bluuebunny/crossref_metadata_2025_split huggingface dataset:
Preparation and Properties of ferroelectric Bi2SrTa2O9 thin films for FeRAM using Flash-MOCVD
Authors: Ami T. , Hironaka K. , Isobel C. , Nagel N. , Sugiyama M. , Ikeda Y. , Watanabe K. , Machida A. , Miura K. , Tanaka M. 
Published: April 2011

ABSTRACTFerroelectric Bi2 SrTa2 O9 thin films were successfully prepared by liquid delivery MOCVD, and structural and electrical properties were investigated. As-deposited films showed sharp distinct peaks, which were indexed assuming a fluorite-type structure. These precursors were transformed to bismuth-layered structures by annealing at 800 °C in flowing oxygen. Reasonable ferroelectric properties were observed in a film with 170 nm-thickness. Remanent polarization and coercive field were estimated to be 5.2 μC/cm2 and 52 kV/cm, respectively, at 5V.
The Microstructure of SrBi2Ta2O9 Films
Authors: Gutleben C.D. , Ikeda Y. , Isobe C. , Machida A. , Ami T. , Hironaka K. , Morita E. 
Published: April 2011

ABSTRACTWe present the results of an investigation of the microstructural properties of layered-structure perovskite SrBi2Ta2O9 films grown by Flash-MOCVD, conventional CVD, and MOD. The films grown by Flash-MOCVD on Pt electrode layers, were polycrystalline and showed acceptable ferroelectric properties and low leakage. TEM showed that the individual crystallites were of high quality and, on average about 300nm in diameter. TEM also gave some indications of a disordered phase interspersed amongst the crystallites.A complete, high-resolution set of XPS spectra gathered from these films confirmed that the basic perovskite structures were predominately single phased but that they were, in all cases, accompanied by a significant amount of mobil clusters of Bi metal. We speculate that this Bi metal corresponds to the disordered phase seen by TEM and show that appropriate ozone annealing is able to remove all evidence of it.
High Temperature X-Ray Diffraction Study of PbTio3 Thin Films Grown on Mgo(001) by MOCVD
Authors: Batzer R.S. , Yen Biming , Liu Donhang , Kubo H. , Bai G.R. , Chen Haydn 
Published: April 2011

ABSTRACTLead titanate (PT) is ferroelectric in its tetragonal phase (c/a=1.06). The domain formation is coupled to the relaxation of internal stress generated by a combination of lattice mismatch, transformation strain and differential thermal stress. The mechanism of domain formation in an epitaxially grown PT film is related to the substrate type and the growth temperature. In this study, PT films have been deposited on MgO(001) in a coldwall, horizontal metal organic chemical vapor deposition (MOCVD) system. The structure of domains and their evolution have been measured as a function of temperature by the x-ray diffraction method using a hot stage. Domain structure changes were observed by θ−2θ scans, ω scans, as well as in-plane φ scans. Effect of film stress on the ferroelectric transition temperature is discussed. Reproducibility of domain formation as a result of temperature cycling both below and above Tc is assessed.
Chemical Vapor Deposition of Oxides From Alkoxides
Authors: Xu R. 
Published: April 2011

ABSTRACTMOCVD of oxides can be achieved through deposition reaction schemes such as oxidation, thermal pyrolysis, plasma assisted pyrolysis, radiation-assisted pyrolysis or any combinations of these free-radical processes. Chemically mild and clean reaction schemes such as the hydrolysis-polycondensation and the hydrolysis-assisted pyrolysis reactions are found favorable for stoichiometric depositions using alkoxide complex precursors. We review the various reaction schemes and try to point out comparatively the advantages and disadvantages of each. Experiments in the deposition of lithium tantalate from alkoxide complex precursors are presented. Low deposition temperature, high deposition rate and autostoichiometry capabilities are demonstrated in the experiments.
The Properties of GaInAsSb/GaSb Heterostructure Grown by Mocvd and P-GaInAsSb/N-GaSb Photodiodes
Authors: Zhang Baolin , Jin Yixin , Zhou Tianming , Jiang Hong , Ning Yongqiang , Li Shuwei 
Published: April 2011

ABSTRACTGaInAsSb/GaSb heterostructures have been grown by metalorganic chemical vapor deposition (MOCVD). The optical properties were characterized using low temperature(71K) photoluminescence(PL) and infrared transmission spectroscopy. The FWHM of the typical PL spectrum peaked at 2.3μm is 30meV. Hall measurement results for undoped GaInAsSb layers are presented showing a p-type background and low hole concentration of 6.5 × 1015cm−3. The room temperature performances of the p-GaInAsSb/n-GaSb photodiodes are reported. Its responsivity spectrum is peaked at 2.2 5μm and cuts off at 1.7μm in the short wavelength and at 2.4μm in the long wavelength, respectively. The room temperature detectivity D* is of 1 × 109cm.Hz1/2.W−2
Improvement Of Pecvd-SiNx For Tft Gate Insulator By Controlling Ion Bomberdment Energy
Authors: Kasama Yasuhiko , Ohmi Tadahiro , Fukuda Koich , Fukui Hirobumi , Iwasaki Chisato , Ono Shoich 
Published: April 2011

ABSTRACTIt has been revealed that ion energy and ion flux density play an essentially critical role in SiNx deposition process of PECVD in TFT-LCD production. Ion energy and ion flux density bombarding onto substrate surface are known to be extracted from waveform of RF applied to an electrode. Using this method, authors investigated film quality of SiNx formed in the conventional parallel plate PECVD equipment. When N2+H2 or N2+Ar is employed as a carrier gas in source gas(SiH4+NH3), authors have defined normalized ion flux density as ion flux density divided by deposited SiNx molecule which must be increased to obtain high quality SiNx film while ion energy is suppressed at low level as not giving damages on the film surface. This technique has made it possible to securely form SiNx film (2500 Å) featuring dielectric breakdown field intensity of 8.5MV/cm at 250°C on a glass substrate with Cr gate interconnects of 1000 Å having vertical step structure. One of the important factors to improve film quality of SiNx deposited in PECVD is to increase ion flux density while keeping ion energy low enough to protect growing surface against any damages. Using this technique inverse-staggered TFT-array featuring field effect mobility of 0.96 •/V·s has been demonstrated which gate insulator SiNx, non-doped a-Si:H and a- Si:H(n+) were formed continuously at the same substrate temperature of 2500°C.
Group 13-16 Precursors: What Controls Their Volatility?
Authors: Gillan Edward G. , Bott Simon G. , Barron Andrew R. 
Published: April 2011

ABSTRACTThe volatility of a series of group 13–16 cubane compounds, [(R)ME]4 (M = Al, Ga; E = S, Se, Te) has been investigated by thermogravimetric analysis. The effects of the M4E4 core, the ligand (R), and molecular packing on the relative sublimation temperature and the activation energy of sublimation are discussed. For any given ligand type (e.g., [(tBu)ME] 4) volatility is dependent on the compound's molecular mass. The volatility of a homologous series (e.g., [(R)GaS] 4) is proposed to be dependent on the interlocking of the ligands in the solid state. In contrast, the energy of activation for sublimation (Ea) may be related to the molecular packing of the cubane cores in the solid state.
Kinetics And Morphology Of Homoepitaxial Cvd Growth On Diamond (100) And (111)
Authors: Rawles R. E. , Morris W. G. , D’Evelyn M. P. 
Published: April 2011

ABSTRACTGrowth rates for homoepitaxy of diamond (100) and (111) by hot-filament chemical vapor deposition were measured via in situ Fizeau interferometry and the surface morphologies were subsequently characterized by atomic force microscopy (AFM). (100)-oriented growth from 0.5% CH4 in H2 exhibited pure Arrhenius behavior, with an activation energy of 17±1 kcal/mol, up to a substrate temperature of 1100°C. Addition of oxygen to the feed gas resulted in an increased growth rate below 900°C, a maximum growth rate between 900 and 1000°C, and etching (of diamond) above 1050 - 1100°C. However, the presence of oxygen apparently had less effect on the surface morphology than did the (100)-to-(111) growth rate parameter α, determined directly from the relative growth rates of (100) and (111) substrates mounted side by side. During homoepitaxial growth from 0.5% CH4 in H2 at 875°C of ca. 1-micron-thick films,α = was 2.2 without oxygen and 1.3 for growth with 0.14% O2. The (100) film grown with α = 2.2 was quite smooth, while that with α = 1.3 was covered by numerous hillocks and penetration twins. AFM analysis revealed surprisingly little difference between the (111) films despite the considerable difference in α. Implications of these results for the growth mechanism are discussed.
Nanoscale Modification Of Amorphous Diamond-Like Carbon Film Surfaces
Authors: Mercer T. W. , Dinardo N. J. , Sullivan J. P. , Friedmann T. A. , Siegal M. P. , Martinez-Miranda L. J. 
Published: April 2011

ABSTRACTScanning Tunneling and Atomic Force Microscopy (STM, AFM) of amorphous tetrahedral carbon films (a-tC) film surfaces grown by pulsed laser deposition indicate extreme flatness and uniform electronic properties.1 This is consistent with the observed predominance of sp3 (diamond-like) bonding in these materials.2 Potential applications of a-tC films may be enhanced with the ability to modify their surfaces on the nanoscale. Exploiting the metastable nature of the sp3 hybridized state of carbon, the high flux electron beam from an STM tip was used to modify ˜100 nm regions; processing in air or in vacuum produces similar results. STM and AFM maps of the modified regions indicate stable morphologic and electronic structures consistent with a local transformation to sp2 (graphitic) hybridization. Surface potentiometric mapping of these regions indicates a correlation between electron dose and a lowering of the surface potential. In addition, spatially-resolved electron energy loss spectroscopy of the modified areas performed with a Scanning Auger Microscope shows plasmon energy shifts that confirm an elevated sp2 content in the modified regions.3
Growth Of Diamond Films From C-h-o MixturesM
Authors: Ford I. J. 
Published: April 2011

ABSTRACTA simple model of the competition between the growth of diamond and amorphous, graphitic carbon has been extended to include oxygen within the mixture of gases in a chemical vapour deposition (CVD) process. The model is based on linear rate equations which describe the growth and removal of layers of carbonaceous material on the surface of a substrate placed within the CVD reactor. The main effect of oxygen is to tie up a proportion of the available gas-phase carbon in the form of CO, which reduces the flux of reactive carbonaceous material onto the surface. Hydrogen atoms can remove carbonaceous material from the surface, and in addition can perform the key task of cementing such groups into place on the surface to make diamond. Starting with these simple assumptions, it is possible to account for the shape of the diamond domain in the C-H-O phase diagram, namely the boundaries with the domains of graphitic growth and no-growth.
Raman and FTIR Study of Neutron Irradiated CVD Diamond
Authors: Khasawinah S. , Popovici G. , Prelas M. A. , Mccormick M. , Loyalka S. K. , Manning G. , Farmer J. , White H. W. , Pour F. Shahedi 
Published: April 2011

ABSTRACTUndoped and 10B doped diamond films were neutron irradiated at a moderately high fluence level (thermal neutron fluence of 1.3 × 1020 n/cm2 and a fast neutron (E> 0.1 MeV) fluence of 1.6 × 1020 n/cm2). The unirradiated, irradiated, irradiated and annealed samples were studied using Fourier Transform Infrared (FTIR) and Raman spectroscopies. A dependence of radiation induced stress on the initial boron concentration was observed. The radiation induced stress was lower for the undoped samples. Correlations between FTIR and Raman data were found. The radiation damage was removed after annealing, as measured by Raman and FTIR spectroscopy.
Preparation of Diamond-Like Carbon by Pulsed Laser Deposition
Authors: Matsui T. , Yudasaka M. , Imai K. , Ohki Y. , Yoshimura S. 
Published: April 2011

ABSTRACTDiamond-like carbon (DLC) films have been prepared by pulsed laser deposition using graphite and cured phenol resin as targets. By comparison with previous reports, it is found that the lower power density (fluence) of irradiated pulsed laser can form DLC. In case of cured phenol resin used as a target, DLC was formed at almost the same wavelength and fluence region as that with graphite.
Diamond Growth Chemistry During Atmospheric-Pressure Plasma Cvd
Authors: Girshick S. L. , Lindsay J. W. 
Published: April 2011

ABSTRACTDiamond films were deposited by chemical vapor deposition using a radio- frequency induction plasma operating at 130 torr. Linear growth rates of polycrystalline diamond films ranged from 18 to 37 μm h-1. For a fixed substrate temperature of 1000°C the input methane-hydrogen ratio was varied from 2% to 10%. Over this range the resulting film morpologies changed from faceted ball-like structures to well-faceted diamond, then to non-faceted balls, and for the well- faceted films increases in methane-hydrogen ratio caused the film texture to shift toward the <100> direction. During these experiments gas sampled through an orifice in the center of the substrate was delivered to a gas chromatograph for measurement of stable hydrocarbon species. As the input methane-hydrogen ratio was increased the measured methane-acetylene ratio decreased. The gas chromatograph measurements showed marked differences from measurements made for an RF reactor with somewhat different flow geometry operating at atmospheric pressure.
Nickel catalyzed reconstruction of a diamond (110) surface
Authors: Smith C. , Chu C. J. , Margrave J. L. , Hauge R. H. 
Published: April 2011

ABSTRACTA polished diamond (110) surface was observed to undergo surface rearrangement above ˜700 °C to a micro faceted diamond surface when in contact with a nickel film and in the presence of hydrogen. Formation of a graphitic layer at the diamond-nickel interface above 700 °C was observed in the absence of hydrogen. The presence of 0.1 Torr of hydrogen was shown to be sufficient to prevent graphite formation at the nickel-diamond interface.
Surface damage effects on secondary electron emission From the negative electron affinity diamond surface
Authors: Malta D. P. , Posthill J. B. , Humphreys T. P. , Mantini M. J. , Markunas R. J. 
Published: April 2011

ABSTRACTThe effects of surface damage on the secondary electron emission characteristics of a natural diamond (100) surface have been investigated using ultraviolet photoelectron spectroscopy and scanning electron microscopy. Surface damage was intentionally induced by abrading the (100) diamond face with diamond paste. Removal of the damage was achieved by a sequence of ion implantation, graphitization, electrochemical etching and oxygen/argon plasma etching. Prior to characterization performed between steps in the sequence, the surface was hydrogenated by exposure to a hydrogen plasma in attempts to create a negative electron affinity surface condition. Upon removal of the surface damage, the secondary electron yield from the negative electron affinity surface was enhanced by a factor of ˜20 over that from the damaged negative electron affinity surface.
A Study of Dopants in Diamond Using Electron Paramagnetic Resonance Spectroscopy
Authors: Zvanut M. E. , Zhang Shigang , Carlos W. E. 
Published: April 2011

ABSTRACTChemical incorporation of impurities into diamond films is important for both electronic and optoelectronic applications. The study reveals the effect of incorporated dopants in diamond films using electron paramagnetic resonance (EPR), a non-destructive highly sensitive spectroscopy. Both the stress and damage associated with dopants is assessed using the center line of the EPR spectra. The films studied were grown by chemical vapordeposition and doped with phosphorus by two different methods, fast ion doping and chemical incorporation. The results suggest that damage increases with increased dopant density and saturates with dopant densities about l×1020 cm-3. Although electrical measurements did not reveal n-type conductivity, at low fluences the films grown using fast ion doping exhibited a density of 1017 cm-3 shallow substitutional phosphorus sites. Comparison of different dopants in the films doped by chemical incorporation show that phosphorus produces ten times greater damage than boron. Overall, the study illustrates that EPR may be used as a quick nondestructive characterization tool for diamond films.
The Current And Future Status Of Diamond in Electronics
Authors: Chalker Paul R. , M. Ian , Golder Buckley 
Published: April 2011

ABSTRACTBoth passive and active electronic applications of CVD diamond have been proposed since the earliest stages of its development, largely based on an extrapolation of the superlative properties of single crystal diamond. Consequently, CVD diamond research has striven hard to match up to this expectation and significant advances have been made.CVD diamond compares favourably with natural or high pressure synthetic single crystal material for passive electronic applications. The development of CVD diamond deposition technology for thermal management has led producers to address issues such as production cost, yield and quality. CVD polycrystalline diamond is becoming a commodity material and commercial applications in thermal management are emerging. Many of these developments are expected to feed into active electronic applications and will act as a springboard for diamond into commercial technology.The active electronic applications for diamond are more demanding in terms of materials and process technologies. For example, doping, structure delineation and contact schemes have been widely demonstrated and prototype devices are showing potential benefits in sensors, detectors, photonics and cold cathodes. The current and future status of diamond electronics is reviewed.
Homoepitaxial growth of CVD diamond: effect of nitrogen contaminations on growth rates
Authors: Wild C. , Locher R. , Koidl P. 
Published: April 2011

ABSTRACTHomoepitaxial diamond films were deposited on {100} and {111} oriented substrates using microwave plasma assisted CVD. The growth rate was measured in situ using laser interferometry. Various amounts of 15N2 were admixed to the process gas (0-50 ppm). The growth rate on {100} faces was found to increase significantly (by a factor 1.8) with increasing 15N2 content. In contrast, on { 111 } faces only a minor increase of the growth rate upon nitrogen admixture was observed. These findings are in perfect agreement with the observed influence of nitrogen contaminations on the α-parameter, as derived by the X-ray texture analysis of polycrystalline diamond films [1]
Thermal Decomposition of HMX: Low Temperature Reaction Kinetics and their Use for Assessing Response in Abnormal Thermal Environments and Implications for Long-Term Aging
Authors: Behrens Richard , Bulusu Suryanarayana 
Published: April 2011

AbstractThe thermal decomposition of HMX between 175°C and 200°C has been studied using the simultaneous thermogravimetric modulated beam mass spectrometer (STMBMS) apparatus with a focus on the initial stages of the decomposition. The identity of thermal decomposition products is the same as that measured in previous higher temperature experiments. The initial stages of the decomposition are characterized by an induction period followed by two acceleratory periods. The Arrhenius parameters for the induction and two acceleratory periods are (Log(A)= 18.2 ± 0.8, Ea = 48.2 ± 1.8 kcal/mole), (Log (A) = 17.15 ± 1.5 and Ea = 48.9 ± 3.2 kcal/mole), (Log (A) = 19.1 ± 3.0 and Ea = 52.1 ± 6.3 kcal/mole), respectively. The data can be used to calculate the time and temperature required to decompose a desired fraction of a test sample that is being prepared to test the effect of thermal degradation on its sensitivity or burn rates. It can also be used to estimate the extent of decomposition that may be expected under normal storage conditions for munitions containing HMX. The data, along with previous mechanistic studies conducted at higher temperatures, suggest that the process that controls the early stages of decomposition of HMX in the solid phase is scission of the N-NO2 bond, reaction of the NO2 within a “lattice cage” to form the mononitroso analogue of HMX and decomposition of the mononitroso HMX within the HMX lattice to form gaseous products that are retained in bubbles or diffuse into the surrounding lattice.
NTO Decomposition Studies
Authors: Oxley J. C. , Smith J. L. , Yeager K. E. , Rogers E. , Dong X. X. 
Published: April 2011

AbstractTo examine the thermal decomposition of 5-nitro-2,4-dihydro-3H-1,2,4-triazol-3-one (NTO) in detail, isotopic labeling studies were undertaken. NTO samples labeled with 15N in three different locations [ N(l) and N(2), N(4), and N (6)] were prepared.1 Upon thermolysis, the majority of the NTO condensed-phase product was a brown, insoluble residue, but small quantities of 2,4,-dihydro-3H- 1,2,4-triazol-3-one (TO) and triazole were detected.2 Gases comprised the remainder of the NTO decomposition products. The analysis of these gases is reported herein along with mechanistic implications of these observations.
AnAb Initio Investigation of Crystalline PETN
Authors: Kunz A. Barry 
Published: April 2011

AbstractSolid energetic substances have long played an important technological role as explosives and also as fuels. Much of the research on the solid phases has been concentrated on ground state properties, and also on the chemistry of the molecules comprising the solid. In addition, significant understanding of the detonation properties has been obtained by semi-empirical continuum mechanical modeling. Traditional solid state studies of this important class of materials have mostly been ignored. This may be due to the apparent success of the semi-empirical models in describing the detonation properties, as well as the practical difficulties in performing band theoretical studies. Recent interest in more fundamental questions relating to the basic properties of these systems as materials, coupled with a desire to probe fundamental questions relating to the initiation and sustaining of the chemical reactions leading to combustion/detonation is generating significant interest in the basic solid state properties of such energetic systems. In particular, recent analysis of detonation by J. J. Gilman emphasizes the need to include excitation of the electronic system in obtaining an understanding. In this manuscript, the basic solid state properties of PETN are considered.
Initiation of Crystalline Explosives by Shock or Impact
Authors: Coffey C. S. 
Published: April 2011

AbstractThe central issue determining initiation response of explosive crystals to shock or impact is the generation of the energy necessary to cause molecular dissociation. This controls the initial rate of release of chemical energy. Here, the energy dissipated in the crystals as they undergo plastic deformation due to shock or impact is taken to be the source of the energy required to achieve initiation. This determines initiation sensitivity to shock or impact. Several problems are discussed including initiation of detonation and the von Neumann pressure spike structure of a detonation wave.