共查询到20条相似文献,搜索用时 12 毫秒
1.
D. Kray A. Fell S. Hopman K. Mayer G. P. Willeke S. W. Glunz 《Applied Physics A: Materials Science & Processing》2008,93(1):99-103
Laser Chemical Processing (LCP) is presented as a novel microstructuring method for multiple applications. Via the combination
of a chemical liquid jet and a laser beam, thermochemical and photochemical reactions can be initiated. Due to the free choice
of the chemistry for the carrier liquid and the laser source, efficient processes can be devised for a large variety of applications.
We present some examples for the microstructuring of silicon with the focus on etching, selective doping of phosphorous and
the combination of etching and doping. 相似文献
2.
Sybille Hopman Kuno Mayer Andreas Fell Matthias Mesec Filip Granek 《Applied Physics A: Materials Science & Processing》2011,102(3):621-627
In this paper results for liquid media are presented, which are used the first time as liquid jet for cutting of silicon with
laser chemical processing (LCP). The liquids contain a perfluoro-carbon compound as solvent and elemental chlorine as etching
agent for silicon. Experiments were performed to investigate its influence on groove form and maximum achieved groove depth.
It is shown that with the addition of low-concentration chlorine, the groove depth can already be significantly increased.
The groove shape could be changed from a V-profile to a U-profile. Furthermore, an about four times greater groove depth was
achieved by applying a saturated chlorine solution compared to groove depths without using chlorine. Finally, a theory is
given and discussed to describe the phenomena observed. 相似文献
3.
We report the experimental results of picosecond pulse laser microstructurlng (pulse duration 35 ps, wavelength 1.06μm, repetition rate 10 Hz) of silicon using the direct focusing technique. Arrays of sharp coldcal spikes located below the initial surface have been formed by cumulative picosecond pulsed laser irradiation of silicon in SF6. Irradiation of silicon surface in air, N2, or vacuum creates ripple-like patterns, but does not create the sharp conical spikes. 相似文献
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ZHANGGuowei SHIWenkang JIXiaojun HANTao 《声学学报:英文版》2004,23(3):251-258
For comprehending the propagation characteristics of surface acoustic waves (SAW) on novel piezoelectric crystal Langatate (LGT), the numerical analysis of the most important propagation characteristics of surface acoustic waves (SAW) on LGT are presented and compared with that of quartz. The results are that the phase velocity on LGT is generally about 1000 m/s slower than that on quartz; there are zero temperature cuts and pure mode directions on LGT; the electromechanical coupling coefficient (K^2) of LGT is larger than that of quartz. The results show that LGT has lower propagation velocity, higher electromechanical coupling coefficient, good temperature stability and other good characteristic. The results also show that there are somewhat deviations with different material constants, especially, the temperature coefficient of frequency. 相似文献
6.
GaN thin films grown on sapphire substrates by metalorganic chemical vapor deposition (MOCVD) are successfully bonded and transferred onto Si receptor substrates using fusion bonding and laser lift-off (LLO) technique. GaN/Al_2O_3 structures are joined to Si substrates by pressure bonding Ti/Au coated GaN surface onto Ti/Au coated Si receptor substrates at the temperature of 400℃. KrF excimer laser with 400-mJ/cm~2 energy density, 248-nm wavelength, and 30-ns pulse width is used to irradiate the wafer through the transparent sapphire substrates and separate GaN films from sapphire. Cross-section scanning electron microscopy (SEM) combined with energy dispersive X-ray spectrometer (EDS) measurements show that Au/Si solid solution is formed during bonding process. Atomic force microscopy (AFM) and photoluminescence (PL) measurements show that the qualities of GaN films on Si substrates degrade little after substrates transfer. 相似文献
7.
TheHardnessPropertiesofCarbonSteelsAfterLaserProcessing¥ZHUZuchang;WANGWeixiang;LIXiuqian;YUShaoluo(ShanghaiUniversityofEngin... 相似文献
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9.
Dong Zhang Yizhen Bai Fuwen Qin Fuchao Jia Jian Wang Jiming Bian 《Applied Physics A: Materials Science & Processing》2011,102(2):353-358
High-quality GaN films are deposited on freestanding thick diamond films by electron cyclotron resonance plasma enhanced metal
organic chemical vapor deposition (ECR-PEMOCVD). The TMGa flux dependent structural, morphological, and electrical characteristics
of GaN films were investigated by x-ray diffraction analysis (XRD), reflection high-energy electron diffraction (RHEED), atomic
force microscopy (AFM) and Hall effect measurement. The results indicate that it is feasible to deposit GaN films on freestanding
thick diamond films under the proper deposition procedures. The high-quality GaN films with small surface roughness of 4.9 nm
and high c-orientation are successfully achieved at the optimized TMGa flux of 0.5 sccm. The GaN/diamond structure has great
potential for the development of SAW devices with high frequencies and low insertion. 相似文献
10.
P. Frank J. Graf F. Lang J. Boneberg P. Leiderer 《Applied Physics A: Materials Science & Processing》2010,101(1):7-11
The ejection dynamics of nanometer-thin fluid isopropanol and solid CO2 films are investigated. The films are deposited on a silicon substrate, which is rapidly heated by a nanosecond laser pulse
(Nd:YAG, 532 nm). A small fraction of material at the interface evaporates and the film on top is ejected as an intact layer.
The kinetic energies of the two different films with thicknesses between 100 nm and 1 μm give an insight into the dynamics
of a flying lamella. 相似文献
11.
GAOZhi SHENYi-Qing FANAn-Fu 《中国物理快报》2004,21(6):1079-1082
A new oxygen-iodine medium gain model is developed to include pumping and deactivation of the upper laserlevels of the iodine atoms, hyperfine and translation relaxation, as well as the flowing effect. The rate equationsfor gain of a supersonic flowing cw oxygen-iodine laser (COIL) are described when the medium is stimulated bya single-mode field. The general solution of the self-consistency integral equation is obtained. The result showsthat the saturation behaviour in low pressure of the COIL differs from both the inhomogeneous and homogeneousbroadening, and exhibits an ‘anomalous‘ saturation phenomenon. 相似文献
12.
Shibkov A. A. Gasanov M. F. Zolotov A. E. Zheltov M. A. Denisov A. A. Kochegarov S. S. 《Physics of the Solid State》2019,61(8):1354-1362
Physics of the Solid State - The effect of surface processing by laser IR radiation on strength and Portevin–Le Chatelier serrated deformation of AlMg6 aluminum–magnesium alloy is... 相似文献
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14.
M. B. Agranat S. I. Ashitkov S. I. Anisimov A. V. Ovchinnikov A. B. Shvartsburg D. S. Sitnikov V. E. Fortov 《Applied Physics A: Materials Science & Processing》2009,94(4):879-887
The experimental study of absorption in silicon in infrared and visible spectral ranges, where the photon energy is less or
more than the bandgap width, is performed by means of the ultrafast interferometry technique. The exactly solvable model in
the electromagnetic of heterogeneous lossy plasma layer was developed. The density of carriers, their frequency of collisions,
absorbing depth of the probing waves, real and imaginary parts of dielectric function of nonuniform layer and their spatial
gradients are determined from the reflectance data by means of this model subject to the pump fluence. The heterogeneity-induced
effects are visualized due to comparison of obtained plasma parameters with those calculated in the framework of homogeneous
plasma model It is shown that in the intensity range near thresholds of melting and ablation the absorption, occurring in
both cases mainly within a thin (∼10 nm) absorbing layer (similarly to metals), is due to free carrier intraband absorption. 相似文献
15.
Seisuke Nakashima Koji Sugioka Katsumi Midorikawa 《Applied Physics A: Materials Science & Processing》2010,101(3):475-481
By using a second harmonic of near infrared femtosecond (fs) laser (λ=387 nm, 150 fs) with high NA objective lens, fabrication resolution has been greatly improved in nano-fabrication of wide
band-gap semiconductor gallium nitride (GaN). We have carried out a wet-chemical-assisted fs laser ablation method, in which
the laser beam is focused onto a single-crystal GaN substrate immersed in a concentrated hydrochloric (HCl) acid solution.
A two-step processing involving irradiation with a fs laser beam in air followed by wet chemical treatment is also performed
for comparison. In the wet-chemical-assisted ablation, theoretical diameters of ablation craters are calculated as a function
of pulse energy by assuming that the reaction is based on two-photon absorption. In lower energy, the calculated curve is
close to the experimental value, while the actual measured diameters in the region of higher energy are larger than calculated
values. In the condition of the highest fabrication resolution, we obtained ablation craters smaller than 200 nm at full width
at half maximum. We have also demonstrated the fabrication of two-dimensional (2D) periodic nanostructures on surface of a
GaN substrate using the second harmonic single fs-laser pulse. Uniform ablation craters with the size as small as 410 nm in
diameter are arranged with a periodicity of 1 μm. Such structures are applicable to 2D photonic crystals which improve the
light extraction efficiency for blue LEDs in the near future. 相似文献
16.
Dong-Jiang Wu Guang-Yi Ma Shuang Liu Xu-Yue Wang Dong-Ming Guo 《Applied Physics A: Materials Science & Processing》2010,101(3):517-521
Based on the requirements for silicon sheets with different thickness in MEMS, and according to the experimental results,
the element of the temperature distribution was investigated by calculation with ANSYS, and the bending mechanism of different
thicknesses of the silicon sheet is proposed. The results showed that the plastic deformation was delayed as the thickness
is increased. The bending angle was bigger with the increment being smaller as the scanning numbers increased, and the biggest
bending angle was obtained finally. 相似文献
17.
The selective ablation of thin (∼100 nm) SiO2 layers from silicon wafers has been investigated by applying ultra-short laser pulses at a wavelength of 800 nm with pulse
durations in the range from 50 to 2000 fs. We found a strong, monotonic decrease of the laser fluence needed for complete
ablation of the dielectric layer with decreasing pulse duration. The threshold fluence for 100% ablation probability decreased
from 750 mJ/cm2 at 2 ps to 480 mJ/cm2 at 50 fs. Significant corruption of the opened Si surface has been observed above ∼1200 mJ/cm2, independent of pulse duration. By a detailed analysis of the experimental series the values for melting and breaking thresholds
are obtained; the physical mechanisms responsible for the significant dependence on the laser pulse duration are discussed. 相似文献
18.
We have demonstrated passive mode-locking in a diode-end-pumped Nd:YV04 laser using two kinds of semiconductor absorbers whose relaxation region comes from Ino.2sGao.75As grown at low temperature (LT) and GaAs/air interface respectively. Mode-locking, using absorbers of the GaAs/air interface relaxation region, has the characteristics of less Q-switching tendency and higher average output power than that using absorbers of LT In0.25Ga0.75As relaxation region, but is not as stable as the latter. 相似文献
19.
The stationary properties of a saturation laser model with cross-correlation between the real and imaginary parts of the quantum
noise are investigated theoretically. Using the Novikov theorem and the Sargent technique, we obtain the analytic expressions
of the stationary probability density distribution, the mean, the variance and the skewness of the saturation laser model.
The cross-correlation coefficient λ and other parameters can make the stationary probability density distribution P
st
(I) generate interesting two-extrema structure, one-extremum structure, or no-extremum structure. It is clearly found that a
first- order-like-transition is induced by the coupling strength |λ| of the complex quantum noise terms in the saturation laser model. When the laser system is operated above the threshold,
the mean 〈I〉 becomes larger and the output of the laser intensity increases; however the coupling strength |λ| attenuates the output of the laser intensity. When the laser is operated near and below the threshold, the mean 〈I〉 becomes smaller, the output of the laser intensity decreases, and |λ| still attenuates the output of the laser intensity. When a periodic signal is added to a saturation laser model with cross-correlation
between quantum noise terms, the interesting stochastic resonance phenomena occur at λ=0. The noise intensity Q decreases the values of the resonance peak, however, the amplitude of the periodic signal B enhances the values of the resonance peak. 相似文献
20.
Comparison of plume expansion in femtosecond laser ablation on oxidized and non-oxidized Sm surfaces
M. Kurata-Nishimura Y. Matsuo T. Kobayashi T. Kato Y. Hayashizaki J. Kawai 《Applied Physics A: Materials Science & Processing》2008,92(4):1047-1050
Time development of Sm+ and Sm ablation plume produced by the femtosecond laser irradiation has been investigated. The two-dimensional spatial profiles
of Sm and Sm+ emitted from oxidized and non-oxidized Sm surface were visualized using a planar laser-induced fluorescence method. It was
observed that the flow velocity of Sm+ is much faster than that of Sm plume in both surfaces. The plumes from the oxidized Sm surface show higher velocity than
that from non-oxidized surface, which is originated by the small electric conductivity at the surface. Expansion property
observed for Sm+ and Sm plume in the oxidized Sm surface ablation implies the formation of the Knundsen layer nearby the surface. Meanwhile,
continuous emission of Sm indicates the large contribution of heating effect to emission process at the non-oxidized surface.
We conclude that the fsLA process strongly depends on the electric property of the ablated surface and the heating effect
contributes to the particle emission process on the conductive material surface. 相似文献