jap banner
  • Volume/Page
  • Keyword
  • DOI
  • Citation
  • Advanced
   
 
 
 

Flickr Twitter iResearch App Facebook

BROWSE VOLUMES

Year Range: 
Search Issue | RSS Feeds RSS
Previous Issue Next Issue

15 Feb 2004

Volume 95, Issue 4, pp. 1619-2196

Return to All Sections
back to top
RSS Feeds

X-ray characterization of Si microstructures with high spatial resolution

A. Cedola, S. Lagomarsino, F. Scarinci, M. Servidori, and V. Stanic

J. Appl. Phys. 95, 1662 (2004); http://dx.doi.org/10.1063/1.1635652 (5 pages) | Cited 2 times

Online Publication Date: 30 January 2004

Full Text: Read Online (HTML) | Download PDF

Show Abstract
With the advent of the nanolithographic technologies, the demand of a local strain/stress analysis with submicrometer resolution is increasing. In particular, the aim of this work was the study of a patterned Si wafer subjected to preliminary process flow for 0.15 μm complementary metal oxide semiconductor generation. The main purpose was to follow the production of strain induced in the Si substrate during the shallow trench isolation process and subsequent formation of active stripes. The determination of structural parameters with very high spatial resolution in one dimension (300 nm) has been obtained using a scanning x-ray microscope whose main element is a waveguide for medium and high energy x-rays (8–30 keV). The experiment, which takes advantage of a nondispersive geometry, required neither a two-dimensional highly sensitive detector nor an insertion device beamline, but it has been carried out on bending magnet beamlines with relatively low flux. © 2004 American Institute of Physics.
Show PACS
85.40.Ls Metallization, contacts, interconnects; device isolation
85.40.Hp Lithography, masks and pattern transfer
81.16.Nd Micro- and nanolithography
68.37.Yz X-ray microscopy
81.05.Cy Elemental semiconductors
68.47.Fg Semiconductor surfaces
68.60.Bs Mechanical and acoustical properties

Young’s modulus of silicon nitride used in scanning force microscope cantilevers

A. Khan, J. Philip, and P. Hess

J. Appl. Phys. 95, 1667 (2004); http://dx.doi.org/10.1063/1.1638886 (6 pages) | Cited 26 times

Online Publication Date: 30 January 2004

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The Young’s modulus and Poisson’s ratio of high-quality silicon nitride films with 800 nm thickness, grown on silicon substrates by low-pressure chemical vapor deposition, were determined by measuring the dispersion of laser-induced surface acoustic waves. The Young’s modulus was also measured by mechanical tuning of commercially available silicon nitride cantilevers, manufactured from the same material, using the tapping mode of a scanning force microscope. For this experiment, an expression for the oscillation frequencies of two-media beam systems is derived. Both methods yield a Young’s modulus of 280–290 GPa for amorphous silicon nitride, which is substantially higher than previously reported (E=146 GPa). For Poisson’s ratio, a value of ν=0.20 was obtained. These values are relevant for the determination of the spring constant of the cantilever and the effective tip–sample stiffness. © 2004 American Institute of Physics.
Show PACS
07.79.Lh Atomic force microscopes
68.60.Bs Mechanical and acoustical properties

Optical propagation loss of ZnO films grown on sapphire

A. Ashida, H. Ohta, T. Nagata, Y. Nakano, N. Fujimura, and T. Ito

J. Appl. Phys. 95, 1673 (2004); http://dx.doi.org/10.1063/1.1639143 (4 pages) | Cited 4 times

Online Publication Date: 30 January 2004

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Optical propagation losses from ZnO thin films grown on c-cut sapphire were measured for 632.8 nm light using prism coupling and a charge coupled device detection method. Propagation losses varied according to growth temperature and growth rate. No relationship between the distribution of crystallographic orientation and propagation losses was observed. However, propagation losses were found to be insensitive to changes in the distribution of grain orientations. Neither the depth of surface roughness nor the mean interval of the surface undulations was found to be a dominant factor contributing to the losses. A mean angle of surface roughness, α, is proposed as a parameter to comprehensively characterize both effects. Loss is found to depend on α for propagation of both TE0 and TE1 modes. This demonstrates that the parameter α effectively characterizes surface morphology for optical device applications. © 2004 American Institute of Physics.
Show PACS
78.66.Hf II-VI semiconductors
42.82.-m Integrated optics

Simultaneous surface acoustic wave and surface plasmon resonance measurements: Electrodeposition and biological interactions monitoring

J.-M Friedt, L. Francis, G. Reekmans, R. De Palma, A. Campitelli, and U. B. Sleytr

J. Appl. Phys. 95, 1677 (2004); http://dx.doi.org/10.1063/1.1625420 (4 pages) | Cited 3 times

Online Publication Date: 30 January 2004

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We present results from an instrument combining surface acoustic wave propagation and surface plasmon resonance measurements. The objective is to use two independent methods, the former based on adsorbed mass change measurements and the latter on surface dielectric properties variations, to identify physical properties of protein layers, and more specifically their water content. We display mass sensitivity calibration curves using electrodeposition of copper leading to a sensitivity in liquid of 150±15 cm2/g for the Love mode device used here, and the application to monitoring biological processes. The extraction of protein layer thickness and protein to water content ratio is also presented for S-layer proteins under investigation. We obtain, respectively, 4.7±0.7 nm and 75±15%. © 2004 American Institute of Physics.
Show PACS
87.80.-y Biophysical techniques (research methods)
68.35.Iv Acoustical properties
73.20.Mf Collective excitations (including excitons, polarons, plasmons and other charge-density excitations)

Investigation of the multiphoton excitation process of the 4f 25d configuration in LiYF4 and LiLuF4 crystals doped with trivalent neodymium ion

A. F. H. Librantz, L. Gomes, L. V. G. Tarelho, and I. M. Ranieri

J. Appl. Phys. 95, 1681 (2004); http://dx.doi.org/10.1063/1.1640456 (11 pages) | Cited 8 times

Online Publication Date: 30 January 2004

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Ultraviolet (UV) fluorescence of Nd3+ ions induced by multistep laser excitation was investigated in Nd-doped LiYF4 and LiLuF4 crystals using a technique of time-resolved spectroscopy. The observed UV luminescence was due to transitions between the bottom of 4f25d configuration and the 4f3 states of Nd3+ ions. The first absorption band of 4f25d configuration, which starts around 56 700 cm−1, was excited by three stepwise absorptions of photons in the green (500–535 nm) from a short pulse laser excitation leading to broad emission bands in UV range (180–280 nm). An excitation band in the blue (468–486 nm) was observed due to the excitation of the second absorption band of 4f25d configuration around 63 000 cm−1 according to the photon absorption sequence: 4I9/2+hν(480 nm)→2G(1)9/2+hν(480 nm)→2F(2)7/2+hν(480 nm)→4f25d(second). The observed UV emissions (180–280 nm) from the bottom of the 4f25d configuration (first state) have a lifetime of 35 ns (parity allowed) and are broadband in contrast to UV emissions from 4f3 configuration, which are also present in the luminescence investigation but having a longer lifetime (8.5 μs) and structures composed of narrow lines. The excitation spectrum of fast UV luminescence exhibited different structures depending on the excitation geometry (σ or π) with respect to the c axis of the crystal. We observed two emissions from the first state of 4f25d configuration with peaks at 535 and 595 nm modifying the luminescence branching ratio of the bottom of the 4f25d configuration around 55 500 cm−1. The equivalent cross section of three and two excitation processes was estimated at 510 nm by solving the rate equations of the system under short laser excitation, which shows that is possible to have laser action under pulsed laser pumping with intensity below the crystal damage threshold. © 2004 American Institute of Physics.
Show PACS
42.70.Hj Laser materials
78.55.Hx Other solid inorganic materials

Dependence of the stress–temperature coefficient on dislocation density in epitaxial GaN grown on α-Al2O3 and 6H–SiC substrates

I. Ahmad, M. Holtz, N. N. Faleev, and H. Temkin

J. Appl. Phys. 95, 1692 (2004); http://dx.doi.org/10.1063/1.1637707 (6 pages) | Cited 23 times

Online Publication Date: 30 January 2004

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We report measurements of stress in GaN epitaxial layers grown on 6H–SiC and α-Al2O3 substrates. Biaxial stresses span +1.0 GPa (tensile) to −1.2 GPa (compressive). Stress determined from curvature measurements, obtained using phase-shift interferometry (PSI) microscopy, compare well with measurements using accepted techniques of x-ray diffraction (XRD) and Raman spectroscopy. Correlation between XRD and Raman measurements of the E22 phonon gives a Raman-stress factor of −3.4±0.3 cm−1/GPa. We apply PSI microscopy for temperature dependent stress measurements of the GaN films. Variations found in the stress–temperature coefficient correlate well with threading dislocation densities. We develop a phenomenological model which describes the thermal stress of the epitaxial GaN as a superposition of that for ideal GaN and the free volume existing in the layers due to the threading dislocations. The model describes well the observed dependence. © 2004 American Institute of Physics.
Show PACS
68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.
61.72.Lk Linear defects: dislocations, disclinations

Molecular dynamics simulations of the effects of defects on martensite nucleation

B. Li, X. M. Zhang, P. C. Clapp, and J. A. Rifkin

J. Appl. Phys. 95, 1698 (2004); http://dx.doi.org/10.1063/1.1638609 (8 pages) | Cited 11 times

Online Publication Date: 30 January 2004

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The effects of various lattice defects, such as a single edge dislocation, dislocation configurations, a low-angle grain boundary, and a high-angle grain boundary, on martensite nucleation and growth were investigated by performing molecular dynamics simulations, using EAM interatomic potentials for Ni–Al alloy. Stress induced and thermally activated martensitic transformations were studied in the cases that various defects were introduced into the simulated system. The simulation results show that the nucleation patterns were closely related to the stresses of the dislocation configurations, in the sense that the locations where stresses assist the lattice distortion of the transformation are favorable for martensite nucleation. A symmetric, tilt low-angle grain boundary is not favorable for martensite nucleation, because the stresses of the constituent dislocations cancel one another and stresses that assist the lattice distortion cannot be produced. The low-angle boundary hinders the martensite growth due to the high stability of this type of dislocation configuration. A relaxed, high-angle grain boundary (coincident site lattice) is also not favorable for martensite nucleation, because of the lack of long-range stress field. © 2004 American Institute of Physics.
Show PACS
81.30.Kf Martensitic transformations
61.72.Bb Theories and models of crystal defects

Application of real-time, stroboscopic x-ray diffraction with dynamical mechanical analysis to characterize the motion of ferroelastic domain walls

Richard J. Harrison, Simon A. T. Redfern, Andrew Buckley, and Ekhard K. H. Salje

J. Appl. Phys. 95, 1706 (2004); http://dx.doi.org/10.1063/1.1639949 (12 pages) | Cited 46 times

Online Publication Date: 30 January 2004

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The dynamic response of ferroelastic twins to an alternating stress has been studied in situ at high temperature using a stroboscopic x-ray diffractometer and combined dynamical mechanical analyzer (XRD-DMA). The XRD-DMA is designed to allow x-ray rocking curves to be collected while the sample is undergoing simultaneous dynamical mechanical analysis in three-point-bend geometry. The detection of diffracted x-rays is synchronized with the applied load, so that rocking curves corresponding to different parts of the dynamic load cycle can be obtained separately. The technique is applied to single-crystal LaAlO3, which undergoes a cubic to rhombohedral phase transition at 550 °C, leading to the generation of characteristic “chevron” twins. The rocking-curve topology is calculated as a function of crystal orientation for each chevron type. Systematic changes in the rocking curves during heating and cooling under dynamic load demonstrate a clear preference for chevrons containing {100}pc walls perpendicular to the sample surface and {110}pc walls oriented at 45° to the sample surface. These domain walls are oriented favorably with respect to the applied stress (i.e., they separate domains with contrasting components of spontaneous strain parallel to the sample length). Below 200 °C, the superelastic strain is accommodated by rapid advancement/retraction of vertical {100}pc needle domains, with little effect on the dynamic rocking curves. Above 200 °C, a dynamic shift in peak position between rocking curves measured at the maximum and minimum applied loads is detected. The onset of a dynamic response correlates with the loss of the {100}pc needle domains and the transformation of the microstructure to 45° {110}pc walls. Superelastic strain is then accommodated by domain wall displacement/rotation, causing the wall to sweep back and forth across the x-ray beam and diffraction to occur from alternate domains at the maximum and minimum points of the stress cycle. A second sample, oriented so that domain walls in all possible chevrons are unfavorably oriented with respect to the applied stress, shows very different behavior. The rocking curves consist of several well-separated peaks at the minimum load and a single broad diffraction signal at the maximum load. This is caused by the creation of a very high density of twin walls across the sample above a critical applied stress, leading to corrugation of the sample surface. © 2004 American Institute of Physics.
Show PACS
75.60.Ch Domain walls and domain structure
07.85.Jy Diffractometers

Fundamental structure of steady plastic shock waves in metals

A. Molinari and G. Ravichandran

J. Appl. Phys. 95, 1718 (2004); http://dx.doi.org/10.1063/1.1640452 (15 pages) | Cited 13 times

Online Publication Date: 30 January 2004

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The propagation of steady plane shock waves in metallic materials is considered. Following the constitutive framework adopted by R. J. Clifton [Shock Waves and the Mechanical Properties of Solids, edited by J. J. Burke and V. Weiss (Syracuse University Press, Syracuse, N.Y., 1971), p. 73] for analyzing elastic–plastic transient waves, an analytical solution of the steady state propagation of plastic shocks is proposed. The problem is formulated in a Lagrangian setting appropriate for large deformations. The material response is characterized by a quasistatic tensile (compression) test (providing the isothermal strain hardening law). In addition the elastic response is determined up to second order elastic constants by ultrasonic measurements. Based on this simple information, it is shown that the shock kinetics can be quite well described for moderate shocks in aluminum with stress amplitude up to 10 GPa. Under the later assumption, the elastic response is assumed to be isentropic, and thermomechanical coupling is neglected. The model material considered here is aluminum, but the analysis is general and can be applied to any viscoplastic material subjected to moderate amplitude shocks. Comparisons with experimental data are made for the shock velocity, the particle velocity and the shock structure. The shock structure is obtained by quadrature of a first order differential equation, which provides analytical results under certain simplifying assumptions. The effects of material parameters and loading conditions on the shock kinetics and shock structure are discussed. The shock width is characterized by assuming an overstress formulation for the viscoplastic response. The effects on the shock structure of strain rate sensitivity are analyzed and the rationale for the J. W. Swegle and D. E. Grady [J. Appl. Phys. 58, 692 (1985)] universal scaling law for homogeneous materials is explored. Finally, the ability to deduce information on the viscoplastic response of materials subjected to very high strain rates from shock wave experiments is discussed. © 2004 American Institute of Physics.
Show PACS
62.50.-p High-pressure effects in solids and liquids
81.05.Bx Metals, semimetals, and alloys

Approach for reducing the Rayleigh scattering loss in optical fibers

K. Saito, M. Yamaguchi, A. J. Ikushima, K. Ohsono, and Y. Kurosawa

J. Appl. Phys. 95, 1733 (2004); http://dx.doi.org/10.1063/1.1638887 (3 pages) | Cited 4 times

Online Publication Date: 30 January 2004

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Structural relaxations in fiber cores and claddings with various F concentrations were investigated. It was found that structural relaxation in the core is strongly affected by that in the cladding. This effect leads to an approach to control structural relaxation in fiber core for reducing the Rayleigh scattering loss in optical fibers. The advantage of this approach is to avoid increase of the Rayleigh scattering due to concentration fluctuation. © 2004 American Institute of Physics.
Show PACS
42.81.Dp Propagation, scattering, and losses; solitons
78.35.+c Brillouin and Rayleigh scattering; other light scattering

Lateral short range ordering of step bunches in InGaAs/GaAs superlattices

M. Hanke, M. Schmidbauer, R. Köhler, H. Kirmse, and M. Pristovsek

J. Appl. Phys. 95, 1736 (2004); http://dx.doi.org/10.1063/1.1640786 (4 pages) | Cited 2 times

Online Publication Date: 30 January 2004

Full Text: Read Online (HTML) | Download PDF

Show Abstract
In the present paper we report on structural investigations of fivefold In0.2Ga0.8As/GaAs superlattices which have been grown by means of metal organic chemical vapor deposition on vicinal GaAs(001) substrates. Cross-sectional transmission electron micrographs exhibit an initially flat and nonfaceted grooved surface, while step bunching occurs during subsequent growth stages with an inclined vertical inheritance approximately 45° off the (001) direction. A reconstructed sample cross section on the base of high resolution x-ray diffraction data qualitatively confirms the local morphology proved by transmission electron microscopy. Moreover, a line shape analysis of diffusely scattered intensity using Gauss profiles indicates a lateral short range ordering of step bunches. © 2004 American Institute of Physics.
Show PACS
68.65.Cd Superlattices
68.55.-a Thin film structure and morphology
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)

Influence of three-dimensional transition elements on magnetic and structural phase transitions of Ni-Mn-Ga alloys

A. A. Cherechukin, T. Takagi, H. Miki, M. Matsumoto, and M. Ohtsuka

J. Appl. Phys. 95, 1740 (2004); http://dx.doi.org/10.1063/1.1641184 (3 pages) | Cited 9 times

Online Publication Date: 30 January 2004

Full Text: Read Online (HTML) | Download PDF


See Also: RETRACTION

Show Abstract
Differential scanning calorimetry and magnetic measurements were performed to study the influence of the ferromagnetic three-dimensional transition elements Fe and Co on the structural and magnetic properties of the ferromagnetic shape memory alloys Ni-Mn-Ga. Substitution of Fe or Co for Ni decreases the temperature of martensitic phase transition Tm, whereas substitution of Co for Mn results in a considerable increase of Tm. Magnetic measurement revealed that Curie temperature TC increased upon substitution of Fe or Co for Ni. This may be useful for design of high-temperature ferromagnetic shape memory alloys. © 2004 American Institute of Physics.
Show PACS
75.30.Kz Magnetic phase boundaries (including classical and quantum magnetic transitions, metamagnetism, etc.)
64.70.K- Solid-solid transitions
81.30.Kf Martensitic transformations
75.40.Cx Static properties (order parameter, static susceptibility, heat capacities, critical exponents, etc.)

Effect of polishing stress on Raman spectra of the Mn–Zn ferrite

Osamu Yamashita and Teruki Ikeda

J. Appl. Phys. 95, 1743 (2004); http://dx.doi.org/10.1063/1.1641522 (6 pages) | Cited 4 times

Online Publication Date: 30 January 2004

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Raman scattering measurements were made on polycrystalline Mn0.62Zn0.30Fe2.08O4 ferrites with various degrees of stress generated during the polishing process, in the temperature range from 175 to 603 K. Raman spectra were found at energies of 337, 464, and 620 cm−1 in substrates with low stress. The integral intensities at 337 and 620 cm−1 increased significantly with decreasing residual stress stored in the surface. The former integral intensity remained constant with increasing temperature and decreased in the vicinity of the Néel point, while the latter one decreased linearly with increasing temperature through the Néel point. However, their linewidths changed little with stress and temperature, unlike the case of GaAs. These two spectra of the Mn–Zn ferrite, therefore, are considered to arise predominantly from the spin-dependent phonon scattering, in addition to the usual optical phonon scattering. It was thus found that the Raman intensity associated closely with the magnetic ordering is highly sensitive to the residual stress in the crystal, as in the case of the optical phonon, and Raman spectroscopy is also applicable to the evaluation of the stress in soft magnetic ferrites. © 2004 American Institute of Physics.
Show PACS
81.65.Ps Polishing, grinding, surface finishing
75.50.Gg Ferrimagnetics
78.30.Hv Other nonmetallic inorganics
75.40.-s Critical-point effects, specific heats, short-range order
78.66.Nk Insulators

Barrier-limited surface diffusion in atom lithography

E. te Sligte, K. M. R. van der Stam, B. Smeets, P. van der Straten, R. E. Scholten, H. C. W. Beijerinck, and K. A. H. van Leeuwen

J. Appl. Phys. 95, 1749 (2004); http://dx.doi.org/10.1063/1.1638613 (7 pages) | Cited 6 times

Online Publication Date: 30 January 2004

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Thermally activated surface diffusion has a strong influence on structure widths in atom lithography. We investigate the effects of two barriers to thermally activated atomic diffusion on atom lithography: a thermally activated Ehrlich–Schwoebel (ES) barrier, and pollution from the residual gas in the vacuum system. We performed kinetic Monte Carlo simulations using a one-dimensional surface grid. We find that the ES barrier fails to explain the lack of temperature dependence observed experimentally [W. R. Anderson et al., Phys. Rev. A 59, 2476 (1999)]. The dependencies of the structure width on temperature, vacuum conditions, and beam characteristics can be explained using the pollutant adatom hypothesis. Only the variation of structure width with deposition duration was not entirely reproduced by this model. We attribute this to the one-dimensional nature of our simulations. These results demonstrate that barrier-limited diffusion can play an important role in atom lithography, and that pollutant adatoms are a likely candidate barrier. © 2004 American Institute of Physics.
Show PACS
85.40.Hp Lithography, masks and pattern transfer
68.35.Fx Diffusion; interface formation

Dependence on liquid temperature and purity of light emission characteristics in single cavitation bubble luminescence

Mario O. Barbaglia and Fabián J. Bonetto

J. Appl. Phys. 95, 1756 (2004); http://dx.doi.org/10.1063/1.1637711 (4 pages) | Cited 4 times

Online Publication Date: 30 January 2004

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We produced single bubbles in water using a visible pulsed laser and studied the characteristics of the light emitted during the bubble collapse time as a function of the water temperature for different water purity values. The water temperature ranged from freezing point (0 °C) to near boiling. We measured the luminescence pulse for the mentioned temperature range at various purity values. We also obtained the average bubble lifetime and the average luminescence pulse emitted as a function of water temperature. The main conclusion was that the luminescence can be modified by the water quality and by the water temperature. Maximum luminescence was obtained near the water freezing point. © 2004 American Institute of Physics.
Show PACS
47.55.D- Drops and bubbles
47.55.dp Cavitation and boiling
61.80.Ba Ultraviolet, visible, and infrared radiation effects (including laser radiation)
78.55.Bq Liquids

Shock-wave compression of a porous material

A. D. Resnyansky and N. K. Bourne

J. Appl. Phys. 95, 1760 (2004); http://dx.doi.org/10.1063/1.1640460 (10 pages) | Cited 16 times

Online Publication Date: 30 January 2004

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Porous materials may exhibit highly nonstationary behavior under shock-wave loading. The majority of existing experiments have measured the dependence between shock-wave velocity and particle velocity to define the Hugoniot for subsequent derivation of an equation of state. Such equations of state are nonconvex, which leads to significant thermodynamic and numerical problems. The present article suggests an experimental configuration and mathematical model, to overcome these difficulties. The experiment is based on a setup resulting in a continuous record of the stress profile with time using embedded manganin gauges. The model employs a homogenization approach enabling us to obtain a hyperbolic system of equations, which is completed with a convex equation of state so as to be suitable for implementation in commercial hydrocodes. Using available data for porous aluminum, an approach is elaborated for construction of constitutive equations. The model is tested with the present stress profiles in sand and demonstrates good agreement. © 2004 American Institute of Physics.
Show PACS
62.50.-p High-pressure effects in solids and liquids
64.10.+h General theory of equations of state and phase equilibria

Thermal growth of silicon oxynitride films on Si: A reaction-diffusion approach

R. M. C. de Almeida, I. J. R. Baumvol, J. J. Ganem, I. Trimaille, and S. Rigo

J. Appl. Phys. 95, 1770 (2004); http://dx.doi.org/10.1063/1.1639139 (4 pages) | Cited 1 time

Online Publication Date: 30 January 2004

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We present some experimental results and propose a reaction-diffusion model to describe thermal growth of silicon oxynitride films on Si in NO and N2O, as well as annealing in NO of thermally grown silicon oxide films on Si. We obtain growth kinetics and N and O depth distributions for the different growth routes by changing only initial and boundary conditions of a set of nonlinear differential equations. The results suggest that the puzzling differences in film growth rate and N incorporation originate from dynamical effects, rather than in differences in chemical reactions. © 2004 American Institute of Physics.
Show PACS
68.55.A- Nucleation and growth
81.15.Aa Theory and models of film growth
81.65.Mq Oxidation

Site-selective study of Nd3+ optical centers in Ca3Sc2Ge3O12 laser garnet crystals

J. J. Romero, D. Jaque, L. E. Bausá, and E. Cavalli

J. Appl. Phys. 95, 1774 (2004); http://dx.doi.org/10.1063/1.1641952 (6 pages) | Cited 4 times

Online Publication Date: 30 January 2004

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The Nd3+ multicenter distribution in a Ca3Sc2Ge3O12 garnet laser crystal has been analyzed by low temperature site-selective laser spectroscopy. Two nonequivalent Nd3+ centers have been identified and characterized in this host lattice. The effect of codoping the crystal with MgO on the Nd3+ center distribution has also been investigated, since this codoping enables considerable enhancement of the doping levels of these crystals. Three different centers were observed in the codoped crystals, together with a reduction of inhomogeneous emission broadening. The nature of the optical centers present in both cases is discussed by considering the charge compensation mechanisms involved in accommodation of Nd3+ ions. © 2004 American Institute of Physics.
Show PACS
75.50.Gg Ferrimagnetics
61.72.S- Impurities in crystals
78.66.Nk Insulators

Mechanical and thermal stresses in multilayered materials

Jürgen Malzbender

J. Appl. Phys. 95, 1780 (2004); http://dx.doi.org/10.1063/1.1642289 (3 pages) | Cited 18 times

Online Publication Date: 30 January 2004

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A general solution for elastic deformation of monolithic and multilayered materials due to external loads and moments, mismatch in thermal expansion, and temperature gradients is derived. Special consideration is given to materials with stress dependent stiffness or gradient in elastic modulus. The relationships can be used to determine the stiffness, thickness, thermal expansion coefficient, or thermal gradient. The fracture of a monolithic material with stress dependent stiffness and the temperature dependence of the elastic modulus and thickness are considered as well as the possibility to use the change in curvature in the case of delamination to determine the fracture energy. © 2004 American Institute of Physics.
Show PACS
68.65.Ac Multilayers
81.40.Jj Elasticity and anelasticity, stress-strain relations
62.20.D- Elasticity
62.20.F- Deformation and plasticity
81.40.Np Fatigue, corrosion fatigue, embrittlement, cracking, fracture, and failure
62.20.M- Structural failure of materials
65.40.De Thermal expansion; thermomechanical effects
68.35.Gy Mechanical properties; surface strains

Modification of the optical properties of Ag-implanted silica by annealing in two different atmospheres

J. Roiz, A. Oliver, E. Muñoz, L. Rodríguez-Fernández, J. M. Hernández, and J. C. Cheang-Wong

J. Appl. Phys. 95, 1783 (2004); http://dx.doi.org/10.1063/1.1635653 (9 pages) | Cited 19 times

Online Publication Date: 30 January 2004

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Significant changes in the optical properties of nanometer-size Ag clusters embedded in high-purity silica were obtained. Samples were prepared by 2 MeV Ag-ion implantation with fluences in the 2.8–3.8×1016 ions/cm2 range and subsequent annealing at various temperatures in air (oxidizing atmosphere) or in a hydrogen-rich atmosphere (reducing atmosphere). Changes consisted of large and small blueshifts of the resonance surface plasmon peak position, light absorption modification in the ultraviolet (UV) region, increased optical extinction in all the spectrum wavelength range, and different resonance peak height depending on annealing atmosphere. Optical property changes were analyzed in terms of Ag cluster size, interaction at cluster–matrix interface, cluster hydrogen content, diffusivity and conductivity. Bands in the UV region are reported. © 2004 American Institute of Physics.
Show PACS
78.67.Bf Nanocrystals, nanoparticles, and nanoclusters
78.20.Ci Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity)
78.40.Kc Metals, semimetals, and alloys
61.46.-w Structure of nanoscale materials
61.72.Cc Kinetics of defect formation and annealing
61.72.up Other materials
61.72.S- Impurities in crystals
73.20.Mf Collective excitations (including excitons, polarons, plasmons and other charge-density excitations)

Growth and characterization of hydrogenated amorphous silicon thin films from SiH2 radical precursor: Atomic-scale analysis

Saravanapriyan Sriraman, Eray S. Aydil, and Dimitrios Maroudas

J. Appl. Phys. 95, 1792 (2004); http://dx.doi.org/10.1063/1.1636512 (14 pages) | Cited 7 times

Online Publication Date: 30 January 2004

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Molecular-dynamics (MD) simulations of hydrogenated amorphous silicon (a-Si:H) film growth on an initially H-terminated Si(001)-(2×1) substrate at T=500 K was studied through repeated impingement of SiH2 radicals to elucidate the effects of this species on the structural quality of the deposited films. A detailed analysis of the radical–surface interaction trajectories revealed the important reactions contributing to film growth. These reactions include (i) adsorption of SiH2 onto the deposition surface, (ii) insertion of SiH2 into surface SiSi bonds, (iii) surface dimerization of adsorbed SiH2 groups, (iv) formation of polysilane chains and islands, (SiH2)n, n⩾2, on the surface, (v) formation of higher surface hydrides through the exchange of hydrogen, and (vi) dangling-bond-mediated dissociation of surface hydrides. The MD simulations of a-Si:H film growth predict an overall surface reaction probability of 39% for the SiH2 radical. Structural and chemical characterization of the deposited films was carried out through a detailed analysis of the evolution of the structure of the film, surface morphology, and roughness, surface reactivity, and surface composition. The analysis revealed that the deposited films exhibit a high concentration of H and columnar surface morphologies. In particular, islands or polysilane chains form on the growth surface and are believed to be responsible for the columnar structural features in the deposited film. Such polysilane chain formation may have significant effects on the structural, morphological, and optical properties of the a-Si:H films. © 2004 American Institute of Physics.
Show PACS
68.55.-a Thin film structure and morphology
61.43.Dq Amorphous semiconductors, metals, and alloys
68.55.A- Nucleation and growth
61.43.Bn Structural modeling: serial-addition models, computer simulation
81.05.Gc Amorphous semiconductors
79.20.Rf Atomic, molecular, and ion beam impact and interactions with surfaces
68.35.Dv Composition, segregation; defects and impurities
68.43.Bc Ab initio calculations of adsorbate structure and reactions
52.77.Dq Plasma-based ion implantation and deposition
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)

High pressure ultrasonic and x-ray studies on monolithic SiC composite

George M. Amulele, Murli H. Manghnani, Baosheng Li, Daniel J. H. Errandonea, Maddury Somayazulu, and Yue Meng

J. Appl. Phys. 95, 1806 (2004); http://dx.doi.org/10.1063/1.1639141 (5 pages) | Cited 8 times

Online Publication Date: 30 January 2004

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The equation of state (pressure-volume relationship) of a monolithic SiC composite has been determined separately by high pressure ultrasonic and x-ray techniques. The ultrasonic measurements were performed on a cylindrical specimen, 2.2 mm in diameter and 2.2 mm in length, in a large-volume uniaxial split cylinder press to 13.6 GPa. The synchrotron measurements were carried out on the polycrystalline sample loaded in a diamond anvil cell up to a pressure of 27 GPa. The room temperature bulk modulus obtained from the ultrasonic measurements is K0=216.5±1.1 GPa and the pressure derivative is K0′=4.19±0.09. The shear modulus obtained is G0=196.7±0.7 GPa with its pressure derivative G0′=0.95±0.03. Using K0′ obtained from the ultrasonic measurements in the Birch–Murnaghan equation to fit the synchrotron x-ray data, we obtain a bulk modulus of K0=218.4±4.9 GPa for the composite. © 2004 American Institute of Physics.
Show PACS
64.30.-t Equations of state of specific substances
61.05.cp X-ray diffraction
62.80.+f Ultrasonic relaxation

Influence of growth rate on charge transport in GaSb homojunctions prepared by metalorganic vapor phase epitaxy

Dobroslav Kindl, Jana Toušková, Eduard Hulicius, Jiří Pangrác, Tomislav Šimeček, Vlastimil Jurka, Pavel Hubík, Jiří J. Mareš, and Jozef Krištofik

J. Appl. Phys. 95, 1811 (2004); http://dx.doi.org/10.1063/1.1640794 (5 pages) | Cited 3 times

Online Publication Date: 30 January 2004

Full Text: Read Online (HTML) | Download PDF


See Also: Publisher's Note

Show Abstract
Dark current–voltage (I–V) characteristic measurement in the temperature range from −190 °C to 65 °C was carried out on GaSb p-n homojunctions prepared by low-pressure metalorganic vapor phase epitaxy. It was shown that the charge transport mechanism in these homojunctions is strongly affected by the growth rate of GaSb epitaxial layers. Samples prepared at higher growth rate (40 nm/min.) exhibit an anomalous low-temperature peak of tunneling current which can be explained by the presence of a narrow band of energies due to high concentration of native defects, probably GaSb antisites. The same defect levels are responsible for the generation–recombination current which dominates in these samples at higher temperatures. On the other hand, quite different behavior was found in the case of slowly grown (20 nm/min) samples. At sufficiently low temperatures, a current maximum near 50 mV of forward voltage points out a band-to-band tunneling as a prevailing transport mechanism. With increasing temperature, however, this maximum disappears as at least one side of the junction becomes nondegenerate. Combination of the tunneling via energy states in the band gap and the thermal current governs the forward I–V characteristics at higher temperatures, whereas the direct tunneling remains dominant in the reverse direction. © 2004 American Institute of Physics.
Show PACS
73.40.Kp III-V semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions
71.55.Eq III-V semiconductors
73.61.Ey III-V semiconductors
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
81.15.Kk Vapor phase epitaxy; growth from vapor phase
71.20.Nr Semiconductor compounds

Glass-forming ability and crystallization behavior of Ti–Cu–Ni–Sn–M (M=Zr, Mo, and Ta) metallic glasses

G. He, J. Eckert, and M. Hagiwara

J. Appl. Phys. 95, 1816 (2004); http://dx.doi.org/10.1063/1.1643776 (6 pages) | Cited 6 times

Online Publication Date: 30 January 2004

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The kinetics of the glass transition and the crystallization behavior of Ti–Cu–Ni–Sn–M (M=Zr,Mo,Ta) glassy alloys were investigated by differential scanning calorimetry and x-ray diffraction. The glass-forming ability (GFA) of the glasses was analyzed in terms of the fragility concept and the width of the supercooled liquid region. The Ti-base glasses studied were found to have lower GFA than Zr, Pd, La, Fe, Mg-base bulk metallic glasses (BMGs), but to be comparative GFA to Ni- and Au-base BMGs. Higher Mo content or higher Ti–Ta content in the alloys lowers the GFA. The chemical complexity and multiphase crystallization requiring long-range atomic diffusion may contribute to the thermal stability of the supercooled liquid against crystallization. The products of crystallization of the glasses include bcc β-Ti(M) solid solution and Ti2Ni and Ti2Cu intermetallics. © 2004 American Institute of Physics.
Show PACS
81.05.Kf Glasses (including metallic glasses)
64.70.P- Glass transitions of specific systems
64.70.Q- Theory and modeling of the glass transition
81.70.Pg Thermal analysis, differential thermal analysis (DTA), differential thermogravimetric analysis
61.43.Fs Glasses

Analysis of electroluminescence spectra of silicon and gallium arsenide p–n junctions in avalanche breakdown

M. Lahbabi, A. Ahaitouf, M. Fliyou, E. Abarkan, J.-P. Charles, A. Bath, A. Hoffmann, S. E. Kerns, and D. V. Kerns

J. Appl. Phys. 95, 1822 (2004); http://dx.doi.org/10.1063/1.1643188 (7 pages) | Cited 7 times

Online Publication Date: 30 January 2004

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We present a generalized study of light emission from reverse biased p–n junctions under avalanche breakdown conditions. A model is developed based on direct and indirect interband processes including self-absorption to describe measured electroluminescence spectra. This model was used to analyze experimental data for silicon (Si) and gallium arsenide p–n junctions and can be extended to several types of semiconductors regardless of their band gaps. This model can be used as a noninvasive technique for the determination of the junction depth. It has also been used to explain the observed changes of the Si p–n junction electroluminescence spectra after fast neutron irradiation. In particular, it is demonstrated that the neutron irradiation affects both the semiconductor and the overlying passivation oxide layer. © 2004 American Institute of Physics.
Show PACS
78.60.Fi Electroluminescence
61.82.Fk Semiconductors
61.80.Hg Neutron radiation effects
81.65.Rv Passivation
72.20.Ht High-field and nonlinear effects
73.40.Kp III-V semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions
73.40.Lq Other semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions
Return to All Sections
Close

Google Calendar

ADVERTISEMENT

Go to AIP Home   © AIP Publishing LLC
close