Excimer Laser Etching of Cupric Oxide

1988 ◽  
Vol 100 ◽  
Author(s):  
G. N. A. van Veen ◽  
W. Vrijmoeth ◽  
T. S. Baller ◽  
J. Dieleman
Keyword(s):  
Excimer Laser ◽  
Cupric Oxide ◽  
Laser Pulses ◽  
Laser Etching ◽  
Additional Information ◽  
Higher Power ◽  
Thermal Mechanism ◽  
Power Densities ◽  
Flight Measurements ◽  
Scanning Electron

ABSTRACTPolycrystalline CuO samples are irradiated in UHV by excimer laser pulses at 308nm. Mass spectrometry combined with time-of-flight measurements is used to determine the composition of the desorbing particles and the desorption mechanisms. Additional information is provided by Scanning-Electron-Microscopy of the etched surfaces. At fluences below 1.8 J cm−2 the products Cu, O and O2 are desorbed by a purely thermal mechanism at temperatures up to 6000 K and a copper rich surface mask is formed. At higher power densities an additional ablative contribution is monitored which increases with power density, and much less surface area is covered by a Cu-rich mask.

Angle Resolved Time-of-Flight Measurements of the Excimer Laser Induced Etching of Silicon in a Chlorine Environment

1988 ◽  
Vol 129 ◽  
Author(s):  
T.S. Baller ◽  
J. van Zwol ◽  
S.T. de Zwart ◽  
G.N.A. van Veen ◽  
H. Fell ◽  
...  
Keyword(s):  
Gas Phase ◽  
Excimer Laser ◽  
Time Of Flight ◽  
Laser Pulses ◽  
Angular Distributions ◽  
Desorption Process ◽  
Surface Time ◽  
The Mean ◽  
Laser Induced Etching ◽  
Flight Measurements

ABSTRACTSi (100) samples have been irradiated with excimer laser pulses (λ = 308nm, pulsewidth =28ns) in a low pressure chlorine environment, at a fluence just enough to melt the surface. Time-of-flight spectra of the particles desorbed due to the laser irradiation have been measured as a function of effective chlorine pressure and desorption angle. Maxwell- Boltzmann distributions have been used to fit the measurements. The mean kinetic energy per particle increases with increasing chlorine pressure. Angular distributions of the desorbed particles are found to be cosine like at a chlorine coverage much less than a monolayer and sharply peaked along the surface normal at coverages on the order of a monolayer. Monte-Carlo simulations of the desorption process show that due to collisions between the desorbed particles the change in angular distribution can be explained. The increase in mean energy with increasing chlorine coverage however cannot be explained by gas phase collisions. A possible desorption process is suggested.

Edge Penetration Effects in the Low-Loss Electron Image in the SEM

1988 ◽  
Vol 46 ◽  
pp. 202-203
Author(s):  
Oliver C. Wells
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Beam Energy ◽  
Secondary Electron ◽  
Sharp Edge ◽  
Beam Diameter ◽  
Low Loss ◽  
Additional Information ◽  
Electron Image ◽  
Scanning Electron

The low-loss electron (LLE) image in the scanning electron microscope (SEM) is useful for the study of uncoated photoresist and some other poorly conducting specimens because it is less sensitive to specimen charging than is the secondary electron (SE) image. A second advantage can arise from a significant reduction in the width of the “penetration fringe” close to a sharp edge. Although both of these problems can also be solved by operating with a beam energy of about 1 keV, the LLE image has the advantage that it permits the use of a higher beam energy and therefore (for a given SEM) a smaller beam diameter. It is an additional attraction of the LLE image that it can be obtained simultaneously with the SE image, and this gives additional information in many cases. This paper shows the reduction in penetration effects given by the use of the LLE image.

Shortening of excimer laser pulses with saturable absorbers

1984 ◽  
Vol 52 (3) ◽  
pp. 211-214 ◽  
Author(s):  
Ch.G. Christov ◽  
I.V. Tomov ◽  
I.V. Chaltakov ◽  
V.L. Lyutskanov
Keyword(s):  
Excimer Laser ◽  
Laser Pulses ◽  
Saturable Absorbers

Surface Composition Changes and Ablation Dynamics in Excimer Laser Irradiated CdTe

1990 ◽  
Vol 191 ◽  
Author(s):  
P. D. Brewer ◽  
J. J. Zinck ◽  
G. L. Olson
Keyword(s):  
Laser Ablation ◽  
Excimer Laser ◽  
Surface Composition ◽  
Laser Ablation Process ◽  
Flight Mass Spectrometry ◽  
Rich Condition ◽  
Thermal Mechanism ◽  
Krf Excimer Laser ◽  
Composition Changes ◽  
Cdte Surface

ABSTRACTWe have investigated the dynamics of KrF excimer laser ablation of CdTe and the fluence dependent changes in surface stoichiometry that accompany the laser ablation process. The composition of the CdTe surface was reversibly controlled between stoichiometric and a Te-rich condition by varying the laser fluence over the range from 15–65 mJ/cm2. The primary species ejected from the irradiated surface were Cd atoms and Te2 molecules. Their velocity distributions as measured by time-of-flight mass spectrometry were found to be Maxwellian. From the analysis of the velocity distributions, the preferential desorption of surface atoms, and the reversible nature of the process, we conclude that the desorption is due to a photo-thermal mechanism which mediates the competition between Te2 formation and desorption and the desorption of Cd atoms.

KrF excimer laser etching of diamondlike carbon films

1992 ◽  
Author(s):  
Taras V. Kononenko ◽  
Vitali I. Konov ◽  
Victor G. Ralchenko ◽  
V. E. Strelnitsky
Keyword(s):  
Excimer Laser ◽  
Carbon Films ◽  
Laser Etching ◽  
Diamondlike Carbon ◽  
Krf Excimer Laser

Excimer Laser Interaction with Metals

1992 ◽  
Vol 285 ◽  
Author(s):  
W.W. Duley ◽  
G. Kinsman
Keyword(s):  
Experimental Data ◽  
Laser Radiation ◽  
Excimer Laser ◽  
Metal Surfaces ◽  
Laser Pulses ◽  
Radiative Properties ◽  
Uv Laser ◽  
Laser Interaction ◽  
Excimer Laser Radiation

ABSTRACTExcimer laser radiation may be used to process metal surfaces in a variety of novel ways. The simplest of these involves the use of UV laser pulses for ablation. Ablation occurs as the result of both vaporization and hydrodynamical effects. Experimental data related to these processes will be discussed. In addition, it will be shown how specific irradiation regimes can yield metal surfaces with unique radiative properties.

Surface hardening of SUS304 by irradiation with a KrF excimer laser in SiH4 gas ambient

1990 ◽  
Vol 5 (2) ◽  
pp. 265-270 ◽  
Author(s):  
Koji Sugioka ◽  
Hideo Tashiro ◽  
Koichi Toyoda ◽  
Eiichi Tamura ◽  
Keigo Nagasaka
Keyword(s):  
Excimer Laser ◽  
Surface Hardening ◽  
Continuous Distribution ◽  
Surface Hardness ◽  
Laser Pulses ◽  
High Concentration ◽  
Laser Fluences ◽  
High Adhesion ◽  
Krf Excimer Laser ◽  
Si Films

Surface hardening of SUS304 resulting from the process of doping and deposition of Si by irradiation of a KrF excimer laser beam in a SiH4 gas ambient is investigated, and variations of the surface hardness are examined for different numbers of laser pulses and the laser fluences. The hardening is due to Si incorporation in high concentration. The continuous distribution of Si atoms across the surface layer suggests that a very high adhesion strength of the deposited Si films can be formed. The specific process for surface modification is referred to as laser implant-deposition (LID).

An Investigation of Methane Combustion in a Rectangular Shaped Meso Chamber

2014 ◽  
Author(s):  
Mahbub Ahmed ◽  
Cheng Zhang ◽  
Scott McKay ◽  
Vivek Shirsat ◽  
Jobaidur Khan
Keyword(s):  
Cfd Simulation ◽  
Methane Combustion ◽  
Ansys Fluent ◽  
Flamelet Model ◽  
Power Generators ◽  
Rich Condition ◽  
Higher Power ◽  
Fluent Software ◽  
Finite Volume Approach ◽  
Power Densities

Hydrocarbon-based miniature power generators are promising any many application since hydrocarbon based fuels have higher power densities compared to conventional lithium batteries. A 40mm long meso-combustor of two different configurations, two-inlet and three-inlet, were used to investigate the combustion of methane in the meso-chamber. A non-premixed combustion of methane and oxygen was simulated numerically using a steady laminar flamelet model. The mesh generation and the CFD simulation were performed using ANSYS FLUENT software. A a finite volume approach was used for the simulation. The fuel-oxidizer mixing, thermal behavior and fuel burning efficiency were studied. An adequate mixing that supports the combustion was observed in certain locations. The exhaust gas was analyzed experimentally. The temperature distributions were also observed to predict the flame locations. According to the numerical analysis it was apparent that the flame would be anchored in the well mixed regions of the chamber the flames were found to be attached in two distinct locations. One in the upstream zone and the other one in the downstream zone. Another important finding was that the fuel lean condition produced higher efficiency than the fuel rich condition.

Nano-Structuring with Femtosecond Excimer Laser Pulses

2005 ◽  
pp. 279-283 ◽  
Author(s):  
J.-H. Klein-Wiele ◽  
J. Bekesi ◽  
J. Ihlemann ◽  
P. Simon
Keyword(s):  
Excimer Laser ◽  
Laser Pulses
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