bluuebunny/crossref_metadata_2025 huggingface dataset:
Selective Deposition of ZnS Thin Films by KrF Excimer Laser on Patterned Zn Seeds
Authors: Yamane K. , Murahara M.
Published: March 2011

The patterned Zn nucleation and the ZnS growth onto the Zn seeds on a thermal oxidized silicon substrate was demonstrated at room temperature with the excimer laser chemical vapor deposition method.

The formation of ZnS films was realized by the method based on the two—step process consisting of the nucleation and the subsequent ZnS growth. In the nucleation, a gaseous dimethylzinc was sealed in a reaction chamber and was then evacuated immediately. Then, the substrate surface which was uniformly adsorbed by dimethylzinc molecules was exposed with a single shot irradiation of a patterned KrF laser; Zn seeds were created only on the irradiated parts by a photodecomposition. And the subsequent growth of ZnS was performed by the parallel or perpendicular irradiation methods. As a result, in the perpendicular irradiation method, the high selectivity and crystallinity of the film were performed by irradiating the whole substrate surface with very low fluence of the KrF laser such as 3 mJ/cm2.
Vapor Deposited Ag2S Films as High Resolution Photoregistering Materials in The Infrared Region
Authors: Eneva J. , Kitova S. , Panov A , Haefke H.
Published: March 2011

Ag2S as a narrow band gap semiconductor is appropriate for photoimaging in the infrared (IR) region. Co-evaporation of Ag and S from two separate sources was used for preparing of thin Ag2S films with different Ag/S ratio. Gelatine subbed glass plates were used as substrates. The structure of the films obtained was examined by transmission electron microscopy and electron diffraction. The effects of chemical composition, film thickness and processing conditions on the photographic parameters were studied.

It is shown that after appropriate processing thin Ag2S films with stoichiometric composition can. be successfully used as high resolution (1600 lines/mm) photographic materials in the IR region.
First Principles Study of Aluminum Deposition on Hydrogenterminated Si(100) Surface
Authors: Sosa Carlos
Published: March 2011

The deposition of Aluminum on Si(100) surface has been investigated using density functional methods. This has been accomplished by adoption of a Si9H16 cluster to model the H terminated Si(100) 1XI surface and Si9H15 cluster to model the surface with an unpaired electron. The predicted NLSD dissociation energy for the Si9H16 → Si9H15 + H is 86.3 ± 2.0 Kcal/Mol. This is in agreement with previous theoretical calculations on similar systems.
Gasdynamics and Chemistry in The Pulsed Laser Deposition of Oxide Dielectric Thin Films
Authors: Hastie John W. , Bonnell David W. , Paul Albert J. , Schenck Peter K.
Published: March 2011

In the context of “chemistry and its effects on film quality,” we and a number of other research groups have developed spectroscopic and modeling approaches to better define the pulsed laser deposition process. An overview of these approaches is given here, using the results of recent work performed in our laboratory on the oxide dielectric systems of BaTiO3 and PbZr0.53Ti0.47O3(PZT).
Vaporization Chemistry of Organoaluminum Precursors to Ain
Authors: Crocco Paul D. , Hudson John B. , Wang Yi , Interrante Leonard V.
Published: March 2011

We have used the technique of molecular beam mass spectrometry, with time of flight measurement, to study the vaporization of two organoaluminum precursors to AIN. The compounds studied were the isomers (CH3)3Al·NH3 (I) and (CH3)3N·AIH3 (II). Compound I was synthesized in house by reaction of (CH3)3Al with NH3. Compound II was obtained commercially. Mass spectrometric measurements of Compound I indicated a room temperature vapor pressure below 1 Torr, and slow decomposition at room temperature to yield CH4 and a solid product, identified as the trimer, [(CH3)2AlNH2]3, as well as possible concentrations of the corresponding monomer and dimer. Similar measurements on Compound II indicated partial decomposition to metallic aluminum and gaseous trimethylamine and hydrogen.
Excimer Laser Interactions with Ptfe Relevant to thin Film Growth
Authors: Dickinson J.T. , Norton M.G. , Shin J.-J. , Jiang W. , Langford S.C.
Published: March 2011

Recently, thin films of polytetrafluroethylene (PTFE) have been grown using pulsed laser ablation of TeflonTM at 266 nm.1,2 To provide further insight into the growth mechanisms we have examined the neutral and charged particle emissions generated in vacuum by 0 - 3 J/cm2 pulses of 248 nm radiation incident on solid PTFE. Measurements include quadrupole and time-of-flight mass spectroscopy. We find in addition to the neutral monomer (C2F4), copious emissions of highly reactive neutral and charged radicals, e.g., CF2, CF3, CF, F, and Cx. A careful analysis of the fluence dependence of these products provides definitive evidence that their precursors are generated by a thermally driven unzipping reaction. Models for the production of the radical species with the observed energies (several eV) involving gas phase processes are presented. Implications for improving PTFE thin film growth will be discussed.
Diethyldiethoxysilane as a New Precursor for SiO2 Growth on Silicon
Authors: Wise Michael L. , Sneh Ofer , Okada Lynne A. , Dillon Anne C. , George Steven M.
Published: March 2011

Diethyldiethoxysilane (DEDEOS) is a potential single molecular precursor for SiO2 growth. Additionally, DEDEOS may be applicable in a deposition scheme that will allow precise atomic layer control of SiO2 film thicknesses. Deposition of SiO2 on silicon using DEDEOS was studied in three regimes. In the first regime, the adsorption and decomposition of DEDEOS were studied using temperature-programmed desorption (TPD) and Fourier-transform infrared spectroscopy (FTIR) under UHV conditions. TPD and FTIR results indicated that DEDEOS deposits ethyl and ethoxy species on the surface which decompose by a β-hydride elimination mechanism. In the second regime, step-wise SiO2 growth using DEDEOS was studied by laser-induced thermal desorption (LITD) and TPD as a function of repetitive growth cycles composed of DEDEOS deposition at 300 K followed by thermal annealing to 820 K. The amount of SiO2 growth per cycle initially decreased as a function of cycle until reaching a constant value after approximately 10 cycles. Finally, DEDEOS deposition of SiO2 was studied in a high pressure chamber at surface temperatures between 873 K and 1003 K and at a pressure of 0.5 Torr. The deposition of SiO2 as a function of exposure was found to display a fast initial growth step followed by a slower step which continued indefinitely. The activation energy for SiO2 growth by DEDEOS in the slower growth step was found to be 49 ± 6 kcal/mol. This activation energy is very similar to the activation energy of 45 kcal/mol observed for SiO2 growth by tetraethoxysilane (TEOS).
Kinetics of Reactive Ion Etching of Polymers in an Oxygen Plasma: The Importance of Direct Reactive Ion Etching
Authors: Graham Sandra W. , SteinbrüChel Christoph
Published: March 2011

The etching of polymer films in oxygen-based plasmas has been studied between 5 and 100 mTorr in a reactive ion etch reactor using Langmuir probe and optical actinometry measurements. Results for the etch yield (the number of carbon atoms removed per incident ion) are analyzed in terms of a surface-chemical model for ion-enhanced etching proposed by Joubert et al. (J. Appl. Phys. 65, 5096 (1989)). A proper description of the results requires that this model be modified by including a term due to direct reactive ion etching and physical sputtering. The contribution by direct reactive ion etching to the overall etching turns out to be significant under all conditions and even dominant at the lowest pressures. The modified model should be applicable to the etching of polymers in other types of reactors, especially highplasma- density reactors. The relationship between these results and the anisotropic patterning of polymer films is also discussed.
Decomposition Study of Teos in Thermal Cvd
Authors: Takeuchi Hideki , Izumi Hirohiko , Kawasaki Atsushi
Published: March 2011

Thermal decomposition of tetraethoxysilane(TEOS) has been investigated in a vertical type LP-CVD reactor. The mass spectrum of reacting gas was found to have a feature corresponding to hexaethoxysiloxane ((H5C2O)3SiOSi(OC2H5)3). Trapped byproducts were found to include ethanol and ethoxy-based silica. Kinetic analysis of deposition rate profile indicated the existence of two intermediates. Feed gas residence time, as well as substrate temperature. directly affected the film quality.

A vapor phase reaction model was proposed to explain these results. According to this model. TEOS decomposes into ethylene and triethoxysilanol. The latter reacts with TEOS to form hexaethoxysiloxane as observed by mass spectrometry. The triethoxysilanol, hexaethoxysiloxane and TEOS should be actual deposition precursors. Similar reaction continues to form ethoxybased siloxane polymers which are trapped from the exhaust gas.
The Role of Barium In the Heteroepitaxial Growth of Insulator and Semiconductors On Silicon
Authors: Chu T. K. , Santiago F. , Stumborg M. , Huber C. A.
Published: March 2011

The epitaxial growth of an insulator, BaF2, and semiconductors of the II-VI and the IV-VI families on Si substrates were carried out. In-situ XPS analyses during the growth of the first monolayers were used to study the surface chemical reactions involved. The results point to a common ingredient in these growths: that the Ba atoms are involved in forming interfacial compounds that would facilitate the heteroepitaxies. In the case of BaF2/Si, a BaSi2 compound has been identified previously. In the case of PbTe and CdTe, the heteroepitaxies on Si are made possible with the BaSi2 buffer. As a result, the impinging semiconductor molecules are broken up, and the metallic elements are ejected from the BaSi2 surface. A new surface chemical, BaTe, is thereby formed. These surface Ba compounds appear to be the dominant factors as the crystal orientations of the BaF2, CdTe, and PbTe layers are independent of those of the Si substrates.
Topographical Effects Regarding Trench Structures Covered with Rtcvd Sige Thin Films
Authors: Ritter G. , Schlote J. , Tillack B.
Published: March 2011

The paper presented discusses certain topographical effects being significant for the coverage of nonplanar structures with undoped and doped thin SiGe films. They are essential for new integrated heterojunction Si/SiGe devices. To investigate the coverage of topographical surfaces SiGe layers have been deposited on different trench structures in a Rapid Thermal Low Pressure single wafer CVD reactor (RTCVD) from the system SiH4, GeH4, and H2 using B2H6/ H2 and PH3/ H2 for the in-situ doping, respectively. Various deposition conditions and different film compositions have been used. The results especially the differences of the thickness distribution within trenches and on the surface have been discussed with regard to different CVD models taking into account distinguished reaction mechanisms.
Silicon Nucleation on Silicon Dioxide and Selective Epitaxy In An Ultra-High Vacuum Raptid Thermal Chemical Vapor Deposition Reactor Using Disilane In Hydrogen
Authors: Violette Katherine E. , Sanganeria Mahesh K. , Öztürk Mehmet C. , Harris Gari , Maher Dennis M.
Published: March 2011

Silicon nucleation on silicon dioxide and selective silicon epitaxial growth (SEG) were studied in an ultra high vacuum rapid thermal chemical vapor deposition (UHV-RTCVD) reactor. Experiments were performed using 10% Si2H6 in H2 in a pressure range of 10 - 100 mTorr at 760°C. Under these conditions, the growth rate ranged from 75 to 330 nm/minute. Loss of selectivity via Si island formation on SiO2 was studied using scanning electron microscopy (SEM) and atomic force microscopy (AFM) revealing a strong dependence on deposition pressure. Cross sectional transmission electron microscopy (XTEM) was employed to study the vertical oxide/epitaxy interface where faceting can occur. The incubation time for nucleation was found to increase from 10s to 70s as pressure is reduced from 100 mTorr to 10 mTorr, allowing thicker selective epitaxial film growth in spite of the reduced growth rates. This was attributed to the reduction in gas phase supersaturation of the Si containing species resulting in a lower density of adsorbed atoms on the SiO2 surface. This process shows a potential for chlorine free selective epitaxial growth and provides insight to the surface morphology of polycrystalline films deposited at low pressures.
Mombe Growth of Ybco Superconducting Films With In-Situ Monitoring of Rheed Oscillations
Authors: Endo K. , Teherani F. Hosseini , Yoshida S. , Kajimura K. , Moriyasu Y.
Published: March 2011

We have succeeded in in-situ growth of YBCO superconducting films by developing a new MOMBE technique which employs in-situ monitoring of RHEED intensity. The X-ray diffraction pattern showed peaks corresponding to those calculated from the Laue function which indicates the high quality of films grown using MOMBE. AFM and RHEED oscillations show 2-dimensional unit cell by unit cell growth.
Room Temperature Fabrication of Micro-Crystalline Silicon Films for Tft's By Ecr Pecvd
Authors: Jeon Yoo-Chan , Lee Seok-Woon , Joo Seung-Ki
Published: March 2011

Microcrystalline silicon films were formed at room temperature without hydrogen dilution by ECR PECVD. Microwave power more than 400 W was necessary to get crystalline films and the crystallinity increased with the power thereafter. Addition of hydrogen and argon enhanced the crystalline phase formation and the deposition rate, the reason of which was found that hydrogen etched silicon films and argon addition drastically increased the etch rate. Annealing of the films showed that microcrystalline silicon films formed by ECR PECVD have a small fraction of amorphous phase. TFT's using silicon nitride and doped/undoped microcrystalline silicon films were fabricatedd with whole processes at room temperature.
MOCVD Growth of Epitaxial SrTiO3 Thin Films on YBa2 Cu3O7−x/LaAlO3
Authors: Liang S. , Chern C. , Shi Z. Q. , Lu Y. , Lu P. , Kear B. H. , Safari A.
Published: March 2011

Strontium titanate (SrTiO3) thin films have been epitaxially grown on YB2Cu3O7−x (YBCO)/LaAlO3 at substrate temperatures of 660 to 700°C. X-ray diffraction (XRD) results indicated that single crystalline SrTiO3 thin films were epitaxially grown on the substrate with <100> orientation perpendicular to the substrates. The compositions of the films with different growth conditions were examined by Rutherford backscattering spectroscopy (RBS) and energy dispersive x-ray spectroscopy (EDX). The ratio of Sr/Ti is in the range of 0.9 to 1.1 for the films with a thickness of 1000–2000Å. The surface morphology of the films and the interfaces of the SrTiO3/YBCO structure were examined by scanning electron microscopy (SEM) and high resolution transmission electron microscopy (HRTEM). Very smooth surface and sharp interface were observed. The superconducting property of the YBCO layer, as measured by ac susceptibility, did not degrade after growth of SrTiO3 film. The dielectric constant as high as 320 was obtained at 100KHz. The leakage current density is less than 1×10−6A/cm2 at 3V operation.
Deposition of Titanium Oxide Films from Metal-Organic Precursor by Electron Cyclotron Resonance Plasma-Assisted Chemical Vapor Deposition
Authors: Nagahori Atsushi , Raj Rishi
Published: March 2011

Titanium oxide thin films were deposited at room temperature by the Electron Cyclotron Resonance Plasma-Assisted Chemical Vapor Deposition (ECR-PACVD) method. Effects of deposition temperature, microwave power and plasma gas pressure were investigated. Both Ar and O2 plasma were used to deposit films from titanium isopropoxide (Ti(OC3H7)4) precursor. Transparent titanium oxide films were obtained with O2 plasma. Refractive index and thickness were measured by ellipsometry and the films were characterized by x-ray diffraction.
Heteroepitaxial Si-ZrO2-Si by MOCVD
Authors: Greenwald Anton C. , Kalkhoran Nader M. , Namavar Fereydoon , Kaloyeros Alain E. , Stathakos Ioannis
Published: March 2011

The objective of this research was to demonstrate heteroepitaxial growth of yttria stabilized cubic zirconia on single crystal silicon substrates by chemical vapor deposition (CVD) using metalorganic source materials. We succeeded in depositing extremely smooth, well aligned films of zirconia on silicon substrates, both the <100> and <111> orientations, without an oxide interfacial layer. Experimental variables investigated included varying zirconia source materials, substrate temperatures, oxygen concentration, gas flow rates, yttria doping, substrate orientation, and cobalt-silicide as an oxygen diffusion barrier. ZrO2 films were predominantly tetragonal when deposited in the absence of oxygen while cubic phase material could be put down at 750°C with oxygen background. Films deposited from TMHD zirconium contained no measurable carbon contamination. Deposits from trifluoro-acetylacetonate Zr contained small amounts of fluorine, even in the presence of water vapor, and some carbon when hydrogen was used as a diluent gas.
Numerical Analysis of an Impinging Jet Reactor for the CVD and Gas-Phase Nucleation of Titania
Authors: Gokoglu Suleyman A. , Stewart G. D. , Collins J. , Rosner D. E.
Published: March 2011

We model a cold-wall atmospheric pressure impinging jet reactor to study the CVD and gas-phase nucleation of TiO2 from a titanium tetra-iso-propoxide (TTIP)/oxygen dilute source gas mixture in nitrogen. The mathematical model uses the computational code FIDAP and complements our recent asymptotic theory for high activation energy gas-phase reactions in thin chemically reacting sublayers. The numerical predictions highlight deviations from ideality in various regions inside the experimental reactor. Model predictions of deposition rates and the onset of gas-phase nucleation compare favorably with experiments. Although variable property effects on deposition rates are not significant (∼11% at 1000K), the reduction of rates due to Soret transport is substantial (∼75% at 1000K).
High Quality YBaCuO Thin Film Growth by Low-Temperature Metalorganic Chemical Vapor Deposition Using Nitrous Oxide
Authors: Zama Hideaki , Saga Jun , Hattor Takeo , Oda Shunri
Published: March 2011

Low-temperature growth of YBa2Cu3Ox films by metalorganic chemical vapor deposition using N2O as an oxidizing agent has been investigated. We have deposited superconducting YBa2Cu3Ox on (100)MgO substrates at 500°C for the first time. Films of 15nm-thick show zero-resistivity critical temperature of 80K. Films of as thin as three unit-cell-thick reveal the superconducting onset characteristics. This result suggests that superconductivity is arisen even from effectively monomolecular layer of YBa2Cu3Ox when we take into account monomolecular buffer layer and monomolecular cap layer. YBa2Cu3Ox films of 9nm-thick grown on (100)SrTiO3 at 600°C with Tc(zero) of 79K and with peak to valley roughness fluctuation of two unit-cell have been obtained.
Plasma Enhanced Metal-Organic Chemical Vapor Deposition of Germanium Nitride Thin Films
Authors: Hoffman David M. , Rangarajan Sri Prakash , Athavale Satish D. , Economou Demetre J. , Liu Jia-Rui , Zheng Zongshuang , Chu Wei-Kan
Published: March 2011

Amorphous germanium nitride thin films are prepared by plasma enhanced chemical vapor deposition from tetrakis(dimethylamido)germanium, Ge(NMe2)4, and an ammonia plasma at substrate temperatures as low as 190°C with growth rates >250 Å/min. N/Ge ratios in the films are 1.3 and the hydrogen contents are 13 atom %. The hydrogen is present primarily as N-H. The refractive indexes are close to the bulk value of 2.1, and the band gap, estimated from transmission spectra, is 4.8 eV.
Atomic Layer Controlled Deposition of Al2O3 Films Employing Trimethylaluminum (TMA) and H2O Vapor
Authors: Dillon A. C. , Ott A. W. , George S. M. , Way J. D.
Published: March 2011

Sequential surface chemical reactions for the controlled deposition of Al2O3 films were studied using transmission Fourier transform infrared spectroscopy (FTIR). Experiments were performed in situ in an ultrahigh vacuum UHV chamber using high surface area alumina membranes. Trimethylaluminum [Al(CH3)3] (TMA) and H2O vapor were employed sequentially in an ABAB... binary fashion to achieve atomic layer controlled growth. An optimal Al2O3 growth procedure was established that employed TMA/H2O exposures at .3 Torr and 500 K. The experiments revealed that each reaction was self-terminating and atomic layer controlled growth was dictated by the surface chemistry. The controlled deposition of Al2O3 may be employed on silicon surfaces for the formation of high dielectric gate and passivation layers.
Group 2 Element Chemistry and its Role in OMVPE of Electronic Ceramics
Authors: Rees William S.
Published: March 2011

Coordination compounds of alkaline-earth metals with simple monodentate ligands were mentioned in the literature as early as 1820, when Faraday reported ‘metal-ammonias’.[1] The number of heavy alkaline earth element coordination compounds remained limited for many years, however, as it was thought to be unlikely for the large earth alkaline cations to form such complexes. In 1967 Pedersen discovered that cyclic oligoethers (crown ethers) can serve as suitable ligands for divalent alkaline earth cations.[2] His findings were extended a few years later by Lehn who found that macrobicyclic multidentate ligands (cryptands) are efficient ligands for alkaline earth cations.[3] In each of these examples, the primary mode of metal-ligand interaction is electrostatic in origin. These examples demonstrate the lack of well-defined covalent bonding for Ca, Sr and Ba compounds. In the 25 years which have passed since Pedersen's seminal discovery, a large number of coordination compounds containing alkaline earth metals have been synthesized. In recent years, the emphasis has shifted towards the preparation of group 2 element-containing compounds which potentially can be used as precursors in the preparation of metal oxides by chemical vapor deposition [4–8]. In light of the general agreement that no “perfect” barium source presently exists for OMVPE purposes, this article will focus on general themes in group 2 element chemistry and, where relevant, correlate those themes within an integrated approach to design of new compounds of greater potential utilization for the preparation of electronic materials in thin film form.
Donor–Doped Lead Zirconate Titanate (PbZr1−xTixO3) Films
Authors: Desu Seshu B. , Vijay Dilip P. , Yoo In K.
Published: March 2011

Properties of undoped– and doped–ferroelectric PbZr1−xTixO3. films, with both Pt or RuO2 electrodes, were compared, with a view to understand the reasons for degradation of ferroelectric films. Donor–doped (e.g., Nb5+ at Ti4+ site) PbZr1−xTixO3 films, for which the PbO loss has been compensated, showed higher resistance to fatigue and low leakage currents compared to those of undoped films. The fatigue of ferroelectric films, a decrease in switchable polarization with increasing number of polarization reversals, has been attributed to the migration of oxygen vacancies and their entrapment at various interfaces (e.g., electrode/ferroelectric interface) that are present in the film.
Vapor Deposition of Lithium Tantalate with Volatile Double Alkoxide Precursors
Authors: Chour Kueir-Weei , Wang Guangde , Xu Ren
Published: March 2011

Stoichiometric vapor deposition of LiTaO3 is demonstrated by thermal evaporation of volatile LiTa(OButn)6, controlled vapor phase partial-hydrolysis, and subsequent polycondensation reactions on a heated substrate surface. Fully dense, amorphous LiTaO3 film of up to 34 μm thick can be obtained at high deposition rate of 23 μm per hour. Single phase LiTaO3 films are obtained by annealing as deposited films. The vapor phase species responsible for the stoichiometric vapor deposition appeared to be Li2Ta2(OButn)12 from variable temperature mass spectrometry results.
Investigation of Second Harmonic Generation in MOCVD Grown Barium Titanate Thin Films
Authors: Bihari Bipin , Jiang Xin Li , Kumar Jayant , Stauf Gregory T. , Van Buskirk Peter C.
Published: March 2011

Ferroelectric Barium titanate (BaTiO3) thin films have potential applications in optical devices such as frequency doublers. Second harmonic generation (SHG) in MOCVD grown epitaxial thin films of BaTiO3 on MgO substrates is reported at an incident wavelength of 1.064 microns. A number of as-grown films show substantial second harmonic signal. Angular dependence of second harmonic intensity from as-grown films reveals that the orientation of the c-axis in these films are dependent on the growth conditions. We have examined the effect of heating and corona poling on the second harmonic generated by the samples. A higher level of SHG was observed during application of the electric field. On the removal of the poling field the second harmonic signal relaxes back. This behavior may indicate substrate-induced strain stabilization of domains.
Solidification Morphology of Cast Irons
Authors: Rickert A. , Engler S.
Published: March 2011

The solidification morphology dictates the type of crystal growth for crystallites during solidification. As a result of this process, the casting may be unsound due to the presence of shrinkage cavities, internal shrinkage, sinks and hot tears. Therefore, it is important to have a knowledge of the solidification process to avoid these defects and to produce a sound casting.
Graphite Formation in Low Carbon Silicon Cast Irons
Authors: Chakrabarty A. K. , Kondic V. , Young J. M.
Published: March 2011

SYNOPSIS

The conditions were studied under which either eutectic graphite or carbide or both, Can form during freezing in low carbon silicon irons. Experimental variables included: iron composition, (C 1.32 to 2.17, Si 1.56 to 2.35%) small additions of alloying elements, (Ca, Mg, Al, S arid 0) and cooling rate (varying from quenching to slow cooling).

Thle results obtained show that without any alloying additions these irons solidify witb the formation OF eu~tectic carbide. A fully graphitic cast structure can he readily obtained, however, with inoculating additions of either Ca or Mg. The inoculating potential of these elements increases in the presence of small amounts of Al ard 0, hut decreases with the addi tion of S. Bal ancing S with Mn restores and improves graphite nucleation by other elements. Both Ca and Mg promote spherulitic, whilst Al and high C levels, promote flake graphite morphologies. Conditions and mechanisms of formation of euitectic graphite or carbides or their mixtures in low carbon and silicon cast. irons are discussed in thle light Of current theories of solidi ficati on of east irons.
A Computer-Aided Simulation of the Kinetics of Solidification of the Eutectic Ductile Cast Iron
Authors: Edward Fras
Published: March 2011

An attempt has been made to construct a model of the solidification of the globular eutectic grains which would account for an effect of interblocking the grain growth and would enable calculations starting with the pouring temperature and proceeding until the complete solidification of a casting is obtained. The family of equations proposed in this work enables a simulation of the kinetics of the transformation using a computer and basing only on the knowledge of the materials-designing properties of a foundry mould and the technological parameters of cast iron. The examples of computations given in the paper and the discussion of the results obtained makes it possible to explain the effect of various technological factors on the course of the solidification kinetics of a casting in the cause-effect relation.
SG Cast Iron – Influence of Hot Shakeout on the Microstructure Obtained through Varying Heat Treatments
Authors: Schissler J. M. , Saverna J. , Bellocci R. , Bak C.
Published: March 2011

As heat treatments of metallic alloys generally require high temperatures, energy saving cycles are increasingly looked for. Castings offer the advantage over wrought products of possible hot shake out as they are just made.

The object of this study was to observe the structure of a SG cast iron resulting from hot shakeout right after the end of solidification, followed or not by a 1 000°C holding and subsequent heat treatment.

The austenite then presents the peculiarity of not having been re-generated by heating up from an initial structure as it is the case in conventional cycles.

This study has clearly showed the influence of composition heterogeneity within the solidification cell on the response to heat treatment. Along the solidification cell boundary, an increase in carbon and manganese contents was found while silicon decreased. Along the SG nodules, the opposite is true. Between these two zones, gradients vary. The presence of these three areas results in having three different CCT curves and, therefore, a varying response to heat treatment. This is even magnified by the section size of the sample because the cell size increases, but this is minimized by the decrease in quenching rate.

Structural differences observed in hot shake out samples and re-heated samples, both held or not at 1 000°C, and then cooled down, are directly related to these composition heterogeneities:

- hot shakeout cast iron shows a high hardenability which varies with the holding time at 1 000°C;

- after a ferritizing treatment, an homogeneous matrix is difficult to obtain from a hot shakeout cast iron;

- after austempering the structural heterogeneity of the cell boundary is greater for the hot shakeout cast iron;

- after the pearlitic transformation, the structure of the hot shakeout cast iron is similar to that resulting from conventional treatment.
Irreversible Carbon Diffusion in Growth of Cast Iron
Authors: Nagaoka K. , Souma M.
Published: March 2011

In gray cast iron carbon diffuses irreversibly and the result is a growth remaining castoff voids and graphite redistribution. The origin of primary growth is in the mechanism of carbon diffusion which is controlled by a ratchet at graphite where carbon is carried by vacancy flow. Growth of flake cast iron in oxygen reduced air at low oxygen content is accounted for by self carburizing due to a reaction of penetrated oxygen and graphite flakes. For the irreversible carbon migration by gaseous carrier another ratchet is suggested. Cracking theory for primary growth is replaced by castoff void theory, and oxidation theory is modified.
The Effect of the Structure and the Heating and Cooling Rate on the Thermal Expansion of Grey Cast Iron
Authors: Sunnerkrantz P. A. , Fredriksson H.
Published: March 2011

The thermal expansion of grey cast iron was studied in six different alloys. The expansion was determined at two different heating and cooling rates. It was found that the expansion was influenced by the heating and cooling rates. The thermal expansion was larger than the thermal expansion in steel and the thermal expansion also increased with increasing temperature. The thermal expansion was theoretically analysed. The temperature dependence was accounted for, by considering the fact that the carbon content in austenite and ferrite increases with increasing temperature.
Austempered Ductile Cast Irons–Influence of Microstructure Control
Authors: Voigt R C. , Loper C. R.
Published: March 2011

The influence of microstructure on the properties of austempered ductile cast irons have been studied along with an analysis of the necessary process control to insure consistent properties. Both austempered ductile iron transformed at high temperatures with a matrix structure of carbide-free ferrite and substantial amounts of austenite, and austempered/bainitic ductile iron transformed at low temperatures with a more characteristic bainitic structure also containing austenite have been studied. The good toughness and ductility of these high strength ductile irons is due to the microplasticity associated with both the ferrite and austenite phases; however carbide precipitation during the later stages of austempering reduces room temperature toughness considerably and results in a change to a quasi-cleavage fracture mode. The influence of casting quality control and heat treatment control on the microstructures and properties obtained are discussed.
Transformation Behavior in Austempering Nodular Iron
Authors: Gundlach R. B. , Janowak J. F. , Bechet S. , Röhrig K.
Published: March 2011

Interest in austempered bainitic ductile irons has increased dramatically in the past few years as more and more successful applications are being reported. The remarkable combination of properties attainable has caused this material to emerge as a new class of ductile iron. Austempered ductile irons achieve strength levels as high as twice those of standard ductile iron grades at the same level of toughness and ductility, see Figure 1. In addition they respond to work-hardening treatments at the surface and thus have exceptionally high bending fatigue strength and wear resistance. These good properties are directly related to the unique bainite-austenite microstructure produced by austempering.
Influence of Silicon on Bainite Transformation in Ductile Iron; Relation to Mechanical Properties
Authors: Nieswaag H. , Nijhof J. W.
Published: March 2011

Using a dilatometer the isothermal transformation of austenite to bainite has been studied in ductile cast iron with 0.05 % Mn and a silicon content varying from 2.4 to 3.8 %. The alloys were austenitized to a carbon content in the matrix of 0.65 %. It appears that silicon retards the formation of carbides in the upper bainite region (400 °C), resulting in an amount of retained austenite up to 40 % present in the final structure at room temperature. Silicon improves the strength; in the lower bainite region the yield strength in particular. An elongation up to 10 % or more is obtained after austempering at 400 0C independent of the silicon content.
Contribution to the Solidification and Graphitization Behavior of Sand-Cast and Gravitiy Die Cast Malleable Iron
Authors: Doepp Reinhard
Published: March 2011

Structure and properties of whitoheart malleable iron cast in gray iron permanent molds are examined. The results of test bars and industrial castings are compared to those of green sand molds. Malleable iron is predestined for casting in permanenet molds, because it must solidify completely white. Faster cooling achieved Dy the permanent mold refines primary austenite dendrites, promotes formation of ledeburite (metastable eutectic) and allows higher contents of graphitizing elements. Silicon content can be raised. The yield improves, annealing time decreases, combination of mechanical properties is improved. Combined metallurgical, technological and environmental advantages can improve economy.
The Relationship between Tensile Strength and Microstructure in Flake Graphite Cast Iron
Authors: Castillo R. N. , Baker T. J.
Published: March 2011

The effects of composition and process variables on the tensile strength of flake graphite cast iron are well established. However, when compared with most metallic materials, there is little quantitative understanding of the way in which the microstructure controls the mechanical properties. In this paper a fracture mechanics approach is used to develop a mechanistic interpretation of the relationship between the microstructure and tensile strength. Flake graphite cast irons have been studied in which matrix microstructures of pearlite, ferrite and tempered martensite have been developed by heat treatment. For a given eutectic cell size, a linear relationship exists between the tensile strength and the fracture toughness KIC, for all of the matrix structures studied. The tensile strength is interpreted as a brittle fracture stress which is determined by the fracture toughness of the iron and an inherent defect size which is defined by the eutectic cell size.
The Role of Graphite Nodules in the Deformation Behaviors of Spheroidal Graphite Cast Iron
Authors: Sumimoto Haruyoshi , Nakamura Kokichi
Published: March 2011

When a ferritic Spheroidal Graphite Cast Iron(SG iron) is submitted to a large tensile load, the graphite nodules in the iron are deformed into oval shape. It has been recognized that a large deformation under tensile stress produces a kind of voids at the graphite edges. However, the breaking process of the graphite nodules has not been clarified yet.
Tensile Deformation of Cast Iron During Pearlite :Austenite Transformation
Authors: Hazotte A. , Simon A.
Published: March 2011

Remarkable elongations have been obtained on cast iron samples subjected to alternate thermal cycles around the A1critical point, under a tensile stress lower than the yield stresses of the stable phases. This procedure makes use of the “phase transformation plasticity”, characterised by an apparent softening of the material during its structural evolution. The influence of the applied stress, as well as the heating and cooling rates,on the elongation per cycle has been studied. A quantitative comparison between this “soft” technique and the more classical high-temperature metal forming techniques (deformation in stable α or γ domains, or in α + γ domain, high temperature creep) showed that, for an equal strain, the internal cavitation resulting from the thermomechanical cycling deformation of spheroīdal graphite cast iron is much smaller than for other techniques. This soft technique leads to higher mechanical characteristics at room temperature.
Spatially and Temporally Resolved Reflectivity Profiles of
Crystalline Silicon Irradiated by 48 Ps Pulses of One-Micron Laser
Radiation
Authors: Moss Steven C. , Boyd Ian W. , Boggess Thomas F. , Smirl Arthur L.
Published: March 2011

Time-resolved reflectivity measurements have been performed on
single-crystal silicon irradiated by intense 48 ps pulses of 1 micron
radiation. The temporal evolution of the spatial profile of the
laser-induced reflectivity changes has been monitored using spatial
correlation and surface imaging techniques. These measurements resolve
apparent discrepancies between previous spatially and temporally averaged
measurements at this wavelength and similar measurements in the visible.
Time-Resolved Ellipsometry and Reflectivity Measurements of the
Optical Properties of Silicon During Pulsed Excimer Laser Irradiation
Authors: Jellison G. E. , Lowndes D. H.
Published: March 2011

Several advances in time-resolved optical measurement techniques have been
made, which allow a more detailed determination of the optical properties of
silicon immediately before, during, and after pulsed laser irradiation. It
is now possible to follow in detail the time-resolved reflectivity signal
near the melting threshold; measurements indicate that melting occurs in a
spatially inhomogeneous way. The use of time-resolved ellipsometry allowed
us to accurately measure the optical properties of the high reflectivity
(molten) phase, and of the hot, solid silicon before and after the laser
pulse. We obtain n = 3.8, k = 5.2 (±10.1) at λ = 632.8 nm for the high
reflectivity phase, in minor disagreement with the published values of
Shvarev et al. for liquid silicon. Before and after the high reflectivity
phase, the time-resolved ellipsometry measurements are entirely consistent
with the known optical properties of crystalline silicon at temperatures up
to its melting point.
Laser-Beam-Glass Interaction Inducing Glass-Crystalline
Transformations
Authors: Haro E. , Balkanski M. , Espinosa G. P. , Phillips J. C.
Published: March 2011

In recent years GeSe2 glass has been intensively studied by
different methods. Light scattering experiments [1–10] have been used to
investigate the molecular structure of the chalcogenide glasses. Diffraction
studies [16–17] have shown that the short range order of this glass is
similar to that of the crystalline GeSe2. Raman [9–10] and
Mössbauer [11–15] spectroscopies have extended these results to include
large number of atoms (intermediate range order). Glass-crystalline
transition induced by laser irradiation has been investigated essentially by
Raman scattering [10–16].
Electron Beam Annealing of Phosphorus Implanted Cadmium
Telluride
Authors: Yang C.B. , Peng M.L. , Lue J.T. , Hwang H.L.
Published: March 2011

The behavior of dopants in CdTe has been examined by Krogen and DeNobel and
others. The n-type material is easy to dope with good electrical activity.
The p-CdTe is more difficult to produce with concentration higher than
6×1016 cm-3. For doping levels above this, the
electrical activity of the dopant drops sharply and the hole mobility is
reduced. The difficulty in doping p-CdTe stems from both strong compensation
effects and low solubility of the usual dopant species.

The electron beam pulse method has been applied to annealing phosphorus
implanted cadmium telluride. The threshold electron beam energy density
necessary to give good electrical activation and mobility have been
established in the range between 9.2-10.1 J.cm-2 for doses from
1014-1016 ions cm-2. A sheet resistance
as low as 6.32×10 Ω/  and a carrier concentration as high as
3×1018 cm-3 have been obtained. The impurity
profile of the annealed samples have been obtained by etching layer by layer
with the etching rate calibrated by chemical techniques and the impurity
concentration determined by van der Pauw/Hall technique.
Threshold Energies for the Melting of Si And Al during
Pilsed-Laser Irradiation
Authors: Ong C.K. , Tan H.S. , Sin E.H.
Published: March 2011

The heat flow calculations have been performed to obtain the threshold
energies for the melting of Si and Al during pulsed-laser irradiations under
various laser conditions. The temperature dependent optical and thermal
properties of the solids are deduced from the available experimental data.
The melting threshold energies calculated for the solids are within the
accuracy of the experimental values.
Implanted Impurity Incorporation and Segregation Phenomena
Induced by PEBA in Silicon
Authors: Chaussemy G. , Barbier D. , Laugier A.
Published: March 2011

In this work, the PEBA induced thermal effects have been varied to study the
diffusion of usual implanted impurities (P, As, Sb, In) and segregation
phenomena in (100) and (111) silicon. The mean melt-front velocity has been
adjusted between 1 and 4 m/s by modifying both the beam fluence and the
sample starting temperature. A model for dopant redistribution has been
developped, using a mean diffusion coefficient D and solving the one
dimensional Fick's equation. Segregation and dopant evaporation are
considered and introduced as limit conditions at the liquid-solid interface
and at the wafer surface respectively. The impurity redistribution has been
experimentally studied by SIMS profiling ; so that interfacial segregation
coefificient Ki may be deduced from comparison between experimental and
computed profiles.
Electronic Defects in Transient, Thermally Processed
Semiconductors
Authors: Johnson N.M.
Published: March 2011

This paper summarizes the general observations that may be drawn from
numerous studies of electronic defects in transient thermally annealed bulk
single – crystal silicon and discusses the emerging subjects of electronic
defect evaluation in beam – crystallized silicon thin films and in
epitaxially – grown III – V semiconductors.
Activation of Si-N Modes in Silicon by Pulsed Laser
Annealing
Authors: Stein H. J. , Peercy P. S. , Hills C. R.
Published: March 2011

Retention and bonding of nitrogen implanted into crystalline Si were
examined by infrared absorption (ir) and transmission electron microscopy
(TEM) after furnace and pulsed laser annealing. Localized Si-N vibrational
modes for N-N pairs are observed, and the associated ir band intensities
increase upon pulsed annealing. Furnace annealing above 600°C decreases the
ir intensity for N-N pairs and fine structure defects appear in TEM.
Subsequent laser annealing removes most of the fine structure and
reactivates the pair spectrum which we interpret as dissolution of N
precipitates and pair formation upon quenching from the melt. Any realistic
model for N in Si must include the formation and consequences of N-N
pairs.
A Comparison of Millisecond Annealing of B Implants and
Isothermal Annealing for Times of a Few Seconds
Authors: Mcmahon R. A. , Hasko D. G. , Ahmed H. , Stobbs W. M. , Godfrey D. J.
Published: March 2011

The annealing behaviour of B implants in the millisecond time regime using a
combination of swept line beam and background heating is compared with
isothermal annealing with heating cycles of a few seconds. Carrier
concentration profiles derived from spreading resistance measurements show
that under annealing conditions which restrict diffusion, millisecond
processing gives higher activation of B implants than isothermal heating.
Transmission electron microscopy shows that millisecond annealing also
results in a lower defect density than that following an equivalent
isothermal anneal.
Transient Annealing of Neutron-Transmutation-Doped
Silicon
Authors: Pollard C J , Barraclough K G , Skolnick M S
Published: March 2011

Scanning electron beam annealing has been used to study the annealing of NTD
silicon in the temperature range 600-1180°C. The annealing process has been
found to be very rapid above 800°C, a 30 second anneal producing highly
uniform n-type material. Below this temperature, an initial drop followed by
a progressive rise in sample resistivity with increasing anneal time is
consistent with phosphorus dopant activation and the formation of a
defect-related acceptor complex.
Dopant Incorporation in Silicon During Nonequilibrium
Solidification: Comparison of Two Processes
Authors: Fogarassy E.P. , Lowndes D.H. , Narayan J. , White C.W.
Published: March 2011

The incorporation properties of implanted or deposited Sb into the silicon
lattice during laser irradiation with a UV laser has been studied. For both
implanted or deposited Sb, we find a maximum substitutional concentration of
2.1 × 1021/cm3 following laser melting and
solidification at V ; 6 m/sec. In both cases, substitutional solubility is
limited by inter-facial instabilities which develop during regrowth. For the
deposited case we observe in addition a much larger cellular microstructure
which may result from convection induced instabilities.
Boron Redistribution During Transient Thermal Metal Silicide
Growth on Si
Authors: Sofield C.J. , Harper R.E. , Rosser P.J.
Published: March 2011

We have used the heavy ion elastic recoil technique to study B distribution
changes during Co and Ti di silicide formation on B implanted single crystal
Si wafers. B diffuses to the interface of TiSi2 and Si and to the
surface of CoSi2.
Titanium Silicidation by Halogen Lamp Annealing
Authors: Okamoto T. , Shimizu M. , Tsukamoto K. , Matsukawa T.
Published: March 2011

Silicidation of titanium on silicon is carried out with the halogen lamp
annealing. It is found that the lamp annealing is quite effective in forming
an oxide-free and homogeneous titanium disilicide layer with resistivity of
15–17 μohm·cm. Rutherford backscatterring and X-ray diffraction studies show
that the halogen lamp annealing over 650 °C for only 60 sec results in
disilicide. By a silicidation reaction, arsenic and boron atoms at silicon
beneath a titanium layer are incorporated into a formed silicide layer.
Arsenic atoms initially in a titanium layer are swept toward the surface as
silicidation reaction proceeds. Arsenic atoms in titanium have an effect to
retard silicidation reaction.
Luminescence of Si-Implanted InP After Rapid Thermal
Annealing
Authors: Kirillov D. , Merz J. L.
Published: March 2011

Changes in the luminescence spectra of InP caused by Si+
implantation and subsequent rapid lamp annealing were studied. It was found
that the best activation of dopants was obtained in the case of hot
implantation and lamp annealing in regimes close to melting of InP.