CRACKING AND EXFOLIATION OF TiO2 FILM IRRADIATED WITH EXCIMER LASER

TiO 2 film deposited on glass was irradiated in air with single-shot KrF excimer laser pulse. The surface roughened as the result of the laser ablation. It is further noted that single-pulse irradiation with fluence ranging from 400 to 1200 mJ/cm2 gave rise to protrusion of the irradiated surface above the original surface, which is in contrast to usual expectation that irradiated surface is below the unirradiated surface. The surface protrusion is mainly attributed to the effect of surface tension. At the laser fluence of 1000 mJ/cm2, cracks were formed in the irradiated area and severe film exfoliation was observed at the periphery of the irradiated area due to the release of internal stress. With higher laser fluence above 1000 mJ/cm2, patches of film were observed to peel off within the irradiated areas. Hydrodynamic ablation is proposed to account for film exfoliation. The observed phenomenon is useful for further understanding how TiO 2 film reacts to strong UV laser irradiation.

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Parametric Investigation of Laser-Assisted Direct Imprint (LADI) Technique

Materials Science Forum ◽

10.4028/www.scientific.net/msf.505-507.307 ◽

2006 ◽

Vol 505-507 ◽

pp. 307-312 ◽

Cited By ~ 1

Author(s):

C.Y. Lin ◽

Yung Chun Lee ◽

Fei Bin Hsiao ◽

C.H. Chuang

Keyword(s):

Excimer Laser ◽

Laser Fluence ◽

Promising Technique ◽

New Approach ◽

Heating Source ◽

Excimer Laser Pulse ◽

Machining System ◽

Conventional Photolithography ◽

Silicon Materials ◽

Krf Excimer Laser

Nano-imprinting Lithography (NIL) has been considered as the most promising technique for nano-scaled fabrication and patterning. Recently, a new approach known as Laser-Assisted Direct Imprinting(LADI) has been proposed and demonstrated as an even more efficient way for direct nanofabrication and nanopatterning. In this study, we focused on silicon materials and utilized a single KrF excimer laser pulse (248 nm wavelength and 30 ns pulse duration) as the heating source. Molds of micro-scaled size have been prepared using conventional photolithography techniques. A working platform based on an Excimer Laser Micro-Machining system is constructed for LADI process. The influence of laser fluence and the imprinted pressure on the resulting structures was verifying by varying the laser fluence (1.0 ~ 1.2 J/cm2) and the imprinted load (3 ~ 9kg). The results have shown that the morphology and the imprinted depth were directly related to the laser fluence and the imprinted pressure. Quantitative data are obtained and will be addressed.

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Single pulse vibrational Raman scattering by a broadband KrF excimer laser in a hydrogen–air flame

Applied Optics ◽

10.1364/ao.29.002325 ◽

1990 ◽

Vol 29 (15) ◽

pp. 2325 ◽

Cited By ~ 40

Author(s):

Robert W. Pitz ◽

Joseph A. Wehrmeyer ◽

J. M. Bowling ◽

Tsarng-Sheng Cheng

Keyword(s):

Raman Scattering ◽

Excimer Laser ◽

Single Pulse ◽

Krf Excimer Laser

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Influence of laser fluence and irradiation timing of F 2 laser on ablation properties of fused silica in F 2 -KrF excimer laser multi-wavelength excitation process

Applied Physics A ◽

10.1007/s003390101000 ◽

2001 ◽

Vol 73 (6) ◽

pp. 755-759 ◽

Cited By ~ 21

Author(s):

K. Obata ◽

K. Sugioka ◽

T. Akane ◽

N. Aoki ◽

K. Toyoda ◽

...

Keyword(s):

Excimer Laser ◽

Laser Fluence ◽

Fused Silica ◽

Excitation Process ◽

Multi Wavelength ◽

Krf Excimer Laser

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Femtosecond Pulsed Laser-Induced Micromachining of Difficult-to-Machine Materials: Diamond a Case Study

10.1115/imece2000-1905 ◽

2000 ◽

Author(s):

A. P. Malshe ◽

A. M. Ozkan ◽

T. A. Railkar ◽

K. P. Adhi ◽

W. D. Brown ◽

...

Keyword(s):

Raman Spectroscopy ◽

Excimer Laser ◽

Etching Rate ◽

Polycrystalline Diamond ◽

Single Pulse ◽

Laser Wavelength ◽

Diamond Surface ◽

Single Shot ◽

Micro Machining ◽

3 Dimensional

Abstract Meso and micro scale machining is an important and emerging area of research. Various non-traditional and novel tools are being explored for meso and micro machining of non-silicon materials. In this paper, we report etching, micro machining and related phenomena of commercially available single and polycrystalline diamond using a femtosecond pulsed excimer laser (λ = 248 nm, tp ∼ 380 fs). Surface modifications due to single pulse and multiple pulse irradiation of diamond samples, at different energy densities, have been analyzed using Raman spectroscopy, scanning electron microscopy (SEM) and atomic force microscopy (AFM). Etching rate of single crystal type IIA diamond by femtosecond pulsed excimer laser is also studied. Raman spectroscopy study of the single shot irradiation of diamond with a femto second laser shows the formation of a non-diamond disordered (sp2 bonded) phase on the surface. However, subsequent micro machining of this non-diamond disordered surface, by delivering several shots from the femtosecond laser, results in the removal of the non-diamond disordered layer and the restoration of the diamond surface. It is experimentally shown that the periodicity of the 2-dimensional corrugations written on diamond surface is shorter than the laser wavelength used. 3-dimensional writing on diamond globules during laser etching is also discussed. Further, micro machining of diamond tips is shown to be precise, and without mechanical and chemical damages. Femto second laser is demonstrated as a next-generation tool for mechanical and chemical damage free precision micro machining of the hardest material, diamond.

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Effects of Processing Parameters on KrF Excimer Laser Ablation Deposited ZrO2 Films

MRS Proceedings ◽

10.1557/proc-236-429 ◽

1991 ◽

Vol 236 ◽

Cited By ~ 4

Author(s):

Gary A. Smith ◽

Li-Chyong Chen ◽

Mei-Chen Chuang

Keyword(s):

Laser Ablation ◽

Substrate Temperature ◽

Excimer Laser ◽

Deposition Rate ◽

Oxygen Pressure ◽

Pressure Dependence ◽

Laser Fluence ◽

X Ray ◽

Excimer Laser Ablation ◽

Krf Excimer Laser

AbstractSystematic experiments have been carried out to characterize the yttria containing zirconia thin films on sapphire substrates by 248nm KrF excimer laser ablation. The deposition rate as a function of laser fluence and O2 pressure at room temperature was measured with a quartz crystal microbalance. The results show different threshold fluences for deposition in vacuum vs. oxygen. While the deposition rate increases with increasing fluence at a given oxygen pressure, the rate eventually saturates at a higher laser fluence. At a given fluence, the oxygen pressure dependence of the deposition rate shows a radical reduction when the O2 pressure increases from 10 mTorr to 1 Torr. Rutherford backscattering spectrometry (RBS) and x-ray photoelectron spectroscopy were used to obtain stoichiometric information. A very strong pressure dependence of the O/Zr ratio was observed. While the trend of increasing O/Zr and Zr/Y ratio with increasing O2 pressure is apparent, the correlations between O/Zr as well as Zr/Y ratio and other processing conditions are less obvious. RBS results indicate an increasing roughness at the interface between the ZrO2 film and the sapphire substrate as the oxygen pressure exceeds 50 mTorr. The structural information obtained from x-ray diffraction patterns indicates broadening of peak width with increasing laser fluence as well as decreasing substrate temperature. For the film deposited at a lower substrate temperature, a strong (002) texture was observed.

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Effects of Processing Parameters on KrF Excimer Laser Ablation Deposited ZrO2 Films

MRS Proceedings ◽

10.1557/proc-235-843 ◽

1991 ◽

Vol 235 ◽

Cited By ~ 3

Author(s):

Gary A. Smith ◽

Li-Chyong Chen ◽

Mei-Chen Chuang

Keyword(s):

Laser Ablation ◽

Substrate Temperature ◽

Excimer Laser ◽

Deposition Rate ◽

Oxygen Pressure ◽

Pressure Dependence ◽

Laser Fluence ◽

X Ray ◽

Excimer Laser Ablation ◽

Krf Excimer Laser

ABSTRACTSystematic experiments have been carried out to characterize the yttria containing zirconia thin films on sapphire substrates by 248nm KrF excimer laser ablation. The deposition rate as a function of laser fluence and O2 pressure at room temperature was measured with a quartz crystal microbalance. The results show different threshold fluences for deposition in vacuum vs. oxygen. While the deposition rate increases with increasing fluence at a given oxygen pressure, the rate eventually saturates at a higher laser fluence. At a given fluence, the oxygen pressure dependence of the deposition rate shows a radical reduction when the O2 pressure increases from 10 mTorr to 1 Torr. Rutherford backscattering spectrometry (RBS) and x-ray photoelectron spectroscopy were used to obtain stoichiometric information. A very strong pressure dependence of the O/Zr ratio was observed. While the trend of increasing O/Zr and Zr/Y ratio with increasing O2 pressure is apparent, the correlations between O/Zr as well as Zr/Y ratio and other processing conditions are less obvious. RBS results indicate an increasing roughness at the interface between the ZrO2 film and the sapphire substrate as the oxygen pressure exceeds 50 mTorr. The structural information obtained from x-ray diffraction patterns indicates broadening of peak width with increasing laser fluence as well as decreasing substrate temperature. For the film deposited at a lower substrate temperature, a strong (002) texture was observed.

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Selective Deposition of ZnS Thin Films by KrF Excimer Laser on Patterned Zn Seeds

MRS Proceedings ◽

10.1557/proc-334-257 ◽

1993 ◽

Vol 334 ◽

Author(s):

K. Yamane ◽

M. Murahara

Keyword(s):

Excimer Laser ◽

Substrate Surface ◽

Chemical Vapor ◽

Reaction Chamber ◽

Chemical Vapor Deposition Method ◽

Single Shot ◽

Laser Chemical Vapor Deposition ◽

Krf Laser ◽

Krf Excimer Laser ◽

Zns Films

AbstractThe patterned Zn nucleation and the ZnS growth onto the Zn seeds on a thermal oxidized silicon substrate was demonstrated at room temperature with the excimer laser chemical vapor deposition method.The formation of ZnS films was realized by the method based on the two—step process consisting of the nucleation and the subsequent ZnS growth. In the nucleation, a gaseous dimethylzinc was sealed in a reaction chamber and was then evacuated immediately. Then, the substrate surface which was uniformly adsorbed by dimethylzinc molecules was exposed with a single shot irradiation of a patterned KrF laser; Zn seeds were created only on the irradiated parts by a photodecomposition. And the subsequent growth of ZnS was performed by the parallel or perpendicular irradiation methods. As a result, in the perpendicular irradiation method, the high selectivity and crystallinity of the film were performed by irradiating the whole substrate surface with very low fluence of the KrF laser such as 3 mJ/cm2.

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