bluuebunny/crossref_metadata_2025_split huggingface dataset:
Optical Waveguide Fabrication by Stoichiometric Implantation of Ti and O into LiNbO3
Authors: Pokers D. B. , Xia W. 
Published: March 2011

ABSTRACTX-cut substrates of LiNbO3 have been implanted at 500°C with Ti and O to doses of 2.5 and 7.5×l017 ions/cm2, respectively. The high substrate temperature during implantation ensures dynamic recrystallization, preserving the crystallinity of the LiNbOs-The stability of the stoichiometric implants is enhanced sufficiently that annealing at 1000°C proceeds with no surface degradation of the substrate. Annealing under identical conditions without the 0 implant usually results in phase separation of an oxide at the surface, even when annealing is performed immediately following implantation. Samples implanted with Ti and O to preserve the stoichiometric metahoxygen ratio of the substrate can be stored at room temperature for several months without phase separation. Planar optical waveguides have been produced by stoichiometric implantation followed by annealing in water-saturated oxygen for one hour at temperatures of 900 and 1000°C. The sample annealed at 900°C supported a single lossy mode, while the 1000°C sample supported two propagating modes and one lossy mode at λ=0.6μm.
Ion Implantation-Induced Amortization of Ceramic Oxides
Authors: Pedraza D.F. 
Published: March 2011

ABSTRACTA mechanism of amorphization by ion implantation in ceramic oxides is studied using a rate theory approach. It is proposed that the production of highly localized lattice distortions causes lattice destabilization and the ensuing transition to the amorphous state. These distortions can be caused by a large point defect buildup. It is argued that point defect retention occurs because of the impossibility of producing antisite defects. It is proposed that point defects on each sublattice can shield or trap point defects on the other sublattice. Similarly, metallic impurities may shield oxygen vacancies or trap oxygen interstitial ions, preventing anion Frenkel pairs from recombining. These effects are modeled in a-alumina for low temperature implantations (e.g., around 78 K), where point defects are immobile. It is shown that, at these temperatures, recombination is strongly hindered by the radiation-induced point defects themselves, rather than by the implanted impurities. The high point defect concentration attained by this mechanism is sufficient to raise the free energy of the crystal above the free energy of the amorphous solid.
Ion Implant Activation and Redistribution in AlxGa1–xAs
Authors: Pearton S. J. , Hobson W. S. , Von Neida A. E. , Haegel N. M. , Jonesf K. S. , Morrisft N. , Sealytt B. J. 
Published: March 2011

ABSTRACTThe electrical activation characteristics of implanted Be, Mg, Si and S in AlxGa1–xAs (x = 0-1) were investigated as a function of ion dose for rapid annealing in the range 600-950°C. The apparent activation energy for electrical activity of these species increases with increasing AlAs mole fraction - for Be, the activation energy is 0.35eV for GaAs and 0.49eV for Al0.54Ga0.46 As. There is no evidence for pairing of Be and O in AlGaAs, in contrast to the situation for GaAs. Self-compensation is the predominant limiting mechanism for Si activation in AlGaAs as determined by the relative photoluminescence intensities of the SiGa-to-SiAs related transitions. No significant redistribution of implanted Si is observed for any AlAs mole fraction for rapid annealing (5 sec) up to 900°C, whereas S shows motion into the AlGaAs and no tendency to outdiffuse. By contrast, both Be and Mg display loss of the dopant to the surface, and little redistribution toward the bulk. Minimal damage is observed by transmission electron microscopy in as-implanted AlGaAs for Be or Si doses below the amorphization threshold. Upon annealing at the conditions for optimum activation, a high density of small dislocation loops is observed near the end of the ion range.
The Structure and Properties of Ni Films Grown By Ion Beam Assisted Deposition
Authors: Kant R.A. , Chambers G.P. , Sartwell B.D. 
Published: March 2011

ABSTRACTElectron-beam evaporated nickel was deposited onto sapphire or rocksalt substrates at room temperature with and without simultaneous argon ion bombardment. The ion energies were 100, 500, or 1500 eV, with ion-to-atom arrival ratios, R, ranging from 0.01 to 0.1. For each film, the microstructure, density, resistivity, and amount of retained argon was measured. It was determined that 100 eV bombardment produced an increase in density with little change in resistivity, whereas 1500 eV bombardment decreased the density and increased the resistivity monotonically with R. The reduction in density was correlated with decreasing microstructural feature size and decreased preferred orientation which suggested that the ions induced an increase in the volume fraction of boundaries.
Ion Channeling Measurements on Germanium Implanted and Annealed Silicon
Authors: Johnson E.A. , Namavar F. , Cortesi E. , Culbertson R.J. 
Published: March 2011

ABSTRACTWe have prepared GexSi1-x/Si structures by implanting germanium into silicon <100> surfaces and thermally annealing. Implant energies were 100 and 150 keV and the total ion doses were between 1 and 10 × 1015 ions/cm2. Ion channeling studies of these structures indicates that after annealing, the germanium atoms substitute into the silicon lattice and create a pseu-domorphic strained layer. In addition, channeling results suggest a residual band of dislocations at or beyond the ion range in the as-annealed samples.
Ion Implantation Induced Effects at Polysdlicon Gate Feature Edges
Authors: Stinson M. G. , Smith P. L. , Osburn C. M. 
Published: March 2011

ABSTRACTRecently, an enhanced leakage associated with ion implantation at polysilicon gate edges has been reported (1). In this study, TEM and SIMS characterization have been done to supplement electrical measurements in order to better understand the degradation. SIMS, XTEM, and TRIM analyses of arsenic implants through 7 nm gate oxides show considerable ion mixing. A roughening of the underlying silicon substrate leads to asperities which are believed to play an important role in enhancing leakage (2). XTEM analysis of a polysilicon gate edge also reveals the effects of volume expansion associated with the incorporation of both dopant and knock-on oxygen.
Rbs Studies of Damage Behavior in Silicon Induced By P2+ Implantation
Authors: Genqing Yang , Chenglu Lin , Ziwei Fang , Zuyao Zhou , Shichang Zou 
Published: March 2011

ABSTRACTThe damage behavior of <100>-Si implanted with P2+ and P+ ions at equivalent energies were investigated by 2MeV He* backscattering and channeling analysis. Different incident energies (25-90keV/atom) and intermediate doses (1013–1014/cm2) were used for the implantation with sample holder being kept at temperatures ranging from 77k to 483K. It has been shown that the damage created by P2* implants is always greater than that of P2+ implants when the dosage is below the threshold fluence at which amorphization takes place. This damage enhancement phenomenon is strongly related to implantation temperature. A striking damage enhancement induced by 90 keV/atom P2+ implants in the surface region of the sample was observed, and it has been attributed to the multiple collision effect between diatomic ions and host atoms.
Concentration Dependence of Arsenic on Solid Phase Epitaxial Regrowth of Amorphous Silicon
Authors: Jeon Young-Jin , Becker M. F. , Walser R. M. 
Published: March 2011

ABSTRACTIn this work we measured the functional dependence of the solid phase epitaxial (SPE) regrowth rate, V, of amorphous silicon on the concentration of implanted arsenic (n-type) impurity, NAs. The SPE regrowth rates of self-ion amorphized layers in silicon wafers with (100) substrate orientation were measured by in situ, high precision, cw laser interferometry during isothermal annealing for temperatures from 470 °C to 580 °C, and concentrations in the range 1.5×1018cm−3 ≤NAs≤3.5×1020 cm−3.In the concentration range 7×1018 cm−3≤NAs≤2.2×1019 cm3, selected from the medium dose sample, the SPE regrowth data satisfied a linear equation; V/Vi=1+NAS/Ni, where Ni(T) was fit to an Arrhenius form obtained from the temperature dependent intersections of the SPE regrowth rate data with the concentration axis and Vi(T) was the temperature dependent apparent intrinsic SPE regrowth rate at zero impurity concentration. A similar linear dependence was obtained earlier for boron (B) and phosphorus (P).However, unlike B and P, an enhancement of SPE regrowth was observed for samples implanted with As in the concentration range 3×1018 cm−3 ≤NAS≤ 1.3×1019 cm−3, selected from the low dose sample. This result indicates that arsenic implanted at low dose levels has a higher fractional ionization in amorphous silicon than either boron or phosphorus implanted at the same dose.In the high dose samples with arsenic concentrations ≤NAs 2.2×1019 cm−3, the SPE regrowth rate varied nonlinearly with NAS. The nonlinear function had a negative curvature similar to that observed previously for P.
The Effect of Microstructure in the Morphology and Kinetics of Amorphization Induced by Ion Irradiation
Authors: Pedraza D.F. , Maziasz P.J. 
Published: March 2011

ABSTRACTNiTi was irradiated with Ni ions to study the rate of amorphization as a function of temperature and to determine the temperature cutoff for the crystalline-to-amorphous transition. A series of irradiations was conducted at different temperatures from ambient to 350 °C. Prior to irradiation, the specimens contained martensitic plates and austenitic (B2) regions. However, during irradiation at temperatures of 80 “C and higher, all the specimens were entirely austenitic. As expected, amorphization was delayed as the irradiation temperature was increased. The fraction of material that became amorphous after irradiation at 250 °C to a dose of 0.7 dpa was estimated to be 5 to 10%. Specimens irradiated at higher temperatures remained crystalline, even after doses as high as 4 dpa. Irrespective of the irradiation temperature, we found a non-uniform distribution of amorphous regions that exhibited a morphology closely resembling the shape of the martensitic plates that existed in the material prior to heating it to the irradiation temperature. These observations are discussed in terms of the influence of structural defects on the kinetics of amorphization.
Metastable Phase Formation in the Ti-rich end of the Ti-(Co,Ni) System
Authors: Lilienfeld David A , Bergesen Peter 
Published: March 2011

ABSTRACTThe Ti-rich end of the Ti-(Co,Ni) was investigated by ion mixing. A metastable FCC phase was discovered which formed over a broad composition range. The stable phase was formed by ion mixing at 350°C in some samples but was not formed until 550°C during in situ heating in the Transmission electron microscope. Some of the Ni-rich ternary alloys did not amorphize even after liquid nitrogen ion irradiations. This result indicates that the amorphization mechanism for the TiNi CsCl phase is different from that of the TiCo CsCl phase.
Study of Hf Diffusion in A-Zr using Rutherfdrd Bacckscrttering Spectroscopy
Authors: Dyment F. , Behar M. , Oners H. , Grande P.L. , Savino E. , Zawislak F.C. 
Published: March 2011

ABSTRACTThe present contribution reports on measurements of the diffusion coefficients of Hf in a-Zr via the RBS technique. 250 8 Hf thin films were deposited on two kinds of polycrystalIine Zr samples and annealed in a 773-1115 K temperature range. Our results show that in both cases, the diffusion coefficients follow curved flrrhenius plots. On the other hand for the purest Zr sample we have obtained diffusion coefficients that are systematicaly and significativel ly lower than those corresponding to the Zr sample richer in impurities.
Metastable Structures Formed in Plasma Source Ion Processing
Authors: zheng Xiao-Ci , Dodd R. A. , Conrad J. R. 
Published: March 2011

ABSTRACTNi-Ti films were bombarded by plasma source heavy ions of different ion dose and ion flux. Disc-like non-uniform microstructures were found when the films were irradiated at a dose of 5x1016Kr+/cm2. These “discs” were acting as defect centers. The development of “discs” depended on the plasma ion flux during the pulse. Target geometry appeared to have effects on the density of “discs”.
Residual Stress in and Microstructure of Fe and Ti Surface Layers After 1 Mev N+ Implantation at High Dose
Authors: Vredenberg A.M. , Saris F.W. , Pers N.M. v.d. , Colijn P.F. , de Keijser Th.H. , Mittemeijer E.J. 
Published: March 2011

ABSTRACTThe effect of 1 MeV N+ irradiation on the microstructure of Fe and Ti specimens was investigated. The Fe and Ti specimens were implanted such that the N peak concentration (30 at.% in Fe, 45 at.% in Ti), was below the concentration of N in ε-Fe2N and δ-TiN, respectively. X-ray diffraction phase analysis showed that ε-Fe2N and δ-TiN had formed. X-ray diffraction stress analysis indicated that the residual stress in the Fe and Ti matrices was negligible after implantation. This suggests that the volume misfit due to nitride formation had been accommodated by plastic deformation. Indeed, surface profilometry of implanted Fe showed that a volume increase of the specimen had occurred which was compatible with the formation of unstrained nitride .
On the Stability of Hetastable and Amorphous Pvd-Compound Films
Authors: Knotelc Otto , Jungblut Frank , Barimani Arman 
Published: March 2011

ABSTRACTIn using low temperature physical vapour deposition (PVD) techniques new metastable and amorphous materials can be deposited. Structural order in a coating is produced largely by the mobility of the adatoms. Low mobility does not allow the formation of equilibrium phases and metastable and/or amorphous structures are observed. These coatings have sufficient thermal stability for tools, and for both wear- and corrosion-protection. Examples are given within the systems Al-O-N, Ti-Al-N and Cr-Al-N and the properties, crystalline and thermodynamic state of the coatings are characterized. An example of decomposition phenomena is given in metastable thin coatings by the Ti-Zr-N system.
Excimer Laser Induced Deposition of Tungsten from W(CO)6 and WF6
Authors: Rager Berthold , Bachmann Friedrich 
Published: March 2011

ABSTRACTArF laser induced deposition of W from W(CO)6 and WF6 on Si/SiO2 surfaces was investigated. With an in-situ reflectivity measurement the growth of the layer could be monitored during the deposition process. We find that the initial stage of layer growth as well as the reflectivity as a function of deposition time depends on the laser fluence and on other deposition parameters. Model calculations, using the optical constants of deposited films, determined by ellipsometry, have been performed to compare the measured reflectivity curves with the calculated curves. The deposited layers have been analyzed by XPS, AES, X-ray Diffraction and Raman Spectroscopy. Additionally, experiments of direct pattern transfer deposition (via contact mask) with W(CO)6 show the presence of an involved surface process, which by Fresnel diffraction caused structures smaller than 0.5μm.
Roles of Gas Phase and Surface Photolysis in Laser Chemical Vapor Deposition from Fe(CO)5
Authors: Xu Xin , Steinfeld J.I. 
Published: March 2011

ABSTRACTThe chemical state of the carbon and oxygen incorporated in iron films formed by laser photolysis of Fe(CO)5 has been examined by profiling XPS analysis. A significant portion of the codeposited CO is photodissociated at the growing surface.
Metal Deposition with Incoherent Excimer Radiation
Authors: Esrom Hilmar , Kogelschatz Ulrich 
Published: March 2011

ABSTRACTVUV light-induced decomposition of palladium acetate films was performed by using a new incoherent excimer source. With pure xenon this excimer source emits radiation peaking at a wavelength of 172 nm. We investigated mainly the palladium deposition from spin-on palladium acetate films on aluminum oxide substrates. By using EMP we determined the palladium thickness as a function of UV intensity and exposure time. A remarkable temperature effect of the photolytic deposition process was observed also in a temperature range in which no thermal decomposition is possible. The exposure of spin-on palladium acetate films on ceramic substrates was also accomplished through metal contact masks. Patterned palladium films were reinforced by electroless copper and nickel plating processes [1]. The obtained structures had the same high edge quality as those produced by using excimer lasers [2].
Electronic Excitation-Induced Surface Chemistry and Electron-Beam-Assisted Chemical Vapor Deposition
Authors: Bozso F. , Avouris Ph. 
Published: March 2011

ABSTRACTSelective area deposition of thin films and surface structures with precise control over their composition is possible in UHV by using low energy electron beams to induce electronic excitations in adsorbed molecular layers. Upon electron impact, adsorbed/co-adsorbed molecules decompose into reactive species, resulting in film growth. The composition of the film reflects that of the adsorbed molecular layer, which at cryogenic temperatures can sensitively be controlled by the partial pressure of the reactant gases. We present results of detailed studies of adsorption, thermal and electron-beam-induced dissociation of disilane and ammonia on silicon. We show that by proper choice of temperature, gas phase composition and electron beam, amorphous silicon, silicon nitride, oxide, silicon oxinitride films can be grown with nearly monolayer thickness resolution.
Maskless Formation of Tungsten Films by Ion Beam Assisted Deposition Technique
Authors: Xu Zheng , Kosugi Toshihiko , Gamo Kenji , Namba Susumu 
Published: March 2011

ABSTRACTW films were deposited on n-GaAs by ion beam assisted deposition technique using low energy H2+ and Ar+, and film properties and residual damage in the substrate were investigated by measuring X-ray photoemission, current-voltage characteristics and deep level transient spectroscopy. Films with a resistivity of 1O−5 ohm·cm were formed. It was observed that damage can be reduced using the low energy beams and that Schottky contacts with n-factor of almost 1 and barrier height of 0.88 eV were formed.
Selective Chemical Vapor Deposition of Tungsten Films on Titanium—Ion—Irradiated Silicon Dioxide
Authors: Okuhira H. , Nishimatsu S. , Ninomiya K. 
Published: March 2011

ABSTRACTSelective area depositon of adherent tungsten (W) film on titanium (Ti)—ion—irradiated silicon dioxide (SiOz) is achieved. First, Ti—ion irradiation through a stencil mask is performed at 600 eV for 1.1 X 1016 atoms/cm2 in a reaction chamber. Next, ArF excimer laser (λ = 193 nm) chemical vapor deposition (CVD) with tungsten hexafluoride (WFs) and hydrogen (H2) is carried out for 40 seconds at 400 K. Finally, low—pressure (LP) CVD is carried out at 600 K and then W films are deposited selectively on the ion—irradiated SiO2 Without the laser CVD step, the ion—irradiation pattern disappears during LPCVD and no W film deposition occurs. Therefore, laser CVD is essential in our experiments.
Laser Processed Silicides for GaAs Hemts
Authors: Anderson W.T. , Christou A. , Thompson P.E. , Davis J.L. , Gossett C.R. , Eridon J.M. , Michelakis C. , Kiriakidis G. , Hatzopoulos Z. , Ethimiopoulos T. , Kudumas D M. , Morgan D.V. 
Published: March 2011

ABSTRACTLaser annealed refractory metal gates and Ohmic contacts have been developed for GaAs FETs and HEMTs fabricated on MBE layers grown on laser desorbed substrates. Amorphous refractory metal silicide films were sputter deposited by a method in which the RF power to separate refractory metal and silicon targets were set at predetermined deposition ratesand the substrates were rotated with respect to the sputter targets receiving a 0.2 to 0.5 nm film on each pass. The gate resistance was reduced and Ohmic contacts formed by pulsed excimer laser annealing.
Novel Photoimaging Schemes at Polymer Surfaces: Their Role in High Resolution Lithography
Authors: Taylor Gary N. , Nalamasu Omkaram , Hutton Richard S. 
Published: March 2011

ABSTRACTPolymer surfaces play essential roles in many technical arenas, but their importance in imaging science and technology has only recently been established. As optical lithography for integrated circuit applications pushes below 0.5μm feature sizes, ever shorter wavelengths and lenses with larger numerical aperatures are required. These narrow the depth-of-focus to such a degree that it eventually becomes less than the substrate topography, resist film thickness and wafer nonuniformity contributions to focus placement. Thick single-layer, surface-conforming resists will not be able to record the aerial image accurately.Surface imaging of planarized single-layer or bilayer organic films offers a means for minimizing the depth-of-focus constraints. This paper outlines this general concept which includes radiation-induced chemical changes in the surface and near-surface regions, amplification of these events by gas-solid reactions with inorganic and organometallic agents and plasma development using an oxygen plasma. Two approaches to surface imaging are discussed. The first employs Plasmask® resist, a very absorbing diazonaphthoquinone-functionalized novolac resin which is exposed and functionalized in the topmost several hundred nm of film. According to Coopmans, Roland and coworkers [14] and Pierrat, et al., [22] two tones are possible depending upon the processing. The present study reports results obtained for both processing modes using 248.4 nm lithography.The second approach involves imaging at the surface and utilizes one of the oldest polymer photoreactions, photo-oxidation, in the imaging step. Hydrophobic aromatic polymers are first irradiated in air to give hydrophilic groups. These sorb water selectively on the hydrophilic areas. The water is reacted in a separate step with an inorganic or organometallic compound such as TiC14 to give a metal oxide film (TiO2) on the exposed areas. Development with an oxygen plasma gives negative tone patterns because TiO2 reduces the etching rate by a factor of ∼ 500 in the exposed regions. Imaging is dependent upon the polymer structure, among other things, and is optimized at shorter wavelengths likely to be used in future exposure systems. From the present results we feel that surface imaging resists may realize 0.25 μm resolution at 193 nm and that <0.10 μm resolution may be achieved using x-ray radiation.
Control of Etching in Laser—Chemical Reaction of Mn—Zn Ferrite by MeV Ion Implantation
Authors: Takai Y. F. LU. M. , Sanda H. , Chayahara A. , Satou M. , Minamisono T. , Namba S. 
Published: March 2011

ABSTRACTThe change in the behavior of laser—induced etching of Mn—Zn ferrite by MeV ion implantation has been investigated. The etching induced by Ar+ laser irradiation in a H3PO4 solutipn w~s completely suppressed by implanting 3 MeV Au+ to a dose of 1x1016 cm-2 when the laser induced local temperature rise was below the melting point of the ferrite. The etching suppression disappeared when the Au+ implanted sample was thermally annealed at 900 ºC for 30 min. The suppression is found to be related to the crystallinity change induced by ion implantation.
Selective Etching and Photo—Bleaching in Thin Amorphous Ge—Sb—S Films
Authors: Savova Evdokia B. , Pashmakoff B.I. 
Published: March 2011

ABSTRACTA mechanism is proposed for the selective etching effects in thin amorphous Ge—Sb—S films based on the combined action of photostructural changes and alkaline solvent with a surface active substance. Evidence is given in support of the assertion thatthe same photostructural changes (namely, the breaking of Ge—Sb bonds under the action of UV light) are responsible for the irreversible photo—bleaching of these layers. Four different compositions in the system Ge—Sb—S have been studied under different preparation conditions (thermal evaporation and laser—beam sputtering).Photostructural changes were induced by UV light irradiation. Infrared spectra of the layers are presented in support of the proposed model.