共查询到20条相似文献,搜索用时 15 毫秒
1.
Nusrat Lubna Gregory AunerRahul Patwa Hans HerfurthGolam Newaz 《Applied Surface Science》2011,257(10):4749-4753
Thin film materials are widely used in the fabrication of semiconductor microelectronic devices. In thin film deposition, cleanliness of substrate surface have become critically important as over 50% of yield losses in integrated circuit fabrication are caused by microcontamination [1]. There are many wafer cleaning techniques. The most successful approach for silicon wafer cleaning technique is RCA clean [2]. But for glass substrate it is still not known which procedure of cleaning is the best. This paper provides an understanding of the right way of glass wafer cleaning method, with a focus towards identifying good bond strength. Two wafer cleaning techniques have been used for cleaning glass substrates in the context of laser micro-joining of dissimilar substrates. First cleaning procedure involves two steps, first cleaning in acetone solution and then in DI water solution. After each step dried with N2. Second cleaning procedure involves four steps, first cleaning with 1% Alconox solution, second in DI water, third in acetone solution and finally in a methanol solution and dried with N2 after each step. Deposition of Ti thin film on top of these two types of substrate using DC magnetron sputtering method also showed better adhesion of Ti film on glass for the second type of cleaning method. Scanning electron microscopy (SEM) analyses of the lap shear tested failed surfaces for these two kinds of samples revealed strong bond for samples prepared by second cleaning method compared to first cleaning method. Characterization of these two sets of samples using X-ray photoelectron spectroscopy (XPS) has shown excellent contamination removal for the second cleaning method. This modification is believed to be due to reduction of carbon contamination. 相似文献
2.
M. Temporal B. Canaud 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2011,65(3):447-451
Illumination uniformity of a spherical capsule directly driven by laser beams has been
assessed numerically. Laser facilities characterized by
N
D
= 12, 20, 24, 32, 48 and 60 directions
of irradiation with associated a single laser beam or a bundle of
N
B
laser beams have been considered. The
laser beam intensity profile is assumed super-Gaussian and the calculations take into
account beam imperfections as power imbalance and pointing errors. The optimum laser
intensity profile, which minimizes the root-mean-square deviation of the capsule
illumination, depends on the values of the beam imperfections. Assuming that the
N
B
beams are statistically independents is
found that they provide a stochastic homogenization of the laser intensity associated to
the whole bundle, reducing the errors associated to the whole bundle by the
factor
\hbox{1/NB1/21/N_{B}^{1{/}2}}
1
/
N
B
1
/
2
,
which in turn improves the illumination uniformity of the capsule. Moreover, it is found
that the uniformity of the irradiation is almost the same for all facilities and only
depends on the total number of laser beams N
tot
= N
D
× N
B
. 相似文献
3.
A. N. Panchenko A. I. Suslov V. F. Tarasenko I. N. Konovalov A. E. Tel’minov 《Physics of Wave Phenomena》2009,17(4):251-276
The advantages of inductive energy storage (IES) generators for increasing the pulse energy, power, and duration for nitrogen
laser pumped by self-sustained transverse discharge have been experimentally demonstrated. A theoretical model is developed
and the operation of IES-pumped laser on nitrogen-electronegative gas mixtures is numerically simulated. It is shown experimentally
and theoretically that, adding electronegative gases, one can control the pulse shape of lasing on the C3II
u
-B3II
g
transition in nitrogen. The increase in the electric field strength in the laser gap in N2-NF3 and N2-SF6 mixtures produced 337.1-nm laser pulses consisting of two spaced peaks and 40–50-ns pulses close to rectangular. The increase
in the laser active volume to 6 l (discharge cross section to 6×10 cm2) in N2–SF6 mixtures made it possible to obtain the maximum output energy (Q=110 mJ) and UV power (P
las =6 MW). In N2-NF3 mixtures, the laser pulse duration was up to ∼100 ns with an energy up to Q=30 mJ. 相似文献
4.
采用溶胶-凝胶法合成了半导体PbS量子点掺杂的Na2O-B2O3-SiO2玻璃,研究了不同热处理工艺对玻璃结构的影响,利用多种表征手段研究了量子点掺杂玻璃中的微晶结构及其光学性能.孔径分析结果表明随着热处理温度的升高玻璃内部孔径不断减小,最终孔结构几乎完全消失;红外光谱分析表明玻璃网络结构在较低温度下己经形成,随温度的升高不断密实化; X射线光电子能谱证明了玻璃中存在PbS,高分辨透射电镜表征了玻璃基质中掺杂的微晶结构是PbS,统计计算表明,玻璃中微晶的平均粒径尺寸为3.5nm;吸收光谱分析发现,微晶掺杂玻璃的吸收边界较PbS的块体材料发生了明显的蓝移,产生了量子尺寸效应;通过Z扫描技术测得其非线性折射率γ为-2.03×10-14cm2/GW.
关键词:
PbS量子点
半导体
非线性光学效应
溶胶-凝胶法 相似文献
5.
S. Pleasants B.S. Luk’yanchuk D.M. Kane 《Applied Physics A: Materials Science & Processing》2004,79(4-6):1595-1598
A three-dimensional model for laser cleaning of spherical, transparent particles on low-absorbing substrates has been developed. It takes into account near-field focussing of the laser radiation by the particles. The intensity distribution under a particle was found using Mie theory together with the geometrical optics approximation. This permits the estimation of the beam width at the substrate surface and the focal distance of the radiation coming from the spherical particle. These parameters are used to find the distribution of intensity within the low-absorbing substrate from the formula for a focussed Gaussian beam. This is in contrast with most other models of laser cleaning, which assume that all absorption occurs at the surface of the substrate. The energy criterion was used to calculate the threshold fluence. The model predicts threshold fluences of the order of 103 J/cm2 for silica spheres having a diameter of the order of a micron on silica substrates, assuming adhesion by van der Waals force. As this is well above the damage threshold for silica, it effectively predicts that laser cleaning of silica spheres from silica will be impossible. For glass slides the threshold fluence is predicted to be a factor of 10-4 times smaller than that for silica slides (about 0.1 J/cm2). This is due to the much higher absorption of glass compared to that of silica at 248 nm. PACS 42.62.Cf; 81.65.Cf 相似文献
6.
用激光清洗金膜表面硅油污染物 总被引:2,自引:0,他引:2
采用CO2激光对镀金K9玻璃表面的二甲基硅油污染物进行清洗,在激光器单点作用模式下,分别研究了激光功率和作用时间对清洗效果的影响;并研究了连续扫描工作模式下的激光清洗效果。采用光学显微镜和傅里叶变换红外光谱仪表征激光清洗效果,研究结果表明:通过良好的控制激光参数,采用CO2激光清洗二甲基硅油具有明显的效果;此种非接触式清洗方式可确保K9玻璃表面的金膜完好无损。采用有限元分析软件模拟计算了激光功率和作用时间对清洗过程中温度的影响,计算结果与实验结果规律一致。 相似文献
7.
The rovibrational spectra of four isotopomers of the Kr–N2O van der Waals complex, namely 82Kr–N2O, 83Kr–N2O, 84Kr–N2O and 86Kr–N2O, were measured in the v 1 vibrational band region of the N2O monomer (~1285?cm?1) using a tunable diode laser spectrometer to probe a pulsed supersonic slit jet. Rotational constants for both ground and excited vibrational states of these four isotopomers were accurately determined. The band-origin of Kr–N2O was observed to shift by +0.1065?cm?1 from that of the monomer. The band-origin shifts of Rg–N2O (Rg?=?Ne, Ar, Kr) in the v 1 vibrational band region could also be well explained by the model based on a Buckingham intermolecular potential [W.A. Herrebout, H.-B. Qian, H. Yamaguchi and B.J. Howard, J. Mol. Spectrosc. 189, 235 (1998)]. But the band-origin shift of He–N2O was found to deviate significantly from this model. The possible reason is discussed and the band-origin shift of Xe–N2O predicted. 相似文献
8.
In the high power laser facility, surface contaminations on the optics will worsen the laser beam quality and damage the optics. Particle and grease contaminations are two of the usual contaminations on the surface of optics. In this work, the 1064-nm laser induced plasma shockwave cleaning is utilized to remove SiO2 particle contaminations on the K9 glass surface. The results indicate the removal ratio can reach above 95%. The effects of parameters (particle position, laser gap distance and laser energy) on the cleaning efficiency have been studied in the case of single pulse laser cleaning. In addition, CO2 laser (10.6 μm) is utilized to remove the dimethylsilicone oil contaminations on the gold-coated K9 glass surface. The results show that CO2 laser can effectively remove the dimethylsilicone oil by properly controlling the laser parameters. The cleaned area increases with the increased laser power or irradiation time when the other parameters are constant. 相似文献
9.
Optical Kerr nonlinearity (n2) in n-type indium tin oxide (ITO) films coated on glass substrates has been measured using Z-scans with 200-fs laser pulses
at wavelengths ranging from 720 to 780 nm. The magnitudes of the measured nonlinearity in the ITO films were found to be dependent
on the carrier concentration with a maximum n2-value of 4.1×10-5 cm2/GW at 720-nm wavelength and an electron density of Nd=5.8×1020 cm-3. The Kerr nonlinearity was also observed to be varied with the laser wavelength. By employing a femtosecond time-resolved
optical Kerr effect (OKE) technique, the relaxation time of OKE in the ITO films is determined to be ∼1 ps. These findings
suggest that the Kerr nonlinearity in ITO can be tailored by controlling the carrier concentration, which should be highly
desirable in optoelectronic devices for ultrafast all-optical switching.
PACS 42.65.An; 42.65.Hw; 78.40.Fy 相似文献
10.
Thermal lensing has been studied by a probe beam technique in flashlamp-pumped Nd:KGdW laser rods with rod axes positioned
in the N
p–N
g plane and making different angles with the N
g optical indicatrix axis. It was found that the orientation of principal meridional planes of the astigmatic thermal lens
in Nd:KGdW corresponds to the directions with maximum and minimum values of thermal-expansion coefficient in the plane perpendicular
to the rod axis. The athermal Nd:KGdW laser crystal orientation defined as orientation with weak positive near spherical thermal
lens has been determined to make an angle of 30○–40○ with the N
g axis for light polarization E∥N
m. 相似文献
11.
New values of a number of kinetic constants of processes proceeding in oxygen-iodine laser media are presented. The total
probabilities of formation of I2(X, 15 ≤ v ≤ 24) and I2(X, 25 ≤ v ≤ 47) molecules in the course of quenching of I* atoms by I2(X) are found to be 0.9 and 0.1, respectively. The quantum yield of singlet oxygen in the reaction O(1
D) + N2O → N2 + O2(a
1Δ) is close to 100%. The quenching rate constants of I2(A’) by O2, H2O, CO2, I2, and Ar and of I(2
P
1/2) by O(3
P), O3, NO2, N2O4, and N2O are presented. 相似文献
12.
Optical emission spectroscopy experiments are carried out by recording the radiation from the γ transitions of nitrogen monoxide in an air inductively coupled plasma in interaction with a water-cooled metallic flat plate
at moderate pressure. The calibrated results allow to derive the vibrational and rotational temperatures of the NO(A
2
Σ
+) excited state as well as its densities in the free jet and within the boundary layer by comparison with calculated spectra.
Those results are compared with previous ones concerning temperatures and densities of the ground states of the majority species
(N2, O2 and NO) that were obtained by laser techniques. As for the NO(X
2
Π) ground state, vibration and rotation of the excited state are found out of equilibrium. The NO(A
2
Σ
+) excited state is found to be populated by an energy transfer from the metastable N2(
A3\varSigma +uA^{3}\varSigma ^{+}_{u}). The steady state of the plasma allows using this property to derive N2(
A3\varSigma +uA^{3}\varSigma ^{+}_{u}) densities and N2 electronic excitation temperatures. Close to the wall, a production of excited NO by a catalytic process is also considered
involving N2(
A3\varSigma +uA^{3}\varSigma ^{+}_{u}) as source of adsorbed atoms. The present results confirm that the kinetic temperature cannot be compared to the rotational
temperature derived from optical emission spectroscopy in such plasma conditions. 相似文献
13.
D.F. de Sousa L.A.O. Nunes J.H. Rohling M.L. Baesso 《Applied physics. B, Lasers and optics》2003,77(1):59-63
Laser emission at 1077 nm (4F3/24I11/2) was demonstrated in Nd3+-doped low silica content calcium aluminosilicate (LSCA) glass under 810-nm pumping by a Ti:sapphire laser. The slope efficiency of the laser emission was found to be 34% with a 20-mW threshold power. The excited-state absorption (ESA) and stimulated emission were measured between 850 and 1520 nm. The results showed two ESA bands from 931 to 1070 nm (4F3/22D3/2,2G9/2,4G11/2,2K15/2) and from 1160 to 1414 nm (4F3/2,4G9/24G7/2,2K13/2). The stimulated emission for the laser transition was found to be 45-nm broad with a peak value of 1.8×10-20 cm2. Thermal and mechanical properties of the LSCA glass were compared to the ED-2 and LHG-8 glasses. While the mechanical properties of the LSCA glass are superior to those of the commercial glasses, its temperature coefficient of optical path length is the highest among the three hosts. PACS 42.60.Pk; 42.70.Ce; 78.66.Jg 相似文献
14.
在神光Ⅱ装置上,用软X射线激光Mach-Zehnder干涉仪诊断了点聚焦CH等离子体电子密度Ne分布,介绍了实验结果. 通过Abel变换进行了密度反演, 给出了Ne的2D分布,测得的最高Ne为3.2×1021cm-3. 通过同1.5维JB19程序以及二维XRL2D程序的模拟结果的比较,发现高密度区,限流因子取0.05的理论结果同实验相符,但是低密度区实验得到的Ne分布下降得更快,而且理论模拟的Ne二维分布同实验结果在细节上有比较大的差别. 粗略的误差分析显示,干涉仪面型误差是实验误差的主要来源.
关键词:
类镍银X射线激光
Mach-Zehnder干涉仪
密度反演
Abel变换 相似文献
15.
A laser shock cleaning is a new dry cleaning methodology for the effective removal of submicron sized particles from solid surfaces. This technique uses a plasma shock wave produced by laser-induced air breakdown, which has applied to remove nano-scale silica particles from silicon wafer surfaces in this work. In order to characterize the laser shock cleaning process, acoustic waves generated during the shock process are measured in real time by a wide-band microphone and analyzed in the change of process parameters such as laser power density and gas species. It was found that the acoustic intensity is closely correlated with the shock wave intensity. From acoustic analysis, it is seen that acoustic intensity became stronger as incident laser power density increased. In addition, Ar gas has been found to be more effective to enhance the acoustic intensity, which allows higher cleaning performance compared with air or N2 gas. 相似文献
16.
研究了Tm3+/Ho3+共掺TeO2-WO3-ZnO玻璃在808 nm激光二极管抽运下的2.0μm发光特性及Tm3+与Ho3+之间的能量传递.应用Judd-Ofelt理论计算了Ho3+在碲酸盐玻璃中的谱线强度参量Ωt (t=2,4,6)、自发辐射概率Ar、辐射寿命τr等.计算了Ho3+的吸收截面σa(λ)和受激发射截面σe(λ).结果表明:碲酸盐玻璃中Tm3+→Ho3+正向能量传递系数大约是Tm3+←Ho3+反向能量传递系数的18倍.Ho3+离子的5I7能级的寿命为3.9ms,2.0μm处的最大发射截面为9.15×10-21cm2.在0.5mol% Tm2O3和0.15mol% Ho2O3共掺的碲酸盐玻璃中能获得2.0μm的最大增益.通过比较氟化物、碲酸盐和镓铋酸盐重金属氧化物等玻璃中Ho3+的量子效率η,σe×τm值和增益系数G(λ)等,发现Tm3+/Ho3+共掺碲酸盐玻璃是一种理想的2.0μm激光器用基质玻璃.
关键词:
2.0μm发光
能量传递
增益
碲酸盐玻璃 相似文献
17.
R. Larciprete E. Borsella P. Cinti 《Applied Physics A: Materials Science & Processing》1996,62(2):103-114
The mechanism of KrF-excimer-laser cleaning of Si(100) surfaces was studied by Auger Electron Spectroscopy (AES) and Low-Energy Electron Diffraction (LEED) spectroscopy. The dependence of the cleaning efficiency on the laser fluence was investigated by using a mildly focused laser beam and carefully measuring the energy density distribution of the laser spot impinging on the sample. These values were compared with the AES spectra measured in different points of the irradiated area and with the morphology observed by optical microscopy. Samples as received from the manufacturer were first investigated. It was found that desorption of weakly bonded organic adsorbates occurs at energy densities as low as 0.3 J/cm2, whereas significant oxide removal takes place only at an energy density above 0.8 J/cm2, which produces damaged surface morphologies. The experimental findings, in agreement with the temperatures calculated for the laser-induced Si heating, indicated that a large fraction of the oxide film is dissolved in the molten silicon, leading to oxygen concentration below the AES detection limit only when the melted depth was of the order of several hundred nanometers. Atomically clean, damage-free Si(100) surfaces were obtained after irradiation of samples pre-etched for 1 min in a HF: H2O (5%) solution, which had only a thin SiO
x
(x < 2) layer and F, C and O containing adsorbed species. Complete contaminant elimination was achieved in this case with 15 pulses at 0.8 J/cm2 without any damaging of the surface. 相似文献
18.
Light pulses of 149 m wavelength and 700 ps duration are generated by non-collinear phase-matched difference frequency mixing of laser pulses at 1053.5 and 1061 nm in a (110) cut GaP crystal. The pump laser pulses are generated in a time-synchronized mode-locked double-frequency Nd:glass laser system consisting of a silicate glass branch and a phosphate glass branch. A photon conversion efficiency of 4 × 10–6 is achieved. The non-linear susceptibility constant of GaP is determined to be d
14 = (10 ± 1) pm V–1. 相似文献
19.
The stimulated emission cross-section σ and fluorescence lifetime for the 1.06 μm emission (4F3/2 →4I1/12) have been measured for a number of Nd-doped tellurite glasses. The measured value of σ ? 9 × 10-20 cm 2 for the tellurite glasses is to be compared with the value of 3.5 × 10-20 cm 2 for the ED-2 glass. Based on the measured spectroscopic parameters, an LED-pumped tellurite glass fiber laser is predicted to perform better than ED-2 glass, both in the longitudinal and transverse pumping configuration. The threshold for side-pumped tellurite glass laser can be comparable or even lower than that in Nd:YAG. 相似文献
20.
The isospin dependence of shell closure phenomena is studied for light neutron-rich nuclei within a microscopic self-consistent
approach using the Gogny force. Introducing configuration mixing, 32Mg is found to be dynamically deformed, although the N = 20 spherical shell closure persists at the mean-field level for all N = 20 isotones. In contrast, the N = 28 spherical shell closure is found to disappear for N - Z≥ 10 whereas deformed shell closures are preserved and lead to shape coexistence in 44
S. Configuration mixing shows that the ground state of this nucleus is triaxially deformed. The first 2+ excitation energy Ex = 1.46 MeV and the reduced transition probability B(E2;0+
gs→ 2+
1)= 420 e
2
fm
4 obtained with our approach are in good agreement with experimental data.
Received: 26 July 2000 / Accepted: 30 August 2000 相似文献