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1.
Nanoscale effects in focused ion beam processing 总被引:3,自引:0,他引:3
Focused ion beams with diameters of 8 to 50 nm are used for material processing in the nanoscale regime. In this paper, effects
of the ion beam–solid interaction determining the formation of small structures by ion-beam sputtering and chemically assisted
material deposition and etching are investigated. In the case of decreasing feature size, angle-dependent sputtering, a non-constant
sputter rate, and scattered ions play an important role. The impact on side-wall angle, aspect ratio, and shape of the bottom
of the etched structures is discussed. In beam tail regions, these effects will be especially pronounced, leading to material
swelling instead of material removal. Ion beam assisted etching and deposition will face additional effects. For small structures,
gas depletion becomes a significant drawback. The impact on gas depletion and the competition with sputtering are discussed.
Received: 21 August 2002 / Accepted: 21 August 2002 / Published online: 12 February 2003
RID="*"
ID="*"Corresponding author. Fax: +49-9131/761360, E-mail: frey@iis-b.fhg.de 相似文献
2.
Transient effects on diffusion and activation during post-implantation anneals are a major obstacle for the further miniaturization
of ultra-large-scale integrated semiconductor devices. The article reviews recent developments in the simulation of such phenomena
with particular emphasis on models for the kinetics of self-interstitial agglomerates and boron–interstitial clusters.
Received: 21 August 2002 / Accepted: 21 August 2002 / Published online: 12 February 2003
RID="*"
ID="*"Corresponding author. Fax: +49-9131/761-212, E-mail: pichler@iis-bfhg.de 相似文献
3.
Crystal structure, morphology, depth profile of elements and mid-infrared optical constants of ‘mild’ lead telluride film 总被引:1,自引:0,他引:1
B. Li S. Zhang F. Zhang L. Zeng 《Applied Physics A: Materials Science & Processing》2003,76(6):965-968
The characterizations of a so-called ‘mild’ PbTe layer thermal-evaporated from an excess of Te (<1 mol.%) evaporable materials
are reported. The results reveal that the film obtained is polycrystalline and has a single-phase NaCl-type PbTe crystal structure.
It is also demonstrated that the film has a homogeneous surface morphology and a high degree of homogeneous distribution of
Te-rich components along the layer. The study of mid-infrared optical constants of a surface-polished film indicates that
the influence of surface scattering on optical properties is very small.
Received: 3 July 2002 / Accepted: 7 August 2002 / Published online: 4 December 2002
RID="*"
ID="*"Corresponding author. Fax: +86-21/6516-9946, E-mail: lbincome@yahoo.com 相似文献
4.
Crunteanu A. Jänchen G. Hoffmann P. Pollnau M. Buchal C. Petraru A. Eason R.W. Shepherd D.P. 《Applied Physics A: Materials Science & Processing》2003,76(7):1109-1112
We present a method for the selective two- and three-dimensional patterning of sapphire using light ion-beam implantation
to generate severe lattice damage to depths exceeding 1 μm and subsequent selective wet chemical etching of the damaged regions
by hot H3PO4. C-cut sapphire crystals were implanted through contact masks using ion fluences of 1×1016 to 5×1017 He+/cm2 and energies up to 400 keV. The etching process is characterized by a high selectivity and a rate of approximately 19 nm/min.
Whereas an implantation that produces a continuously damaged pathway results in complete etching from the surface, sole in-depth
implantation using only high-energy ions leads to under-etching of the crystalline surface layer. By a combination of these
processes we have fabricated three-dimensional structures such as channels and bridges in sapphire.
Received: 14 October 2002 / Accepted: 15 October 2002 / Published online: 26 February 2003
RID="*"
ID="*"Corresponding author. Fax +41-21/693-3701, E-mail: aurelian.crunteanustanescu@epfl.ch 相似文献
5.
Rapid formaldehyde monitoring in ambient air by means of mid-infrared cavity leak-out spectroscopy 总被引:1,自引:0,他引:1
H. Dahnke G. von Basum K. Kleinermanns P. Hering M. Mürtz 《Applied physics. B, Lasers and optics》2002,75(2-3):311-316
We report the spectroscopic detection of formaldehyde in ambient air using cavity leak-out spectroscopy, a cw variant of cavity
ring-down spectroscopy. This technique proved to be suitable for a real-time quantitative analysis of polluted air without
any preprocessing of the air sample. Using a tunable CO-overtone sideband laser for the λ=3 μm spectral region and a ring-down
cell with R=99.95% mirrors, we achieved a detection limit of 2 parts per billion formaldehyde in ambient air, corresponding
to a minimum detectable absorption coefficient of 7×10-9/cm (sampling time: 2 s). Calibration problems arising from the polarity of the molecule and due to HITRAN database uncertainties
are discussed.
Received: 28 March 2002 / Revised version: 7 June 2002 / Published online: 21 August 2002
RID="*"
ID="*"Corresponding author. Fax: +49-211/811-3121, E-mail: muertz@uni-duesseldorf.de 相似文献
6.
It is shown theoretically that electromagnetically induced transparency (EIT) due to strong exciton–phonon coupling can occur
in strongly coupled exciton–phonon systems such as polymers and organic semiconductors and lead to ultra-slow light effects.
The results indicate that the strong coupling of excitons and phonons is important, but the exciton– exciton interaction plays
a small role in the generation of the EIT. Numerical results for polydiacetylene–toluene sulfonate are also presented. This
EIT in a solid-state medium might be utilized for efficient multiwave mixing and quantum nondemolition measurements, as well
as for novel acousto-optical devices.
Received: 21 August 2002 / Published online: 20 December 2002
RID="*"
ID="*"Corresponding author. E-mail: zhukadi@yahoo.com 相似文献
7.
V. Shutthanandan J. Zhang P. Ray 《Applied Physics A: Materials Science & Processing》2003,76(7):1093-1097
Silver, copper, and boron (from a boron nitride target) were sputtered with xenon ions. The isotopic composition of secondary
ions of silver was measured at ion energies ranging from 300 eV to 3 keV and, for copper and boron, at 2.0, 2.5, and 3.0 keV.
An ion gun was used to generate the ion beam. The secondary ions were detected at a small emission angle by a quadrupole mass
spectrometer. The secondary-ion flux of silver was found to be enriched in heavy isotopes at lower incident-ion energies.
The heavy-isotope enrichment was observed to decrease with increasing primary-ion energy. Beyond 500 eV, light isotopes of
silver were sputtered preferentially with the enrichment increasing to a constant value of 1.018. The sputtered flux of copper
and boron also indicated constant enrichments (1.008 and 1.281 for copper and boron respectively) in light isotopes at high
ion energies.
Received: 2 August 2002 / Accepted 9 August 2002: / Published online: 4 December 2002
RID="*"
ID="*"Present address: Pacific Northwest National Laboratory, Richland, WA 99 352, USA
RID="**"
ID="**"Present address: Philips Display Components Company, Ottawa, OH 45 875 USA
RID="***"
ID="***"Corresponding author. Fax: +1-334/727-8090, E-mail: pkray@tusk.edu 相似文献
8.
E. Majkova S. Luby R. Senderak Y. Chushkin M. Jergel I. Zergioti D. Papazoglou A. Manousaki C. Fotakis 《Applied Physics A: Materials Science & Processing》2003,76(5):763-766
The sub-picosecond laser microstructuring of multilayer gratings is presented in this paper. A micromachining system operating
with a 0.5 ps KrF laser at 248 nm was used to etch grating structures with a groove width of 1–2 μm in Mo/Si and Si/Mo multilayers.
Atomic force microscopy, scanning electron microscopy and X-ray reflectivity were used to characterize the microetched patterns.
The ω-scans around the 1st Bragg maximum show symmetric satellites up to 3rd order, with positions corresponding to the grating
period. The use of sub-picosecond laser pulses minimizes the thermally affected zone and enhances the quality of the etched
features. Short pulse laser processing is advantageous for the fabrication of high spatial resolution microstructures required
in X-ray optics.
Received: 21 May 2002 / Accepted: 19 August 2002 / Published online: 15 January 2003
RID="*"
ID="*"Corresponding author. Email: dpapa@iesl.forth.gr 相似文献
9.
M. Takai W. Jarupoonphol C. Ochiai O. Yavas Y.K. Park 《Applied Physics A: Materials Science & Processing》2003,76(7):1007-1012
Localized physical and chemical reactions induced by focused ion and electron beams, i.e. dual beams, have been used to fabricate
field emitters (FEs) and their arrays, field-emitter arrays (FEAs), without masking and annealing processes. Issues arising
from beam processing such as beam-induced damage and contamination were eliminated to provide FEAs with low leakage current.
Quick prototyping and repairing processes of FEs and FEAs using dual-beam processing have been demonstrated.
Nb- or Au-gated Pt FEAs have been fabricated using dual beams. The fabricated FEAs showed a turn-on voltage of 40 V for field
emission with a typical emission current of about 1 μA/tip.
Received: 21 August 2002 / Accepted: 21 August 2002 / Published online: 12 February 2003
RID="*"
ID="*"Corresponding author. Fax: +81-6/6850-6662, E-mail: takai@rcem.osaka-u.ac.jp 相似文献
10.
E.C. Richard K.K. Kelly R.H. Winkler R. Wilson T.L. Thompson R.J. McLaughlin A.L. Schmeltekopf A.F. Tuck 《Applied physics. B, Lasers and optics》2002,75(2-3):183-194
We describe a near-infrared in situ tunable diode laser spectrometer developed for atmospheric measurements of CH4 in the upper troposphere and lower stratosphere (UT/LS). The instrument is designed to provide fast-response (0.5–1 Hz) measurements
and operate autonomously on the NASA WB-57F high-altitude aircraft. A single-mode InGaAsP distributed feedback laser diode
operating at 1.6537 μm scans continuously over the R(3) rotation–vibration transition in the 2ν3 band. We use a direct absorption technique incorporating a custom-designed long path length (252 m) low-volume (3.6 L) astigmatic
Herriott cell. The present detection sensitivity is 5×1010 molecules cm-3, corresponding to ∼20 ppbv in the UT/LS, with the main limit to instrument precision being background optical interference
fringes. In-flight performance is demonstrated by presentation of recent data.
Received: 25 January 2002 / Revised version: 5 April 2002 / Published online: 21 August 2002
RID="*"
ID="*"Corresponding author. Fax: +1-303/497-5373, E-mail: richard@al.noaa.gov 相似文献
11.
J. Fortágh H. Ott S. Kraft A. Günther C. Zimmermann 《Applied physics. B, Lasers and optics》2003,76(2):157-163
In this article, we describe an experimental system for generating Bose–Einstein condensates and controlling the shape and
motion of a condensate by using miniaturised magnetic potentials. In particular, we describe the magnetic trap setup, the
vacuum system, the use of dispenser sources for loading a high number of atoms into the magneto-optical trap, the magnetic
transfer of atoms into the microtrap, and the experimental cycle for generating Bose–Einstein condensates. We present first
results on outcoupling of condensates into a magnetic waveguide and discuss influences of the trap surface on the ultra-cold
ensembles.
Received: 21 August 2002 / Revised version: 10 December 2002 / Published online: 26 February 2003
RID="*"
ID="*"Corresponding author. Fax: +49-7071/295-829, E-mail: fortagh@pit.uni-tuebingen.de 相似文献
12.
Z.J. Li H.J. Li X.L. Chen A.L. Meng K.Z. Li Y.P. Xu L. Dai 《Applied Physics A: Materials Science & Processing》2003,76(4):637-640
Large quantities of high-purity crystalline β-SiC nanowires have been synthesized at relatively low temperature via a new
simple method, the chemical-vapor-reaction approach, in a home-made graphite reaction cell. A mixture of milled Si and SiC
powders and C3H6 were employed as the starting materials. The results show that the nanowires with diameters of about 10–35 nm are single
crystalline β-SiCwithout any wrapping of amorphous material, and the nanowire axes lie along the 〈111〉 direction. Some unique
properties are found in the Raman scattering from the β-SiC nanowires, which are different from previous observations of β-SiC
materials. A possible growth mechanism for the β-SiC nanowires is proposed.
Received: 27 August 2002 / Accepted: 28 August 2002 / Published online: 4 December 2002
RID="*"
ID="*"Corresponding author. Fax: +86-29/8491-000, E-mail: zjli-sohu@sohu.com 相似文献
13.
The progress in the development of a sensor for the detection of trace air constituents to monitor spacecraft air quality
is reported. A continuous-wave (cw), external-cavity tunable diode laser centered at 1.55 μm is used to pump an optical cavity
absorption cell in cw-cavity ringdown spectroscopy (cw-CRDS). Preliminary results are presented that demonstrate the sensitivity,
selectivity and reproducibility of this method. Detection limits of 2.0 ppm for CO, 2.5 ppm for CO2, 1.8 ppm for H2O, 19.4 ppb for NH3, 7.9 ppb for HCN and 4.0 ppb for C2H2 are calculated.
Received: 3 April 2002 / Revised version: 3 June 2002 / Published online: 21 August 2002
RID="*"
ID="*"Corresponding author. Fax: +1-202/994-5873, E-mail: Houston@gwu.edu 相似文献
14.
A portable modular gas sensor for measuring the 13C/12C isotopic ratio in CO2 with a precision of 0.8‰(±1σ) was developed for volcanic gas emission studies. This sensor employed a difference frequency generation (DFG)-based spectroscopic
source operating at 4.35 μm (∼2300 cm-1) in combination with a dual-chamber gas absorption cell. Direct absorption spectroscopy using this specially designed cell
permitted rapid comparisons of isotopic ratios of a gas sample and a reference standard for appropriately selected CO2 absorption lines. Special attention was given to minimizing undesirable precision degrading effects, in particular temperature
and pressure fluctuations.
Received: 16 April 2002 / Revised version: 28 May 2002 / Published online: 21 August 2002
RID="*"
ID="*"Corresponding author. Fax: +1-713/5245237, E-mail: fkt@rice.edu 相似文献
15.
M.B. Pushkarsky M.E. Webber O. Baghdassarian L.R. Narasimhan C.K.N. Patel 《Applied physics. B, Lasers and optics》2002,75(2-3):391-396
An industrial trace-ammonia sensor based on photoacoustic spectroscopy and CO2 lasers has been developed for measuring ammonia with a 1σ detection limit of 220 parts-per-trillion (ppt) in an integration
time of 30 s. The instrument response time for measuring ammonia was 200 s, limited by adsorption effects due to the polar
nature of ammonia. The minimum detectable fractional absorbance was 2.0×10-7, and the minimum normalized detectable absorption coefficient for this system was 2.4×10-7 W cm-1/z. The 9R(30) transition of the CO2 laser at 9.22 μm with 2 W of output power was used to probe the strong sR(5,K) multiplet of ammonia at the same wavelength. This sensor was demonstrated with an optically multiplexed configuration
for simultaneous measurement in four cells.
Received: 3 April 2002 / Revised version: 31 May 2002 / Published online: 21 August 2002
RID="*"
ID="*"Corresponding author. Fax: +1-310/458-0171, E-mail: webber@pranalytica.com 相似文献
16.
J. Botero M.A. Cirone J.P. Dahl F. Straub W.P. Schleich 《Applied physics. B, Lasers and optics》2003,76(2):129-133
We express the commutation relation between the operators of the momentum and the radial unit vectors in D dimensions in differential
and integral form. We connect this commutator with the quantum fictitious potential emerging in the radial Schr?dinger equation
of an s-wave.
Received: 6 August 2002 / Revised version: 30 October 2002 / Published online: 26 February 2003
RID="*"
ID="*"Corresponding author. Fax: +49-731/502-3086, E-mail: markus.cirone@physik.uni-ulm.de 相似文献
17.
Group-IV nanocluster formation by ion-beam synthesis 总被引:1,自引:0,他引:1
W. Skorupa L. Rebohle T. Gebel 《Applied Physics A: Materials Science & Processing》2003,76(7):1049-1059
A short review of our investigations devoted to the use of ion-beam-synthesized nanoclusters for silicon-based light emission
and nonvolatile memory effects is presented. Blue-violet light emission is demonstrated based on Ge-implanted silicon dioxide
layers thermally grown on silicon substrates. This version of silicon-based light emission relies on Ge-related defects in
the amorphous ≡Si–O–Si≡ network. The photoluminescence and electroluminescence are excited by a singlet S0–S1 transition of a neutral oxygen vacancy and by electron injection from the silicon substrate into the silicon dioxide layer,
respectively. Whereas the photoluminescence excitation is a well-known mechanism, for the case of electroluminescence an interpretation
was performed for the first time in the course of our studies. It was found that the most probable way to excite luminescence
centers is the impact excitation by hot electrons. Whereas the injection is explained by trap-assisted tunneling of electrons
from the substrate into the oxide, the electrons will be transported via traps or in the SiO2 conduction band. The application of the silicon-based light-emitting devices for an integrated optocoupler arrangement is
described. Another application of nanoclusters is based on the investigation of thin Si-implanted silicon dioxide layers for
nonvolatile memory devices. First promising results demonstrate that the observed programming window can reach several volts
and the devices exhibit excellent retention behavior. A 256 K-nv-SRAM is demonstrated showing a programming window of >1 V
for write pulses of 12 V/8 ms.
Received: 21 August 2002 / Accepted: 21 August 2002 / Published online: 12 February 2003
RID="*"
ID="*"Corresponding author. Fax: +49-351/260-3411, E-mail: w.skorupa@fz-rossendorf.de 相似文献
18.
Kosterev AA Curl RF Tittel FK Rochat M Beck M Hofstetter D Faist J 《Applied physics. B, Lasers and optics》2002,75(2-3):351-357
Pulsed thermoelectrically cooled QC-DFB lasers operating at 15.6 μm were characterized for spectroscopic gas sensing applications.
A new method for wavelength scanning based on repetition rate modulation was developed. A non-wavelength-selective pyroelectric
detector was incorporated in the sensor configuration giving the advantage of room-temperature operation and low cost. Absorption
lines of CO2 and H2O were observed in ambient air, providing information about the concentration of these species.
Received: 29 April 2002 / Published online: 21 August 2002
RID="*"
ID="*"Corresponding author. Fax: +1-713/348-5686, E-mail: akoster@rice.edu 相似文献
19.
Spectroscopic sensing of gases can be performed with high sensitivity and photometric precision by cavity ringdown (CRD) absorption
spectroscopy. Our cavity ringdown spectrometer incorporates continuous-wave (cw) tunable diode lasers, fibre-optic coupling
and standard photonics and optical telecommunications components. It comprises a rapidly swept optical cavity in a single-ended
optical heterodyne transmitter–receiver configuration, enabling optical absorption of gases to be recorded either as single-frequency
scanned spectra or as simultaneous, multi-wavelength tailored spectra. By measuring weak near-infrared rovibrational spectra
of carbon dioxide gas (CO2), with high resolution in the vicinity of 1.53 μm, we have realised a noise-limited absorption sensitivity of 2.5×10-9 cm-1 Hz-1/2. Analytical sensitivity limits (both actual and projected) and prospective gas-diagnostic applications are discussed. Our
approach to cw-CRD spectroscopy offers high performance in a relatively simple, low-cost, compact instrument that is amenable
to chemical analysis of trace gases in medical, agricultural, industrial and environmental situations.
Received: 16 May 2002 / Revised version: 3 June 2002 / Published online: 21 August 2002
RID="*"
ID="*"Corresponding author. Fax: +61-2/9850-8313, E-mail: brian.orr@mq.edu.au 相似文献
20.
H.R. Zeng G.R. Li Q.R. Yin Z.K. Xu 《Applied Physics A: Materials Science & Processing》2003,76(3):401-404
Pb(Zr,Ti)O3 (PZT) ferroelectric thin film was prepared by the sol-gel technique and crystallized with a (111) preferred orientation.
The domain structure and polarization reversal behavior were investigated by using scanning force microscopy (SFM) piezoresponse
mode at the nanometer scale. A step structure of approximately 30 nm in width was directly observed, which was formed during
the polarization reversal process. The presence of the step structure reveals that the forward domain-growth mechanism is
the dominant domain-switching process in our PZT thin films.
Received: 6 August 2002 / Accepted: 9 August 2002 / Published online: 28 October 2002
RID="*"
ID="*"Corresponding author. Fax: +86-21/5241-3122, E-mail: huarongzeng@163.net 相似文献