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

Flickr Twitter UniPHY Group iResearch App Facebook

SECTION LISTING

BROWSE VOLUMES

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

15 May 2002

Volume 91, Issue 10, pp. 6227-8917

Page 1 of 31 Pages Next Page | Jump to Page
back to top
RSS Feeds

Adhesive bonding in microelectronics and photonics

B. G. Yacobi, S. Martin, K. Davis, A. Hudson, and M. Hubert

J. Appl. Phys. 91, 6227 (2002); http://dx.doi.org/10.1063/1.1467950 (36 pages) | Cited 17 times

Online Publication Date: 13 May 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The use of adhesive bonding in joining of materials with different characteristics is of major importance in a variety of microelectronic and photonic applications. The curing of such adhesives is also of great consequence, with the use of optical radiation for adhesive curing becoming the method of choice in various applications, especially bonding of components in microelectronics and fiber–optic assembly. This article reviews recent advances in the development of adhesives, their applications, and their curing methods using optical radiation; it also includes a brief overview of the adhesion mechanisms. © 2002 American Institute of Physics.
Show PACS
68.35.Np Adhesion
81.90.+c Other topics in materials science (restricted to new topics in section 81)
85.40.-e Microelectronics: LSI, VLSI, ULSI; integrated circuit fabrication technology
01.30.Rr Surveys and tutorial papers; resource letters
42.81.Bm Fabrication, cladding, and splicing
81.20.Vj Joining; welding
back to top
RSS Feeds

Wavelength demodulation using optically quenched lasers

Michael A. Parker

J. Appl. Phys. 91, 6263 (2002); http://dx.doi.org/10.1063/1.1467404 (3 pages) | Cited 1 time

Online Publication Date: 13 May 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Gain quenched lasers can satisfy the requirements for all-optical switches in communications and computing systems. Hitherto, these devices have lacked optical gain between the input beam and output beam, and have been limited to switching amplitude modulated optical signals. A simple model based on the laser rate equations demonstrates that quenched devices can convert wavelength modulated signals into amplitude modulated ones with programmable optical gain. The discussion includes the effect of carrier injection, laser construction, and type of heterostructure. © 2002 American Institute of Physics.
Show PACS
42.60.Fc Modulation, tuning, and mode locking
42.55.Px Semiconductor lasers; laser diodes
42.60.By Design of specific laser systems
42.79.Hp Optical processors, correlators, and modulators
42.79.Sz Optical communication systems, multiplexers, and demultiplexers
84.40.Ua Telecommunications: signal transmission and processing; communication satellites
42.65.Pc Optical bistability, multistability, and switching, including local field effects

Effects of nitrogen on GaAsP light-emitting diodes

Tadashige Sato and Megumi Imai

J. Appl. Phys. 91, 6266 (2002); http://dx.doi.org/10.1063/1.1469664 (7 pages)

Online Publication Date: 13 May 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The effects of nitrogen on GaAsP light-emitting diodes grown by hydride vapor phase epitaxy are described. Nitrogen acts as an isoelectronic trap and this localized state makes GaAsP a widely used material for from-yellow-to-red visible light-emitting diodes. The photoluminescence and electroluminescence spectra, brightness, and reliability were investigated systematically in line with the function of nitrogen concentration, from 0 (without nitrogen) to 2.3×1019 cm−3. When the nitrogen concentration reached 2.3×1019 cm−3, the total emission in the photoluminescence spectrum at 4.2 K showed a redshift. The study provides clarification of the effects of nitrogen on the diodes and demonstrates that the characteristics of the diodes strongly depend on the nitrogen concentration. © 2002 American Institute of Physics.
Show PACS
85.60.Jb Light-emitting devices
78.60.Fi Electroluminescence
78.55.Cr III-V semiconductors
78.66.Fd III-V semiconductors
73.50.Gr Charge carriers: generation, recombination, lifetime, trapping, mean free paths

Nonequilibrium photocurrent modeling in resonant tunneling photodetectors

Lindor E. Henrickson

J. Appl. Phys. 91, 6273 (2002); http://dx.doi.org/10.1063/1.1473677 (9 pages) | Cited 8 times

Online Publication Date: 13 May 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
An efficient and versatile many-body nonequilibrium approach is formulated for computation of photocurrent and photoexcited properties of device structures where quantum effects dominate. This method, based on nonequilibrium Green’s function quantum transport equations, makes it possible to consider open systems of arbitrary dimensionality having complex potentials, complex geometries, and multiple terminals. In contrast to other approximate computational approaches, no a priori assumptions regarding the particular nature of the phototransitions are required (i.e., bound-to-bound, bound-to-continuum, or continuum-to-continuum). Furthermore, if desired, electron–phonon and electron–electron interactions can also be rigorously accounted for within the same formalism. In this article, the method is applied to two typical resonant-tunneling infrared detector heterostructures as examples: (1) a single-quantum-well structure, and (2) a multiperiod superlattice structure. © 2002 American Institute of Physics.
Show PACS
85.60.Gz Photodetectors (including infrared and CCD detectors)
85.35.Ds Quantum interference devices
85.30.Mn Junction breakdown and tunneling devices (including resonance tunneling devices)
73.50.Pz Photoconduction and photovoltaic effects
71.38.-k Polarons and electron-phonon interactions
back to top
RSS Feeds

Time evolution of an ion-ion plasma after the application of a direct current bias voltage

Vikas Midha, Badri Ramamurthi, and Demetre J. Economou

J. Appl. Phys. 91, 6282 (2002); http://dx.doi.org/10.1063/1.1468256 (6 pages) | Cited 4 times

Online Publication Date: 13 May 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A one-dimensional fluid model was developed to investigate the time evolution of a positive ion-negative ion (ion-ion) plasma after the application of a direct current (dc) bias voltage. The ion mass and momentum continuity equations were coupled to the Poisson equation for the electric field. The applied bias is shielded and space charge sheaths are formed within the time scale of ion response (ion plasma frequency). When the ion collision frequency is low compared to the ion plasma frequency, electric field oscillations develop in the bulk due to the ion inertia (overshoot). The net charge density in the sheath, the sheath electric field, and the flux and energy of ions bombarding the electrodes all go through maximum values at a time comparable to the ion plasma frequency. Over long time scales the sheaths are in quasiequilibrium with the bulk plasma. At this time, the ion flux on each electrode is twice the free diffusion flux. © 2002 American Institute of Physics.
Show PACS
52.65.Cc Particle orbit and trajectory
52.40.Kh Plasma sheaths
52.20.-j Elementary processes in plasmas
52.25.-b Plasma properties
52.35.Fp Electrostatic waves and oscillations (e.g., ion-acoustic waves)

Spatially resolved electron temperatures, species concentrations, and electron energy distributions in inductively coupled chlorine plasmas, measured by trace-rare gases optical emission spectroscopy

V. M. Donnelly and M. J. Schabel

J. Appl. Phys. 91, 6288 (2002); http://dx.doi.org/10.1063/1.1467398 (8 pages) | Cited 20 times

Online Publication Date: 13 May 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Determining the spatial dependence of charged and neutral species concentrations and energies in inductively coupled plasmas (ICP) is important for understanding basic plasma chemistry and physics, as well as for optimizing the placement of the wafer with respect to the ICP source to maximize properties such as etching rate uniformity, while minimizing charging-induced damage and feature profile anomalies. We have determined the line-integrated electron temperature (Te) and Cl-atom number density (nCl) as a function of the axial distance (z) from the wafer in a chlorine ICP, using trace rare gases optical emission spectroscopy (TRG-OES). By selecting rare gas lines that are either (a) excited mostly from the ground states, or (b) excited mainly from the metastable states we were also able to obtain approximate electron energy distributions functions (EEDFs). The gap between the wafer and the window adjacent to the flat coil inductive source was fixed at 15 cm. The pressure was 2, 10, or 20 mTorr (95% Cl2, 1% each of He, Ne, Ar, Kr, Xe) and the inductive mode source power was 340 or 900 W. Te measured by TRG-OES, mostly characteristic of the high-energy (>10 eV) part of the EEDF, peaked near the source under all conditions except 2 mTorr and 900 W, where a maximum Te of 5.5 eV was observed at midgap. The falloff in this high-electron-energy Te away from the source is mainly due to a preferential loss of high-energy electrons, which can be explained by an increasingly depleted (with increasing energy) EEDF, combined with the nonlocal effect: electrons lose kinetic energy as they approach the higher potential energy regions of lower electron density near the wafer. At 20 mTorr and 340 W, the mean free path for inelastic scattering by high-energy electrons becomes comparable to the reactor dimensions, causing added cooling of the EEDF near the wafer. TRG-OES EEDFs measured at a distance of 3 cm from the wafer and 900 W are in excellent agreement with previous Langmuir probe measurements. nCl increased with power and was highest at 900 W in the region between midgap and the ICP window, reaching a level corresponding to a high degree of dissociation of Cl2. © 2002 American Institute of Physics.
Show PACS
52.70.Kz Optical (ultraviolet, visible, infrared) measurements
52.77.Bn Etching and cleaning
52.25.-b Plasma properties
82.33.Xj Plasma reactions (including flowing afterglow and electric discharges)
81.65.Cf Surface cleaning, etching, patterning
07.60.Rd Visible and ultraviolet spectrometers

Comparison of a one-dimensional particle-in-cell–Monte Carlo model and a one-dimensional fluid model for a CH4/H2 capacitively coupled radio frequency discharge

Vladimir Ivanov, Olga Proshina, Tatyana Rakhimova, Alexander Rakhimov, Dieter Herrebout, and Annemie Bogaerts

J. Appl. Phys. 91, 6296 (2002); http://dx.doi.org/10.1063/1.1461895 (7 pages) | Cited 20 times

Online Publication Date: 13 May 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A one-dimensional particle-in-cell–Monte Carlo (PIC–MC) model was developed for a capacitively coupled rf discharge in a mixture of CH4 and H2. The electron behavior is kinetically simulated by solving Newton’s equations and treating the electron collisions with the Monte Carlo algorithm, whereas the behavior of the ions and radicals is treated by a set of continuity equations. The distinctive feature of this model is its self-consistency, i.e., the motion of the electrons is considered in the real electric field calculated from the Poisson equation, and not in the time-averaged electric field. The PIC–MC results were compared with the data calculated by means of a pure fluid model. In both models, exactly the same type of species, reactions, and cross sections are used. The results of both models, such as the electron energy distribution function, the average electron energy, and the densities of the various plasma species, are compared at a gas pressure of 0.14 Torr and a discharge frequency of 13.56 MHz, for the power ranging from 0.5 to 25 W. The nonstationary and nonlocal features of the electron energy distribution function are shown in the PIC–MC calculations. The effect of accumulation of low-energy electrons in the center of the discharge at higher input power P=25 W is observed in the PIC–MC model, in contrast with the fluid model. The mechanisms causing the accumulation of low-energy electrons, and the processes defining the stationary state of the discharge are analyzed. The applicability of the fluid model for the calculation of the density of different hydrocarbon radicals is discussed. © 2002 American Institute of Physics.
Show PACS
52.80.Pi High-frequency and RF discharges
52.65.Pp Monte Carlo methods

Measurements and modeling of ion energy distributions in high-density, radio-frequency biased CF4 discharges

Mark A. Sobolewski, Yicheng Wang, and Amanda Goyette

J. Appl. Phys. 91, 6303 (2002); http://dx.doi.org/10.1063/1.1467403 (12 pages) | Cited 25 times

Online Publication Date: 13 May 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Models of ion dynamics in radio-frequency (rf) biased, high-density plasma sheaths are needed to predict ion bombardment energies in plasma simulations. To test these models, we have measured ion energy distributions (IEDs) in pure CF4 discharges at 1.33 Pa (10 mTorr) in a high-density, inductively coupled plasma reactor, using a mass spectrometer equipped with an ion energy analyzer. IEDs of CF3+, CF2+, CF+, and F+ ions were measured as a function of bias frequency, bias amplitude, and inductive source power. Simultaneous measurements by a capacitive probe and a Faraday cup provide enough information to determine the input parameters of sheath models and allow direct comparison of calculated and measured IEDs. A rigorous and comprehensive test of one numerical sheath model was performed. The model, which includes a complete treatment of time-dependent ion dynamics in the sheath, was found to predict the behavior of measured IEDs to good accuracy over the entire range of bias frequency, including complicated effects that are observed when the ion transit time is comparable to the rf bias period. © 2002 American Institute of Physics.
Show PACS
52.70.Ds Electric and magnetic measurements
52.70.Nc Particle measurements
52.65.-y Plasma simulation
52.80.Pi High-frequency and RF discharges
52.40.Kh Plasma sheaths

Influence of the noble gas mixture composition on the performance of a plasma display panel

M. F. Gillies and G. Oversluizen

J. Appl. Phys. 91, 6315 (2002); http://dx.doi.org/10.1063/1.1465102 (6 pages) | Cited 35 times

Online Publication Date: 13 May 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The influence of the noble gas mixture composition on the plasma display panel performance is investigated in test panels with a design which resembles the one used in commercial panels. Single gases and binary and ternary mixtures of He, Ne, Ar, Kr, and Xe are applied, where the Xe concentration is varied from 0% to 100%. The performance is characterized in terms of the panel luminance, efficacy, and discharge voltages. It is found that while an increase in efficacy and luminance can be achieved in several multicomponent mixtures it is necessary to examine the associated increase in the firing voltage, Vf. If one considers the luminance versus Vf dependence, then binary NexXe1−x mixtures are optimal to achieve the highest efficacy values at the lowest Vf. The maximum efficacy gain factor in high Xe partial pressure mixtures is about a factor of 3 with respect to the mixture applied in default commercial panels. © 2002 American Institute of Physics.
Show PACS
85.60.Pg Display systems

Radiofrequency sustained double layer in a plasma reactor

B. M. Annaratone and J. E. Allen

J. Appl. Phys. 91, 6321 (2002); http://dx.doi.org/10.1063/1.1473670 (4 pages)

Online Publication Date: 13 May 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
This article presents experimental evidence of a coupling of power between the rf supply and a collisionless plasma in a capacitively coupled plasma reactor. The reactor is driven in plasma sheath resonance to let high rf currents circulate in the system. These currents allow the formation of strong rf fields inside the nonuniform plasma leading to a double layer with a mechanism similar to the rf plasma sheath at the electrodes. Electrons accelerated by the double layer are very effective in ionizing, because of the increased cross section, and create a dense plasma at low pressures. The power is consequently transferred by the ions accelerated in the electrode sheath to the substrate to be processed with high improvement in both performance and process rate. Diagnostics include a retarding field analyzer on the grounded electrode to measure the energy spectrum of ions hitting the substrate and a capacitive probe to obtain the rf potential variations in the plasma. © 2002 American Institute of Physics.
Show PACS
52.50.Qt Plasma heating by radio-frequency fields; ICR, ICP, helicons
52.40.Kh Plasma sheaths
52.25.-b Plasma properties
52.70.-m Plasma diagnostic techniques and instrumentation
52.20.-j Elementary processes in plasmas
back to top
RSS Feeds

Character of defects at an ion-irradiated buried thin-film interface

R. Kalyanaraman, T. E. Haynes, O. W. Holland, and G. H. Gilmer

J. Appl. Phys. 91, 6325 (2002); http://dx.doi.org/10.1063/1.1470258 (8 pages) | Cited 2 times

Online Publication Date: 13 May 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
In order to investigate the nature of defects produced by ion irradiation through a heterostructure, a silicon-on-insulator substrate with a buried SiO2 layer at a depth of ∼1.5 μm was irradiated. The implantation was done using 2 MeV 28Si+ ions in the dose range of 0.2–1×1016 cm−2. The subsequent defect analysis was performed using the Au labeling technique. Besides the presence of an expected excess of vacancy-type defects in the Si overlayer (VSiex), an additional vacancy excess peak was observed at the frontside of the buried interface (VIntex). The VIntex is found to increase linearly with increasing dose of the high-energy implant. The presence of this VIntex peak near the interface is also predicted by the TRIM Monte Carlo code. Additional Monte Carlo simulations of damage production via high-energy implantation in Si/X-type structures show that the nature of the defects at the front Si/X interface can be changed from vacancy to interstitial-type by increasing the mass of atoms in the buried thin-film, X. These experiments provide quantitative verification of nonuniform defect production at an ion-irradiated buried interface in Si. © 2002 American Institute of Physics.
Show PACS
61.80.Jh Ion radiation effects
68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.
61.72.J- Point defects and defect clusters
68.35.Dv Composition, segregation; defects and impurities
61.72.uf Ge and Si
02.70.Uu Applications of Monte Carlo methods

Analytical model for intrinsic residual stress effects and out-of-plane deflections in free-standing thick films

Jeung-hyun Jeong, Dongil Kwon, and Young-Joon Baik

J. Appl. Phys. 91, 6333 (2002); http://dx.doi.org/10.1063/1.1470257 (8 pages) | Cited 4 times

Online Publication Date: 13 May 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
An analytical model for the influence of residual stress on the out-of-plane deflection in a free-standing thick diamond film (the bowing phenomenon) is presented. The variation in residual stress with film thickness is usually believed to cause the bowing. In this study, the stress variation is assumed to be produced by a gradual increase in substrate deformation resulting from layer-by-layer deposition of the film. The model uses the infinitesimal plate-bending theory to describe the layer-by-layer film growth more exactly, considering the two deformation modes of contraction or expansion and bending. To verify the suggested model, thick diamond films were fabricated on Si, Mo, and W substrates of varying thicknesses by microwave plasma assisted chemical vapor deposition. The model’s predictions on bowing, based on the intrinsic stress value measured by the curvature method, were in good agreement with the bowing curvature of the as-released films measured by a profilometer. This confirms that the bowing of thick films depends on the intrinsic stress variation of the film associated with a gradual increase in substrate deformation. A method of eliminating bowing by depositing different layers with different intrinsic stresses is discussed. © 2002 American Institute of Physics.
Show PACS
68.60.Bs Mechanical and acoustical properties

Chemical composition dependences of the acoustical physical constants of LiNbO3 and LiTaO3 single crystals

J. Kushibiki, I. Takanaga, S. Komatsuzaki, and T. Ujiie

J. Appl. Phys. 91, 6341 (2002); http://dx.doi.org/10.1063/1.1467608 (9 pages) | Cited 3 times

Online Publication Date: 13 May 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We determined all the independent components of the acoustical physical constants (elastic constant, piezoelectric constant, dielectric constant, and density) of LiNbO3 and LiTaO3 crystals grown from the melts of three different starting materials with the Li2O contents set to 48.0, 48.5, and 49.0 mol %, and obtained the chemical composition dependences of the constants of each single crystal around the congruent composition. All the constants as well as the measured longitudinal, shear, and leaky surface acoustic wave (LSAW) velocities varied linearly with the composition ratios in the experimental range. The composition dependences of the LSAW velocities for the 128°YX-LiNbO3, X-112°Y-LiTaO3, and 36°YX-LiTaO3 substrates, previously obtained by line-focus-beam acoustic microscopy, were well matched with the calculated ones using the constants determined. Therefore the data of the composition dependences of the determined constants enable us to easily prepare the calibration lines for evaluating the crystals for any arbitrarily cut specimen surfaces, wave propagation directions, and modes by numerical calculations. © 2002 American Institute of Physics.
Show PACS
77.84.Ek Niobates and tantalates
77.84.Cg PZT ceramics and other titanates
77.65.Dq Acoustoelectric effects and surface acoustic waves (SAW) in piezoelectrics
77.22.Ch Permittivity (dielectric function)
68.35.Iv Acoustical properties
62.20.D- Elasticity
77.65.-j Piezoelectricity and electromechanical effects
62.65.+k Acoustical properties of solids
06.20.F- Units and standards

Photo-induced refractive index change in hydrogenated amorphous silicon oxynitride

Hiromitsu Kato, Makoto Fujimaki, Takashi Noma, and Yoshimichi Ohki

J. Appl. Phys. 91, 6350 (2002); http://dx.doi.org/10.1063/1.1461894 (4 pages) | Cited 2 times

Online Publication Date: 13 May 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Refractive index change is shown to be induced by the irradiation of ultraviolet photons in hydrogenated amorphous silicon oxynitride films prepared by plasma-enhanced chemical vapor deposition. The mechanism of the index change and its dependence on the nitrogen content were investigated by electron spin resonance and scanning electron microscopy. It is concluded that the index change is due mainly to densification, and that the contribution of the formation of paramagnetic defects is only slight. To demonstrate the versatility of this refractive index change, a planar diffraction grating was fabricated. © 2002 American Institute of Physics.
Show PACS
78.20.Ci Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity)
61.80.Ba Ultraviolet, visible, and infrared radiation effects (including laser radiation)
76.30.-v Electron paramagnetic resonance and relaxation
42.79.Dj Gratings
78.66.Nk Insulators

Dislocation evolution in 4H-SiC epitaxial layers

H. Jacobson, J. Birch, R. Yakimova, M. Syväjärvi, J. P. Bergman, A. Ellison, T. Tuomi, and E. Janzén

J. Appl. Phys. 91, 6354 (2002); http://dx.doi.org/10.1063/1.1468891 (7 pages) | Cited 26 times

Online Publication Date: 13 May 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
4H-SiC commercial wafers and sublimation grown epitaxial layers with a thickness of 100 μm have been studied concerning crystalline structure. The substrates and the epitaxial layers have been separately investigated by high-resolution x-ray diffraction and synchrotron white beam x-ray topography. The results show that the structural quality was improved in the epitaxial layers in the [11math0] and [math100] directions, concerning domain distribution, lattice plane misorientation, mosaicity, and strain, compared with the substrates. Misoriented domains have merged together to form larger domains while the tilt between the domains was reduced, which resulted in nonsplitting in diffraction curves. If the misorientation in the substrate is large, we can only see a slight decrease in the misorientation in the epilayer. At some positions on the substrates block structures (mosaicity) were observed. ω-rocking curves showed smaller full width at half maximum values and more uniform and narrow peaks, while the curvature was almost the same in grown epilayers compared with the corresponding substrates. We show that threading edge dislocations along the c axis in silicon carbide grown crystals transform to deflected dislocations in the epilayer. A formation mechanism for deflected dislocations and supporting facts are presented. We further show that these deflected dislocations are one possible source for the creation of stacking faults that recently has been reported to cause degradation in processed SiC bipolar diodes. © 2002 American Institute of Physics.
Show PACS
68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.
61.72.Ff Direct observation of dislocations and other defects (etch pits, decoration, electron microscopy, x-ray topography, etc.)

Chemical bonding of nitrogen in low energy high flux implanted austenitic stainless steel

J. P. Riviere, M. Cahoreau, and P. Meheust

J. Appl. Phys. 91, 6361 (2002); http://dx.doi.org/10.1063/1.1469691 (6 pages) | Cited 20 times

Online Publication Date: 13 May 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
AISI 304L austenitic stainless steel was implanted at 400 °C with 1.2 keV nitrogen ions using a high beam current density of 1 mA/cm2. The nitrogen depth profile, structure, and chemical composition in the modified surface layer were determined by nuclear reaction analysis (NRA) and x-ray diffraction (XRD). The chemical bonding of Fe, Cr atoms with nitrogen was investigated by x-ray photoelectron spectroscopy (XPS). For a treatment time of 1 h, the formation of a thick nitrided layer of about 3.5 μm with a high nitrogen content (∼20 at. %) is observed by NRA. The nitrogen depth profile is characterized by a nearly flat shape over a thickness of 2.5 μm followed by an abrupt decrease. XRD spectra show the formation in the nitrided layer of a phase usually called expanded austenite γN, which corresponds fairly well with a nitrogen solid solution of the fcc structure containing a high density of stacking faults. The XPS study of the Cr 2p3/2, Fe 2p3/2, and N 1s binding states indicate clearly the preferential bonding of chromium with nitrogen with a binding energy of about 1 eV. This value, which is lower than the expected one for chromium nitride CrN, would be characteristic of the binding energy of nitrogen with Cr in the γN expanded austenite phase. Moreover, it has been found that the atomic ratio N/Cr in the nitride layer deduced from both NRA and XPS is very close to 1. These experimental results support the specific role of chromium in the mechanisms of atomic transport of nitrogen over long distances at moderate temperature in austenitic stainless steels. © 2002 American Institute of Physics.
Show PACS
81.65.Lp Surface hardening: nitridation, carburization, carbonitridation
61.82.Bg Metals and alloys
61.80.Jh Ion radiation effects
68.35.Dv Composition, segregation; defects and impurities
61.72.up Other materials
61.50.Lt Crystal binding; cohesive energy
68.49.Uv X-ray standing waves
61.72.Nn Stacking faults and other planar or extended defects
68.35.B- Structure of clean surfaces (and surface reconstruction)
82.80.-d Chemical analysis and related physical methods of analysis

Picosecond amplified spontaneous emission bursts from a molecularly doped organic semiconductor

C. Kallinger, S. Riechel, O. Holderer, U. Lemmer, J. Feldmann, S. Berleb, A. G. Mückl, and W. Brütting

J. Appl. Phys. 91, 6367 (2002); http://dx.doi.org/10.1063/1.1466879 (4 pages) | Cited 6 times

Online Publication Date: 13 May 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We report the dynamics of amplified spontaneous emission (ASE) in thin organic films of tris-(8-hydroxyquinoline)-aluminum (Alq3) doped with small amounts of the laser dye 4-dicyanmethylene-2-methyl-6-(p-dimethylaminostyryl)-4H-pyran (DCM). The energy transfer from the initially photoexcited Alq3 to the DCM molecules affects the high excitation density dynamics significantly. The time delay between pulsed photoexcitation and the ASE burst depends on the pumping level. For higher pumping levels the competition between depopulation by ASE and refilling of the DCM states via energy transfer leads to an oscillatory emission with a fundamental frequency of up to 0.2 THz. © 2002 American Institute of Physics.
Show PACS
78.66.Qn Polymers; organic compounds
78.45.+h Stimulated emission
71.20.Rv Polymers and organic compounds
78.47.-p Spectroscopy of solid state dynamics

Molecular beam epitaxial growth of SrCu2O3: Metastable structures and the role of epitaxy

N. J. C. Ingle, R. H. Hammond, and M. R. Beasley

J. Appl. Phys. 91, 6371 (2002); http://dx.doi.org/10.1063/1.1466876 (8 pages) | Cited 3 times

Online Publication Date: 13 May 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Within the study of oxide materials, high pressure bulk growth has generated a number of new and interesting materials. More recently, attention has been paid to using epitaxy to stabilize these high pressure oxide materials as thin films. In this article we report on the molecular beam epitaxial growth of SrCu2O3; a high pressure, highly correlated, model oxide. We find that the choice of substrate can significantly alter not only the structure but also the chemistry of the resulting film. For growth on SrTiO3 substrates the epitaxially stabilized structure for single phase films with a SrCu2O3 composition is based on a tetragonal unit cell. For identical growth conditions, but on a LaAlO3 substrate, a single phase film with the composition and structure of the infinite layer material (SrCuO2) is formed. We also review the literature for the successes and failures of epitaxy to stabilize high pressure structures. © 2002 American Institute of Physics.
Show PACS
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
68.55.A- Nucleation and growth
68.55.Nq Composition and phase identification
68.55.-a Thin film structure and morphology
62.50.-p High-pressure effects in solids and liquids
61.66.Fn Inorganic compounds
01.30.Rr Surveys and tutorial papers; resource letters

Elastic and piezoelectric fields in substrates GaAs (001) and GaAs (111) due to a buried quantum dot

E. Pan

J. Appl. Phys. 91, 6379 (2002); http://dx.doi.org/10.1063/1.1468906 (9 pages) | Cited 24 times

Online Publication Date: 13 May 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
In this article we present a rigorous study on the elastic and piezoelectric fields in substrates GaAs (001) and GaAs (111) due to a buried quantum dot (QD) using an efficient and accurate continuum mechanics model. It is based on a Green’s function solution in anisotropic and linearly piezoelectric half space combined with the generalized Betti reciprocal theorem. To address the effect of material anisotropy, two other substrates, Iso (001) and Iso (111), are also examined and they are assumed to be elastically isotropic. For a point QD with hydrostatic misfit strain γ∗=0.07 in volume va=4πa3/3 where a=3 nm, and at depth h=10 nm below the surface, we have observed the following features. (1) The simplified elastically isotropic model should, in general, not be used for predicting elastic and piezoelectric fields in the semiconductor GaAs. (2) The magnitude of the QD-induced piezoelectric potential on the surface of GaAs (111) or GaAs (001) is comparable to, or even larger than, the direct potential. (3) Large horizontal and vertical electric fields, on the order of 106 V/m, can be induced on the surface of GaAs (001) and GaAs (111). (4) The elastic field induced on the surface of GaAs (001) has rotational symmetry of order C4 (i.e., the elastic field remains the same after rotation of 2π/4 around the [001] axis), while the corresponding piezoelectric field has rotational symmetry of order C2. On the other hand, both the elastic and piezoelectric fields on the surface of GaAs (111) have rotational symmetry of C3 around the [111] axis. (5) The magnitude of the elastic and piezoelectric quantities on the surface of GaAs (111) is, in general, larger than that of the corresponding quantities on the surface of GaAs (001). (6) Under different electric surface conditions (insulating or conducting), the surface piezoelectric fields induced are quite different. © 2002 American Institute of Physics.
Show PACS
77.65.-j Piezoelectricity and electromechanical effects
73.63.Kv Quantum dots
68.35.Gy Mechanical properties; surface strains
68.65.Hb Quantum dots (patterned in quantum wells)
62.20.D- Elasticity

Damage evolution and recovery on both Si and C sublattices in Al-implanted 4H–SiC studied by Rutherford backscattering spectroscopy and nuclear reaction analysis

Y. Zhang, W. J. Weber, W. Jiang, A. Hallén, and G. Possnert

J. Appl. Phys. 91, 6388 (2002); http://dx.doi.org/10.1063/1.1469204 (8 pages) | Cited 30 times

Online Publication Date: 13 May 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Damage evolution and subsequent recovery in 4H–SiC epitaxial layers irradiated with 1.1 MeV Al22+ molecular ions at 150 K to ion fluences from 1.5×1013 to 2.25×1014 Al cm−2 were studied by Rutherford backscattering spectroscopy (RBS) and 12C(d,p)13C nuclear reaction analysis (NRA) using a 0.94 MeV deuterium (D+) beam in channeling geometry. Disorder on both the Si and C sublattices was measured simultaneously from the RBS scattering and NRA reaction yields. The relative disorder on both sublattices follows a nonlinear dependence on ion fluence that is consistent with a model based on simple defect accumulation and a direct-impact, defect-stimulated process for amorphization. At low ion fluences, the relative disorder on the C sublattice is higher than that on the Si sublattice. Isochronal annealing up to 870 K revealed the existence of three distinct recovery stages at ∼350, 520, and 650 K for low to intermediate damage levels. In highly damaged samples, where a buried amorphous layer is produced, the onset of a fourth recovery stage appears above 800 K. Similar recovery behaviors on both the Si and C sublattices suggests some coupling of recovery processes for Si and C defects. © 2002 American Institute of Physics.
Show PACS
68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.
61.80.Jh Ion radiation effects
61.82.Fk Semiconductors
61.72.up Other materials
61.85.+p Channeling phenomena (blocking, energy loss, etc.)
82.80.Yc Rutherford backscattering (RBS), and other methods of chemical analysis
61.72.Cc Kinetics of defect formation and annealing

Copper precipitates in silicon: Precipitation, dissolution, and chemical state

Scott A. McHugo, A. Mohammed, A. C. Thompson, B. Lai, and Z. Cai

J. Appl. Phys. 91, 6396 (2002); http://dx.doi.org/10.1063/1.1471944 (10 pages) | Cited 6 times

Online Publication Date: 13 May 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The precipitation and dissolution of copper impurities at oxygen precipitates and stacking faults in silicon were studied using thermal budgets commensurate with standard integrated circuit processing. Additionally, in order to develop a better understanding of the dissolution process, we have obtained results on the chemical state of the copper precipitates. The goal of this work was to determine the feasibility of removing and maintaining copper impurities away from the active device region of an integrated circuit device by use of oxygen precipitates and stacking faults in the bulk of the material. Based on our results, we provide a basis for a predictive understanding of copper precipitation and dissolution in silicon and we discuss the feasibility of copper impurity control in silicon integrated circuit devices. © 2002 American Institute of Physics.
Show PACS
81.05.Cy Elemental semiconductors
81.65.Tx Gettering
64.75.-g Phase equilibria
61.72.Nn Stacking faults and other planar or extended defects
61.72.Yx Interaction between different crystal defects; gettering effect

Temperature discontinuity at the surface of an evaporating droplet

A. J. H. McGaughey and C. A. Ward

J. Appl. Phys. 91, 6406 (2002); http://dx.doi.org/10.1063/1.1471363 (10 pages) | Cited 17 times

Online Publication Date: 13 May 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
In a series of experiments, a temperature discontinuity has been found to exist at the surface of an evaporating water droplet. Statistical rate theory has been used to predict the pressure in the vapor to within the experimental uncertainty during each of the experiments. While the qualitative trend of the D2 law is observed to be consistent with the measurements, it underpredicts the measured rate of evaporation by 21%–37%. When the temperature discontinuity is taken into account in the D2 law, the difference between the predicted and measured values is at most 7%. The results suggest that the rate limiting process in the experiments is not diffusion in the gas phase, as is assumed in the D2 law, but is the interface kinetics. © 2002 American Institute of Physics.
Show PACS
64.70.F- Liquid-vapor transitions
47.55.D- Drops and bubbles

Compositional intermixing at CdS/Cu(In,Ga)Se2 rough interface studied by x-ray fluorescence

S. Kim, Y. L. Soo, G. Kioseoglou, Y. H. Kao, K. Ramanathan, and S. K. Deb

J. Appl. Phys. 91, 6416 (2002); http://dx.doi.org/10.1063/1.1471388 (7 pages) | Cited 3 times

Online Publication Date: 13 May 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The effects of compositional intermixing and high interfacial roughness in a series of CdS/Cu(In,Ga)Se2 heterojunctions have been investigated using the technique of angular dependence of x-ray fluorescence. In the present case, the average interfacial roughness actually exceeds the nominal thickness of CdS film. A method of data analysis has been worked out to account for the large roughness and this technique allows a possibility of nondestructive determination of the concentration profile of both CdS and Cu(In,Ga)Se2 as well as the effective roughness parameters in the system. © 2002 American Institute of Physics.
Show PACS
68.35.Ct Interface structure and roughness
68.35.Fx Diffusion; interface formation
82.80.Ej X-ray, Mössbauer, and other γ-ray spectroscopic analysis methods
66.30.Ny Chemical interdiffusion; diffusion barriers

Persistent spectral hole burning in chalcohalide glasses doped with Eu3+

Woon Jin Chung and Jong Heo

J. Appl. Phys. 91, 6423 (2002); http://dx.doi.org/10.1063/1.1467964 (5 pages)

Online Publication Date: 13 May 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Efficient persistent spectral hole burning in Eu3+-doped sulfide glasses was observed with the addition of CsBr or KBr. Holes in these glasses showed high initial growth rates, thermal barrier heights, and low relaxation rates. It was also possible to form independent multiholes on the inhomogeneously broadened absorption spectrum. One-photon absorption of the burning light and corresponding reduction of Eu3+ into Eu2+ via interaction with local conduction (or charge transfer) bands are the main processes for hole burning. © 2002 American Institute of Physics.
Show PACS
42.50.Md Optical transient phenomena: quantum beats, photon echo, free-induction decay, dephasings and revivals, optical nutation, and self-induced transparency
78.40.Pg Disordered solids
71.70.-d Level splitting and interactions
71.55.Jv Disordered structures; amorphous and glassy solids
61.43.Fs Glasses

Investigation of the interlayer characteristics of Ta2O5 thin films deposited on bare, N2O, and NH3 plasma nitridated Si substrates

Yi-Sheng Lai, Kuan-Jen Chen, and J. S. Chen

J. Appl. Phys. 91, 6428 (2002); http://dx.doi.org/10.1063/1.1471926 (7 pages) | Cited 17 times

Online Publication Date: 13 May 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Low-temperature N2O and NH3 plasma nitridations on Si surfaces are conducted to prevent the thermodynamic instability at the Ta2O5/Si interface. The surface and interface of the Ta2O5/Si systems, without or with nitridation, were examined by x-ray photoelectron spectroscopy (XPS), atomic force microscopy, transmission electron microscopy, and secondary ion mass spectrometry. Capacitance–voltage (C–V) measurements were carried out to investigate the electric/defect characteristics of the Ta2O5/Si systems. For the non-nitrided Si substrate XPS detects no surface oxide formed prior to Ta2O5 deposition. In contrast, NH3 plasma nitridation forms a nitrogen-rich SiOxNy layer, while N2O plasma nitridation produces an oxygen-rich SiOxNy layer on Si. C–V measurement reveals high densities of fixed charges, trapping sites, and interface states in the Ta2O5/non-nitrided Si sample, indicative that a defective interlayer was formed during Ta2O5 deposition. Ta2O5 on both nitrided systems exhibits a reduced amount of fixed charges and trapping sites. Nevertheless, NH3 plasma nitridation is not as effective as N2O plasma nitridation in diminishing the density of interface states. The different electric/defect characters between the NH3 and N2O nitrided systems are attributed to the further oxidation of the nitrogen-rich SiOxNy layer produced by NH3 plasma nitridation, which induces defects at the dielectric/Si interface. Effectiveness of the nitridation process, therefore, depends on the stability of the nitrided layer during deposition of Ta2O5. © 2002 American Institute of Physics.
Show PACS
73.40.Qv Metal-insulator-semiconductor structures (including semiconductor-to-insulator)
81.65.Lp Surface hardening: nitridation, carburization, carbonitridation
81.05.Cy Elemental semiconductors
81.05.Je Ceramics and refractories (including borides, carbides, hydrides, nitrides, oxides, and silicides)
71.55.Ht Other nonmetals
52.77.Dq Plasma-based ion implantation and deposition
79.60.Jv Interfaces; heterostructures; nanostructures
68.37.Ps Atomic force microscopy (AFM)
68.37.Lp Transmission electron microscopy (TEM)
68.60.Dv Thermal stability; thermal effects
81.65.Mq Oxidation
73.50.Gr Charge carriers: generation, recombination, lifetime, trapping, mean free paths
73.20.At Surface states, band structure, electron density of states
73.20.Hb Impurity and defect levels; energy states of adsorbed species
Page 1 of 31 Pages Next Page | Jump to Page
Close

Google Calendar

ADVERTISEMENT

Your Recent History Recent History Help

Recently Viewed

  1. Lattice softening and failure in severely deformed molecular crystals
  2. Nanocrystalline iron at high pressure
  3. Improved refractive index formulas for the AlxGa1−xN and InyGa1−yN alloys
  4. Band parameters for III–V compound semiconductors and their alloys
  5. Rate and efficiency of spontaneous emission in metal-clad microcavities
Go to AIP Home
Copyright © American Institute of Physics
close