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 Jul 2000

Volume 88, Issue 2, pp. 605-1196

Return to All Sections
back to top
RSS Feeds

Laser coloration and bleaching of amorphous WO3 thin film

Y. F. Lu and H. Qiu

J. Appl. Phys. 88, 1082 (2000); http://dx.doi.org/10.1063/1.373780 (6 pages) | Cited 16 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Laser-induced chromism of amorphous WO3 thin films prepared by pulsed laser deposition (PLD) has been investigated. The original films could be colored from light brown to purple by a single pulse of KrF excimer laser irradiation at 248 nm and subsequently bleached to brown by a single pulse of Nd–yttrium–aluminum–garnet laser at 1.06 μm in air. Spectroscopic investigations were applied to the films at three different states: original, colored, and bleached. The measurements by ellipsometry spectroscopy showed an increase in the refractive index (n) and decrease in extinction coefficient (k) in the luminous range of films from the colored state to the bleached state. Scanning tunneling microscopy and Raman spectroscopy showed slight crystallization in the films after coloration, with both the grain dimension and the surface roughness around tens of nanometers. The films were very stable to maintain the same color after long-time exposure in air, or in oxygen. X-ray photoelectron spectroscopy was used to study the chromism mechanisms. While some W5+ states were introduced in the original films by PLD, W4+ states were produced when the films were colored by the KrF excimer laser, along with the decrease of W5+ states and the increase of W6+ states. In contrast, laser bleaching was accompanied with increasing W4+ states in the films. Therefore, it is believed that the purple color is due to the polaron transition between the W4+ and W5+ states. Photochemical activation and photothermal oxidation are ascribed to the coloring and the bleaching processes, respectively. © 2000 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
61.43.Er Other amorphous solids
78.20.Ci Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity)
78.35.+c Brillouin and Rayleigh scattering; other light scattering
61.80.Ba Ultraviolet, visible, and infrared radiation effects (including laser radiation)
71.38.-k Polarons and electron-phonon interactions
82.50.-m Photochemistry

Characterization of ZrO2/Y2O3 laser ablation plasma in vacuum, oxygen, and argon environments

A. A. Voevodin, J. G. Jones, and J. S. Zabinski

J. Appl. Phys. 88, 1088 (2000); http://dx.doi.org/10.1063/1.373781 (9 pages) | Cited 20 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Laser ablation deposition of highly oriented yttria stabilized zirconia (YSZ) films is important for various technological applications and depends critically on the selection of background environment, with low pressure oxygen being the most common choice. Here, the spatial-temporal distribution of YSZ plume chemistry, excitation states, and energy was determined for ablations in vacuum, low pressure O2, and low pressure Ar, using fluorescence analyses, element specific imaging techniques, and time-of-flight experiments. It was found that an Ar background considerably promotes excitation and ionization of zirconium during the first 1–3 μs after the laser strike. There is much less zirconium excitation in an O2 background, where a large fraction of atomic oxygen with a broad spatial distribution was found. ZrO and YO molecules were observed in both environments. Their highest concentrations were in the O2 background, where fluorescence from these molecules near the substrate lasted for 2–5 μs. Neutral species in YSZ plumes were fitted to Maxwellian type velocity distributions with a shifted center of mass. Kinetic energies derived from the fitted data were reduced by about a factor of 2 in Ar and O2 backgrounds compared to in vacuum. This was not observed for Zr1+ species, which maintained about 100–120 eV mean kinetic energy nearly independently of the background. The ionization of Zr in the presence of Ar, the high velocity of ionized Zr atoms relative to the rest of the plume, the generation of molecular ZrO, YO, and atomic oxygen in the presence of O2 are potentially important for chemistry and structure control of YSZ films. © 2000 American Institute of Physics.
Show PACS
79.20.Ds Laser-beam impact phenomena
52.70.-m Plasma diagnostic techniques and instrumentation
81.15.Fg Pulsed laser ablation deposition
61.82.Ms Insulators

Electron microscopy and Rutherford backscattering study of nucleation and growth in nanosized W–Ti–O thin films

M. Ferroni, V. Guidi, G. Martinelli, E. Comini, G. Sberveglieri, D. Boscarino, and G. Della Mea

J. Appl. Phys. 88, 1097 (2000); http://dx.doi.org/10.1063/1.373782 (7 pages) | Cited 9 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Structural characterization of nanosized W–Ti–O rf magnetron-sputtered films was carried out by means of electron microscopy techniques and Rutherford backscattering spectroscopy. The evolution of the W–Ti–O films turned out to be quite complex as several nanophases were determined. Depending on annealing temperature and W/Ti abundance, stable nanophases of WO3, TiO, and TiO2 have been reliably achieved. The investigation highlighted the reason why the films remained nanostructured in spite of a relatively high annealing temperature. In fact, formation of a dispersed TiO nanophase in the W–Ti–O layers was recognized to inhibit grain growth and promote secondary recrystallization. This resulted in exaggerated growth of WO3 crystallites over the nanostructured layers. © 2000 American Institute of Physics.
Show PACS
68.55.-a Thin film structure and morphology
68.55.Nq Composition and phase identification
61.46.-w Structure of nanoscale materials
81.07.-b Nanoscale materials and structures: fabrication and characterization
68.37.Hk Scanning electron microscopy (SEM) (including EBIC)
68.37.Lp Transmission electron microscopy (TEM)
82.80.Yc Rutherford backscattering (RBS), and other methods of chemical analysis
64.60.Q- Nucleation
81.10.Jt Growth from solid phases (including multiphase diffusion and recrystallization)
81.40.Ef Cold working, work hardening; annealing, post-deformation annealing, quenching, tempering recovery, and crystallization
61.72.Mm Grain and twin boundaries

Theoretical analysis of unstable two-phase region and microscopic structure in wurtzite and zinc-blende InGaN using modified valence force field model

Toru Takayama, Masaaki Yuri, Kunio Itoh, Takaaki Baba, and James S. Harris

J. Appl. Phys. 88, 1104 (2000); http://dx.doi.org/10.1063/1.373783 (7 pages) | Cited 22 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A model to predict material characteristics of the InGaN ternary system, which is useful for blue and green light emitting and laser diodes, with respect to an unstable two-phase region in the phase field and the first neighbor anion–cation bond length is developed. The unstable region is analyzed using a strictly regular solution model. The interaction parameter used in the analysis is obtained from a strain energy calculation using the valence force field (VFF) model, modified for both wurtzite and zinc-blende structures to avoid overestimation of the strain energy. The structural deviation from an ideal wurtzite structure in GaN and InN is also taken into account in our model. The critical temperatures found in our analysis for wurtzite InGaN and zinc-blende InGaN are 1967 and 1668 K, respectively. This suggests that, at typical growth temperatures around 800 °C, a wide unstable two-phase region exists in both wurtzite and zinc-blende structures. The modified VFF model can also predict the microscopic crystal structure, such as first neighbor anion–cation bond lengths. In order to validate our calculation results for zinc-blende structures, we compare the calculated and the experimental results in terms of the interaction parameter and the first neighbor anion–cation bond lengths in the InGaAs system. For the wurtzite structure, we compare the calculated and the experimental results for the first neighbor anion–cation bond lengths in the InGaN system. The calculated results agree well with the experimental results. © 2000 American Institute of Physics.
Show PACS
62.20.-x Mechanical properties of solids
64.70.K- Solid-solid transitions

Simulation of trench homogeneity in plasma immersion ion implantation

G. Keller, U. Rüde, L. Stals, S. Mändl, and B. Rauschenbach

J. Appl. Phys. 88, 1111 (2000); http://dx.doi.org/10.1063/1.373784 (7 pages) | Cited 19 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The time-dependent evolution of the potential, the electrical field, and the particle movement surrounding two-dimensional trenches during a high voltage pulse in the context of plasma immersion ion implantation is studied by a particle-in-cell simulation. The numerical procedure is based on the solution of Poisson‘s equation on a grid and the determination of the movement of the particles on the grid. This simulation is combined with simulation codes for the calculation of depth profiles and sputtering yields. The retained ion dose and the depth resolved concentration distribution were determined in dependence on the rise time of the pulse between 0.1 and 2 μs, pulse durations between 1 and 10 μs and the ion mass (m=20–131, i.e., Ne,…,Xe) for trenches with two different aspect ratios (η=3:1 and 3:2). The results are discussed on the basis of the temporal evolution of the energy of the ions and the impact angle of the ions during the pulse. © 2000 American Institute of Physics.
Show PACS
61.72.uf Ge and Si
61.72.uj III-V and II-VI semiconductors
61.72.up Other materials
61.80.Jh Ion radiation effects
61.82.Fk Semiconductors
52.77.Bn Etching and cleaning
52.77.Dq Plasma-based ion implantation and deposition
81.65.Cf Surface cleaning, etching, patterning
61.72.S- Impurities in crystals

Depleted semi-insulating silicon/silicon material formed by wafer bonding

Mikael Johansson and Stefan Bengtsson

J. Appl. Phys. 88, 1118 (2000); http://dx.doi.org/10.1063/1.373785 (6 pages)

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Wafer bonding has been used to manufacture a silicon material intended as substrate for high-frequency applications. The space charge regions surrounding the bonded silicon/silicon interface deplete the silicon, thereby causing semi-insulating behavior at high frequencies. The material has been characterized electrically for frequencies up to 40 GHz using metal transmission lines on its surface. The results show that transmission lines made on these materials show low losses when signals are transmitted along them. These results have been compared to measurements using similar transmission lines on bulk silicon wafers of different resistivities, on SIMOX wafers, and on quartz. © 2000 American Institute of Physics.
Show PACS
73.40.Lq Other semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions
81.05.Cy Elemental semiconductors
77.22.Jp Dielectric breakdown and space-charge effects
72.30.+q High-frequency effects; plasma effects
73.40.Ns Metal-nonmetal contacts

Transmission electron microscopy structure and platinum-like temperature coefficient of resistance in a ruthenate-based thick film resistor with copper oxide

J. C. Jiang, Gary M. Crosbie, W. Tian, K. K. Cameron, and X. Q. Pan

J. Appl. Phys. 88, 1124 (2000); http://dx.doi.org/10.1063/1.373786 (5 pages) | Cited 2 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
As an alternative to thin-film platinum temperature sensor elements, thick film resistor ones are of interest for circuits which can withstand a near-engine environment. From a pyrochlore paste (DuPont 5091D), a close match is obtained (after firing) to the positive temperature coefficient of resistance (TCR) of Pt. Within the glassy matrix during 850 °C firing, needle-like RuO2 grains grow by a mechanism consistent with periodic bond chain theory. The acicular growth habit is attributed to a Cu2O additive, which is assumed to oxidize upon firing. The needles provide direct paths for metallic conduction and a characteristic positive TCR to the thick film in spite of having a low RuO2 volume fraction. © 2000 American Institute of Physics.
Show PACS
84.32.Ff Conductors, resistors (including thermistors, varistors, and photoresistors)
85.40.Xx Hybrid microelectronics; thick films
07.20.Dt Thermometers
61.72.-y Defects and impurities in crystals; microstructure
72.80.Tm Composite materials

Molecular-dynamics simulations of steady-state growth of ion-deposited tetrahedral amorphous carbon films

H. U. Jäger and K. Albe

J. Appl. Phys. 88, 1129 (2000); http://dx.doi.org/10.1063/1.373787 (7 pages) | Cited 63 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Molecular-dynamics calculations were performed to simulate ion beam deposition of diamond-like carbon films. Using the computationally efficient analytical potentials of Tersoff and Brenner we are able to simulate more than 103 carbon atom impacts on {111} diamond, so that steady-state film properties can be computed and analyzed. For the Tersoff potential, we achieve sp3 fractions approximately half of the experimentally observed values. For the more refined hydrocarbon potentials of Brenner the fraction of tetrahedrally coordinated atoms is much too low, even if structures with densities close to diamond are obtained. We show, that the sp3 contents calculated with Tersoff’s potential are an artifact related to the overbinding of specific bonding configurations between three- and fourfold coordinated sites. On the other hand, we can prove, that the range for the binding orbitals represented by the cutoff function is too short in Brenner’s parametrization. If an increased C–C interaction cutoff value is chosen, we achieve a distinct improvement in modeling the sp3 content of deposited ta-C films. As a result we compute sp3 fractions which lie between 52% and 95% for the C+ ion energies E=30–80 eV and are in reasonable agreement with recent experimental studies. © 2000 American Institute of Physics.
Show PACS
61.43.Bn Structural modeling: serial-addition models, computer simulation
81.15.Aa Theory and models of film growth
81.15.Jj Ion and electron beam-assisted deposition; ion plating
61.43.Er Other amorphous solids
68.55.-a Thin film structure and morphology

Basic properties of GaAs oxide generated by scanning probe microscope tip-induced nano-oxidation process

Yoshitaka Okada, Yoshimasa Iuchi, Mitsuo Kawabe, and James S. Harris

J. Appl. Phys. 88, 1136 (2000); http://dx.doi.org/10.1063/1.373788 (5 pages) | Cited 18 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The basic properties of GaAs oxide generated by atomic force microscope (AFM) tip-induced nano-oxidation process have been investigated. The chemical analysis of the AFM tip-generated GaAs oxide was performed by using scanning microprobe x-ray photoelectron spectroscopy, and the main constituents of GaAs anodic oxide were determined to be Ga2O3 and As2O3. The electrical characterization showed that the electron transport across a GaAs oxide nanodot of ∼5.7 nm thickness, from a doped n+-Si tip into the n+-GaAs substrate follows the Fowler–Nordheim tunneling mechanism over a range of applied bias. Further, the tip-generated GaAs oxide nanodots were found to withstand moderate thermal treatments, but some volume reduction was observed. © 2000 American Institute of Physics.
Show PACS
73.61.Ey III-V semiconductors
79.60.Bm Clean metal, semiconductor, and insulator surfaces
73.21.-b Electron states and collective excitations in multilayers, quantum wells, mesoscopic, and nanoscale systems

Relation between the suppression of the generation of stacking faults and the mechanism of silicon oxidation during annealing under argon containing oxygen

Toshiharu Suzuki

J. Appl. Phys. 88, 1141 (2000); http://dx.doi.org/10.1063/1.373789 (8 pages) | Cited 5 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The effect of the oxygen partial pressure during annealing under argon on the generation and growth of defects that adversely affect the yield and reliability of thermally grown oxide was investigated by precisely and widely controlling the oxygen partial pressure. Below the critical oxygen partial pressure of 6×10−3 atm, the generation of oxidation-induced stacking faults (OSFs) during a subsequent oxidation step was effectively suppressed from the density of about 103 cm−2 to less than 20 cm−2. Annealing for 10 min under an appropriate oxygen partial pressure was shown to be sufficient for annihilation of the origin of OSF and this effect continued even during a subsequent oxidation in dry oxygen. Mechanism by which the generation of OSFs is suppressed was discussed considering the oxidation mechanism under the reduced oxygen partial pressures. It is suggested that electric field that builds across the oxide layer when the oxygen partial pressure is below the critical value causes silicon interstitials and impurities such as metals to drift from the substrate to the outer surface of the oxide. During the annealing origins of OSFs such as Si–O clusters and metallic impurities are eliminated and mechanical damage is also annealed out before climbing to be the nuclei of OSFs. © 2000 American Institute of Physics.
Show PACS
81.65.Mq Oxidation
61.72.Nn Stacking faults and other planar or extended defects
61.72.Cc Kinetics of defect formation and annealing
81.05.Cy Elemental semiconductors

Influence of nitrogen and temperature on the deposition of tetrahedrally bonded amorphous carbon

B. Kleinsorge, A. C. Ferrari, J. Robertson, and W. I. Milne

J. Appl. Phys. 88, 1149 (2000); http://dx.doi.org/10.1063/1.373790 (9 pages) | Cited 51 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The effect of nitrogen addition on the properties of tetrahedral amorphous carbon (ta-C) has been studied. The ta-C is deposited by a filtered cathodic vacuum arc. The effect of introducing nitrogen on its plasma was measured by a retarding field analyzer and optical emission spectroscopy. The ta-C:N films were studied as a function of nitrogen content, ion energy, and deposition temperature. The incorporation of nitrogen was measured over the range of 10−2–10 at. % by secondary ion mass spectrometry and elastic recoil detection analysis. The N content was found to vary slightly sublinearly with the N2 partial pressure during deposition. A doping regime was found for N contents of up to 0.4 at. %, in which the conductivity changes while the sp3 content and the optical band gap remain constant. For 0.4%–8% N, the sp3 fraction remains above 80% but the optical gap closes due to a clustering of sp2 sites. Only above about 10% N, the sp3 fraction falls. The influence of nitrogen on the a-C was found to be independent of ion energies between 20 and 220 eV. Deposition above 200 °C causes a sudden loss of sp3 bonding. Raman and optical gap data show however that existing sp2 sites begin to cluster below this temperature. © 2000 American Institute of Physics.
Show PACS
81.15.Kk Vapor phase epitaxy; growth from vapor phase
68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.
73.61.Jc Amorphous semiconductors; glasses
78.66.Jg Amorphous semiconductors; glasses
61.43.Dq Amorphous semiconductors, metals, and alloys
81.05.Gc Amorphous semiconductors
52.77.Bn Etching and cleaning
52.77.Dq Plasma-based ion implantation and deposition
82.80.Ms Mass spectrometry (including SIMS, multiphoton ionization and resonance ionization mass spectrometry, MALDI)
78.35.+c Brillouin and Rayleigh scattering; other light scattering
78.66.Db Elemental semiconductors and insulators
73.61.Cw Elemental semiconductors
71.23.Cq Amorphous semiconductors, metallic glasses, glasses

Growth mode and surface morphology of a GaN film deposited along the N-face polar direction on c-plane sapphire substrate

M. Sumiya, K. Yoshimura, T. Ito, K. Ohtsuka, S. Fuke, K. Mizuno, M. Yoshimoto, H. Koinuma, A. Ohtomo, and M. Kawasaki

J. Appl. Phys. 88, 1158 (2000); http://dx.doi.org/10.1063/1.373791 (8 pages) | Cited 52 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The dependence of polar direction of GaN film on growth conditions has been investigated by changing either the group-V/group-III ratio (V/III ratio) in supplying the source gas or the deposition rate. GaN films were deposited on a nitrided sapphire by two-step metalorganic chemical vapor deposition. The surface morphology changed from flat hexagonal to pyramidal hexagonal facet with the increase of V/III ratio. However, the polar direction of GaN on an optimized buffer layer of 20 nm thickness was N-face (−c) polarity, independent of both the V/III ratio and the deposition rate. The polarity of the GaN epitaxtial layer can be determined by that of an interface (nitrided sapphire, annealed buffer layer or GaN substrate) at the deposition of GaN epitaxial layer. The higher V/III ratio enhanced the nucleation density, and reduced the size of hexagonal facets. The nuclei, forming the favorable hexagonal facets of wurtzite GaN, should grow laterally along the {10math0} directions to cover a room among the facets until coalescence. After coalescence, −c GaN growth on a flat hexagonal facet results in a pyramidal hexagonal facet. The growth mode for −c GaN has been discussed with respect to surface structure and migration length of adsorbing precursors, in comparison with Ga-face (+c) GaN. © 2000 American Institute of Physics.
Show PACS
68.55.-a Thin film structure and morphology
81.05.Ea 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
68.35.B- Structure of clean surfaces (and surface reconstruction)

Using the flowing afterglow of a plasma to inactivate Bacillus subtilis spores: Influence of the operating conditions

S. Moreau, M. Moisan, M. Tabrizian, J. Barbeau, J. Pelletier, A. Ricard, and L’H. Yahia

J. Appl. Phys. 88, 1166 (2000); http://dx.doi.org/10.1063/1.373792 (9 pages) | Cited 109 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The flowing afterglow of a microwave discharge can be used to efficiently inactivate bacterial spores. We have conducted a parametric study of the operating conditions of such a system, which shows that the species participating in the killing of spores are oxygen atoms and ultraviolet (UV) photons. The oxygen atoms and the excited atoms and molecules emitting the photons being carried by the flowing afterglow can be made available throughout the sterilization chamber. Typical operating conditions are: gas mixture 2%O2/98%N2, pressure range 1–7 Torr and gas flow 0.5–3 slm. Total inactivation of 106 B. subtilis spores is achieved within 40 min with 100 W absorbed microwave power, at afterglow gas temperatures not exceeding 50 °C, a feature of interest for heat sensitive medical devices. The present scheme depends on the gas flow reaching all parts of the objects to be sterilized and on the short-lived active species being transported there sufficiently rapid. Under our operating conditions, it is the UV emission intensity that sets the sterilization time as there are always more than sufficient oxygen atoms available for the process. © 2000 American Institute of Physics.
Show PACS
87.80.-y Biophysical techniques (research methods)
52.75.-d Plasma devices
87.53.-j Effects of ionizing radiation on biological systems
52.80.Pi High-frequency and RF discharges
52.80.Hc Glow; corona
Return to All Sections
Close

Google Calendar

ADVERTISEMENT

Go to AIP Home   © AIP Publishing LLC
close