almost perfect match between the two metallic structures. By collecting the X-ray diffuse scattering under grazing incidence using a 2-dimensional image plate detector, we mapped the reciprocal space of these films. We characterized the correlated interface roughness starting with a buffer of Fe in which only three interfaces are present. The propagation of the roughness was subsequently characterized for Fe/Au multilayers with 40 and 100 bilayers. We observe an enlargement of the surface features as a function of time, evidenced by the longer lateral cutoff length measured for thicker films.
Autocorrelation Function and Roughness Spectrum of a Growing Film Surface
Authors: Trofimov V. I. 
Published: April 2011

AbstractRecently we developed a method that allows to derive a height-height autocorrelation function (ACF) for a randomly rough surface of a thin – film growing by the 3D island mechanism. In this paper, the ACF and roughness spectrum for several versions of the island growth model deduced by this method are presented and discussed. In the model dimension d=1+1 the ACFs are deduced in exact analytical form, and for d=2+1 the ACF' s are calculated numerically. In both model dimensions for the rms roughness the universal analytical expression connecting its with physical deposition parameters is derived. The impact of the growth hillock shape and the hillock space distribution are studied. It is shown that the ACF form is determined by the hillock space distribution and in the cases of an ideally random Poisson distribution and slightly ordered distribution the ACF is nearly gaussian although the surface profile height distribution is non-gaussian. The rms roughness is strongly dependent on the hillock shape while the autocorrelation length is determined by the hillock number density. The theoretical predictions are compared with published TEM and STM-data and the scaling behaviour of the rms roughness is analysed.
Surface Structure and Morphology of SrBi2Ta2O9 (SBT) Thin Films
Authors: Li Tingkai , Zawadzki Pete , Stall Richard A. , Peng Chien-Hsiung , Zhu Yongfei , Desu Seshu B. 
Published: April 2011

AbstractSrBi2Ta2O9 (SBT) films have been prepared by MOCVD processes. The phase formation, surface structure, morphology and surface roughness of SBT films on Pt/Ti/SiO2/Si wafers were measured by XRD, SEM, AFM and ellipsometry. It was found that amorphous SBT formed below 500°C, amorphous and polycrystalline growth occurred successively between 500°C and 650°C. The surface roughness of the SBT thin films also increased with increasing deposition temperature. The AFM results showed the nucleation of SBT started by island formation, then continued across the surface of substrates at lower deposition temperatures. When the SBT film was deposited at higher temperatures, the nucleation and grain growth occurred at the same time, resulting in an inhomogencous structure and much higher surface roughness. Therefore, a two step process is used to improve surface roughness and interface mismatch between film and substrate. In addition, the relationships between surface structure, morphology and the electric properties of SBT thin films were also investigated.
AFM Methodology for the Measurement of Silicon Wafer Microroughness
Authors: Gilicinski A.G. , Beck S.E. , Rynders R.M. , Moniot D.A. 
Published: April 2011

AbstractDespite the growing use of atomic force microscopy (AFM) for the measurement of silicon wafer microroughness, no generally accepted method has been developed to deal with issues around accuracy and reproducibility. We review problems that affect these AFM studies and demonstrate the effect of probe tip size on AFM microroughness data. Without knowledge of AFM probe tip geometry, it is impossible to quantitatively compare Ra or RMS microroughness data between different measurements. An experimental solution is to characterize tip sizes during imaging and compare data taken with similar size tips. While this will significantly improve quantitation, it is restrictive in that data taken with different size tips cannot be easily compared. We propose a solution to this problem in the use of power spectral density (PSD) to evaluate microroughness with a “cutoff frequency” at the lateral wavelength where tip effects begin to affect the accuracy of the microroughness measurement. An example of this approach is described
Structure Of The Defects Responsible For B-Mode Breakdown Of Gate Oxide Grown On The Surface Of Silicon Wafers
Authors: Mera T. , Jablonski J. , Danbata M. , Nagai K. , Watanabe M. 
Published: April 2011

AbstractCrystal-originated pits are known as the defects responsible for B-mode Time Zero Dielectric Break-down (TZDB) of the gate oxide grown on the surface of Si wafers. In order to clarify the breakdown mechanism, we have analyzed the structure of those defects formed at the surface of bare and oxidized wafers. In the latter case the analysis has been done both before and after gate oxide breakdown. Electric breakdown has been accomplished by Cu decoration method, recognized as an effective tool for unambiguous detection and positioning of the defects causing B-mode TZDB. As revealed by cross-sectional transmission electron microscopy (XTEM), crystal-originated pits at the bare wafer surface are polyhedral pits having about 5-nm-thick oxide layer on the inner walls. During gate oxidation the thermal oxide is growing faster on the pit walls than on the wafer surface, except for the pit comers where the oxide thinning has been observed. Resulting concave comers of the oxidized pits are suggested to be the weak spots where B-mode TZDB occurs.
Behavior Of Point Defects In CZ Silicon Crystal Growth-Formation Of Polyhedral Cavities And Oxidation-Induced Stacking Fault Nuclei
Authors: Tanahashi K , Inoue N. , Mizokawa Y. 
Published: April 2011

AbstractThe origin of oxidation–induced stacking faults (OSF) and polyhedral cavities in as–grown Czochralski silicon (CZ–Si) crystals is discussed with comparison to the behavior of previously investigated grown–in oxide precipitates. The incorporation, diffusion and reaction in the vacancy, self–interstitial and oxygen ternary system are considered to discuss the origin of grown–in defects.
Positron Beam Technique For The Study Of Defects At The Si/SiO2 Interface Of A Polysilicon Gated MOS System
Authors: Clement M. , Nijs J. M. M. De , Schut H. , Veen A. Van , Mallee R. , Balk P. 
Published: April 2011

AbstractThis work demonstrates that positrons implanted into a 60 nm n-type polysilicon layer with large grains, can be pushed out of this layer by an externally induced electric field. In the case of a metal-oxide-silicon (MOS) system with a such a polysilicon gate, polysilicon-implanted positrons can be efficiently transported towards the SiO2/Si interface where they all are collected. This technique offers new and interesting possibilities to study defects at the SiO2/Si interface of technologically important MOS systems.
True Atomic Resolution Imaging on Semiconductor Surfaces with Noncontact Atomic Force Microscopy
Authors: Sugawara Y. , Ueyama H. , Uchihashi T. , Ohta M. , Yanase Y. , Shigematsu T. , Suzuki M. , Morita S. 
Published: April 2011

AbstractThe constant vibration mode and the constant excitation mode in noncontact atomic force microscopy were compared to investigate the force interaction between tip and surface. As a result, we found that the constant excitation mode is much more gentle than the constant vibration mode. We also succeeded in atomic resolution imaging on InP(110) surface not only in the noncontact region but in the contact region for the first time. Furthermore, we found the discontinuity of the force gradient curve on reactive Si(111)7×7 reconstructed surface. We proposed a model to explain the discontinuity with the crossover between the physical and chemical bonding interaction.
Formation Of Er-Related Donor Centers During Postimplantation Annealing Of Si:Er
Authors: Sobolev N.A. , Aleksandrov O.V. , Shek E.I. 
Published: April 2011

AbstractDependence of the donor center concentration, the Er activation coefficient and the nlayer thickness on the implantation and subsequent annealing conditions was studied. A model of formation of donor centers has been developed. The model is based on the interaction of Er atoms with self-interstitials. It describes the dependence of electrical parameters of Er-doped layers on temperature and time of postimplantation annealing.
Cubo-Octahedral B12 Clusters In Silicon Crystal
Authors: Okamoto M. , Hashimoto K. , Takayanagi K. 
Published: April 2011

AbstractA new stable structure and the electronic structure of boron clusters in silicon crystal have been calculated using the first-principles local density functional approach for Si54B12H60 clusters. According to our calculation, the cubo-octahedral B12 cluster was found to be more stable than the icosahedral one proposed previously. The total energy difference was about 4.6 eV. The analysis of the partial density of states showed that the cubo-octahedral B12 cluster should act as a double acceptor.
Interactions Of Structural Defects With Metallic Impurities In Multicrystalline Silicon
Authors: McHugo S. A. , Hieslmair H. , Weber E. R. , Rosenblum M. D. , Kalejs J. P. 
Published: April 2011

AbstractInteractions between structural defects and metallic impurities were studied in multicrystalline silicon for solar cell applications. The objective was to gain insight into the relationship between solar cell processing, metallic impurity behavior and the resultant effect on material/device performance. With an intense synchrotron x-ray source, high sensitivity x-ray fluorescence measurements were utilized to determine impurity distributions with a spatial resolution of ≈ lμm. Diffusion length mapping and final solar cell characteristics gauged material/device performance. The materials were tested in both the as-grown state and after full solar cell processing. Iron and nickel metal impurities were located at structural defects in asgrown material, while after solar cell processing, both impurities were still observed in low performance regions. These results indicate that multicrystalline silicon solar cell performance is directly related to metal impurities which are not completely removed during typical processing treatments. A discussion of possible mechanisms for this incomplete removal is presented.
EPR Study Of Defect Formation In H Implanted And Annealed CZ Si
Authors: Pivac B. , Rakvin B. , Corni F. , Tonini R. , Ottaviani G. 
Published: April 2011

AbstractStructural defects produced in single crystal silicon after hydrogen ion implantation were studied by electron paramagnetic resonance spectroscopy. Samples implanted at 77K show the presence of vacancy clusters that serve as precursors for nanoblister formation upon subsequent thermal treatment. Evolution of vacancy clusters at various stages of thermal annealing show the influence of implanted hydrogen redistribution that passivates the paramagnetic activity in the intermediate temparature range. At still higher temperatures hydrogen outdifluses from the bulk activating remaining structural defects. At these temperatures, formed vacancy clusters gettered oxygen present in the bulk forming, therefore, VxOy complexes. Finally, at temperatures above 700°C vacancy clusters disintegrate completely.
Hrtem Study Of Dislocations In Gesi/Si Heterostructures Grown By VPE
Authors: Liang Jijnwu , Wan Xueyuan 
Published: April 2011

AbstractGeSi/Si heterostructures grown by atmospheric chemical vapor epitaxy have been studied by cross sectional high resolution transmission electron microscopy (HRTEM). For the first time we have observed an interstitial-type dislocation loop which is located near to a 60° misfit dislocation in the initially prepared GeSi/Si sample. After 30 minutes observation, the interstitial-type dislocation loop disappeared and the 60° dislocation climbed. Moreover, we have observed dissociated 60° dislocations with about 9 nm width of stacking fault existing in silicon substrate.
A New Measurement Method Of Micro Defects Near The Surface Of Si Wafers; Optical Shallow Defect Analyzer (Osda)
Authors: Takeda Kazuo , lshida Hidetsugu , Hiraiwa Atsushi 
Published: April 2011

AbstractTo inspect quality of the surface region (the depth < 0.5μm) of Si wafer, where devices are to be fabricated, a new measurement method named Optical Shallow Defect Analyzer (OSDA) is developed. This method is based on light scattering at two wavelengths having different penetration depths in silicon. The system measures the depth distribution and the size distribution of defects near the surface by comparing intensities of the two scattered lights. The depth resolution of 0.1 μm, the high measuring throughput (total 6“Φ surface area/1hr) and the minimum detectable defect size of 20 nm are achieved. The OSDA is a powerful measurement system for nondestructive quality check of silicon wafers. We first present the data of epitaxial grown-in defects in μm order thickness epitaxial layers about the defect densities, the size distribution and the depth distribution.
Nonradiative Investigation Of Hole Photoionization Spectrum Of EL2 In Semi-Insulating GaAs
Authors: Ikari T. , Fukuyama A. , Morooka Y. , Yoshino K. , Maeda K. , Akashi Y. 
Published: April 2011

AbstractThe piezoelectric photoacoustic (PPA) measurements before and after the secondary light illumination for 3 minutes were carried out at 85 K to investigate the electron and hole photoionization processes of EL2 in carbon concentration controlled semi-insulating (SI) GaAs. The result showed a broad peak around 1.0 eV and a hump up to the band gap energy. These were due to hole and electron photoionization processes of EL2, respectively, and these processes were clearly observed from a nonradiative recombination point of view for the first time. In addition, we found that the hole photoionization process of EL2 is not influenced by the secondary light illumination at low temperature. Although the electron photoionization underwent photoquenching effect upon an illumination of 1.12 eV, the hole photoionization process did not change even after a long period of illumination. The positively charged EL2 donor state may not transform to the metastable state.
Evidence For Non-Correlation Between The 0.15 eV And 0.44 eV Cu-Related Acceptor Levels In GaAs
Authors: Leosson K. , Gislason H. P. 
Published: April 2011

AbstractWe present investigations on the two dominating acceptor levels observed in Cu-diffused GaAs which have frequently been attributed to the two ionization levels of a double CuGa acceptor. We employed plasma hydrogenation and lithium diffusion followed by reverse-bias and zero-bias annealing to passivate and subsequently reactivate the Cu-related acceptor levels. Deep-level current-transient spectroscopy measurements reveal that the two levels are independently reactivated, strongly indicating that they arise from different defects.
Defect Characterization Of InAs Wafers Using Positron Lifetime Spectroscopy
Authors: Mahony J. , Mascher P. 
Published: April 2011

AbstractPositron lifetime measurements on InAs wafers have shown that the positron bulk lifetime in InAs is 246±2 ps. Most samples exhibit a defect lifetime of 287±6 ps, which is attributable to monovacancy-impurity complexes with a concentration of 7±2×10 16 cm-3. Very heavily doped n-type samples exhibit a defect lifetime of 332–340 ps, characteristic of divacancies. The concentration of these defects is also close to 1017 cm−3. Both types of defects are stable for rapid thermal annealing up to 850 °C, and both defects are neutral. The formation of the divacancytype defects may be correlated with a discrepancy between the carrier concentration and the total
Theory Of 3d Transition Metal Defects In 3C SiC
Authors: Overhof Harald 
Published: April 2011

AbstractThe electronic properties of 3d transition metal (TM) defects located on one of the four different tetrahedral positions in 3C SiC are shown to be quite site-dependent. We explain the differences for the 3d TMs on the two substitutional sites within the vacancy model: the difference of the electronic structure between the carbon vacancy VC and the silicon vacancy VSi is responsible for the differences of the 3d TMs. The electronic properties of 3d TMs on the two tetrahedral interstitial sites differ even more: the TMs surrounded tetrahedrally by four Si atoms experience a large crystal field splitting while the tetrahedral C environment does not give rise to a significant crystal field splitting at all. It is only in the latter case that high-spin configurations are predicted.
Donor Reactivation In Plasma-Irradiated GaAs Under Laser Illumination
Authors: Wada K. , Nakanishi H. 
Published: April 2011

AbstractReactivation of Si donors in Ar plasma-irradiated GaAs under reverse bias annealing (RBA) is substantially enhanced by Ar laser illumination. Reactivation occurs only in the surface layer and charge density overshoots its original donor density. These are identical to those observed by high temperature RBA without laser illumination. The activation energy of the reactivation rates is about 0.1 eV, whereas it is about 0.7 eV without laser illumination. The energy reduction is explained by charge state change of deactivators in terms of two hole capturing under minority carrier injection. These findings suggest that deep levels induced by complexes of Si donors with point defects should be present above midgap. The deep penetration mechanism of plasma-induced point defects is discussed, based on the present findings.
Octahedral Void Defects Causing Gate-Oxide Defects In Moslsis
Authors: Itsumi Manabu 
Published: April 2011

AbstractWe found oxide defects originating in standard Czochralski silicon and proposed the sacrificial oxidation method to eliminate these defects in about 1979. Later, N2 annealing and H2 annealing methods were proposed successively, and these three elimination methods have been successfully introduced into actual fabrication lines for highly reliable integrated circuits. However, the origin of the defect was not clarified until recently. We combined copper decoration and TEM in order to observe the origin of the oxide defects and for the first time, observed octahedral void defects systematically at the oxide defects with standard Czochralski silicon. The sizes of the defects are typically 0.1–0.2 microns. These Si-crystalline defects are the origin of oxide defects and, at the same time, may be the origin of crystal originated particles. Recently, we have observed octahedral void defects in the bulk of the standard Czochralski silicon too. Some experimental findings suggest that some impurities on the side wall of the octahedral void defect induce dielectric breakdown of the gate-oxides.
Effect of Fluorine Addition to Plasma-Enhanced Chemical Vapor Deposition Silicon Oxide Film
Authors: Lim S. W. , Miyata M. , Naito T. , Shimogaki Y. , Nakano Y. , Tada K. , Komiyama H. 
Published: April 2011

AbstractOne solution to reduce the time constant of ultra large scale integrated circuit (ULSI) is the use of a low dielectric constant intermetal film like fluorinated silicon oxide (SiOF). We could obtain SiOF films with low dielectric constant as low as 2.6 and good step coverage by adding CF4 to SiH4 and N2O in plasma-enhanced chemical vapor deposition (PECVD) process. To investigate the dielectric constants due to each polarization and the reason for the decrease in the dielectric constant, we used capacitance-voltage (C-V) and ellipsometry measurements, and Kramers-Kronig transformation. The decrease in dielectric constant could not be completely explained by the reduction in ionic and electronic polarization. We could detect silanol groups, Si-OH in the films and their decrease with increasing CF4 flow rate. It is suggested that the main polarization component to decrease dielectric constant is such as orientational polarization. The step coverage of film was improved by adding CF4. It is suggested that the reduction in the sticking probability of films forming species due to the change in surface state improved the step coverage.