Laser induced etching

Matsui Y, Adachi S (2012) Optical properties of porous silicon layers formed by electroless photovoltaic etching. ECS J Solid State Sci Technol 1 R80-R85 Mavi HS, Rasheed BG, Soni RK, Abbi SC, Jain KP (2001) Photoluminescence and Raman study of porous silicon synthesized by visible and infrared laser etching. Thin Solid Films 397 125-132 Mavi HS, Prusty S, Kumar M, Kumar R, Shukla AK, Rath S (2006) Formation of Si and Ge quantum structures by laser-induced etching. Phys Status Solidi A 203 2444-2450 Noguchi N, Suemune I (1993) Luminescent porous silicon synthesized by visible fight irradiation. Appl Phys Lett 62 1429-1431... 

As shown in Fig. 5.11, there are many different methods that could be used for Si porosification. It was established that, besides conventional electrochemical etching, chemical stain etching, chemical vapor etching, spark processing, laser-induced etching, and reactive ion etching could be used. 

Anodic Etching Chemical Stain Etching Chemical Vapor Etching Laser-Induced Etching Metal-Assisted Etching Spark Processing Reactive Ion (Plasma) Etching... 

Grebel H, Iskandar B, Pien P, Sheppard K. In situ monitoring of a laser-induced etched grating on InP, thin-film cell configuration. Appl Phys Lett 1990 57 2959-2961. 

Laser induced etching is also described by Rytz-Froidevaux et al. [434]. Laser induced etching processes are mainly used in microelectronics. 

Hargis, P. J., Jr., and M. J. Kushner. Detection of CF2 radicals in a plasma etching reactor by a laser induced fluorescence spectroscopy. 

Fig. 37 Schematic diagram of laser-induced decomposition and ablation dynamics of the photosensitive triazene polymer film (a) before excimer laser irradiation, (b) slight expansion of the film and darkening of the irradiated surface at the beginning of the excimer laser pulse, (c) initiation of etching of the film and ejection of gaseous fragments decomposed from the polymer, (d) completion of the etching and expansion of ejected plume, and (e) after the ablation. REPRINTED WITH PERMISSION OF [Ref. 125], COPYRIGHT (1997) American Chemical Society...

Important plasma diagnostics include Langmuir probes, optical emission spectroscopy, laser induced fluorescence, absorption spectroscopy, mass spectrometry, ion flux and energy analysis, and plasma impedance analysis. A plasma reactor equipped with several of these diagnostics is shown in Fig. 51 [35, 160]. A capacitively coupled plasma is sustained between the parallel plates of the upper (etching) chamber. The lower (analysis) chamber is differentially pumped and communicates with the etching chamber through a pinhole on the lower electrode. 

Finally in this Section on infrared photochemistry, the i.r. laser-induced reaction of SF with a Si surface has been described. Pulsed COj laser radiation in the absence of SF causes momentary heating of a Si target, but no Si removal in the presence of a few Torr of SF, etching of the Si is observed. The mechanism for the process is yet to be established, but it appears that both the reactions of excited species produced by the laser, and the effect of the laser radiation at the gas-surface interface are of importance. ... 

Capillary electrophoresis is an excellent microseparation technique that has been used for the separation of a wide diversity of different molecules." Its separation capabilities extend to ions, small molecules (such as amino acids), and large biomolecules (such as peptides, proteins, and nucleic acids). Indeed the human genome project owes its success, in part, to the use of CE for the separation of DNA bases. In the past, CE has been combined with detection devices such as ultraviolet (UV) and laser-induced fluorescence (LIE) spectrophotometers. The detection of the separated analytes is carried out on column by etching the capillary. Unfortunately, UV detection lacks sensitivity and not every compound of interest will absorb in the UV region of the spectmm. Detection using LIE is sensitive, however, the analytes of interest may require derivatization with a fluorescent tag or have an aromatic amino acid in their structure (e.g., proteins and peptides). An advantage of MS detection that neither UV nor LIE detection provides is the information necessary to directly determine the structure of the detected analyte(s). 

Wcssman reviewed a number of instruments used for uranium analyses and ranked their relative measurement sensitivities [32]. The methods include atomic absorption spectrophotometry, colorimetry, neutron bombardment, fission etched track detectors, fluorimetry, laser-induced fluorescence spectrometry, a-spectrometry, isotope dilution mass spectrometry, and spark source mass spectrometry. The majority of urinary bioassay measurements have been performed by fluorimetry, while environmental survey and baseline measurements have been performed by fluorimetry, a-spectrometry, and induced coupled plasma source mass spectrometry. 

At temperatures of 1 K, all substances except for He (and certain spin-polarized species, such as atomic hydrogen) have negligible vapor pressure, so the question arises as to how to bring the species to be cooled into the gas phase and then into the buffer gas. Five methods have been used to accomplish this laser ablation, beam injection, capillary filling, discharge etching, and laser-induced atom desorption (LIAD). 

Laser-induced plasma Etching (dry) Macroporous Kabashin and Meunier (2002) 2002 ... 

The degree of polymer crystallinity may be controlled by using controlled laser-induced texturing. Laser etching improves adhesion to polymers because texturing increases the surface area. 

Ding, X. Yasui, Y Kawaguchi, Y Niino, H. Yabe, A. Laser-induced back-side wet etching of fused silica with an aqueous solution containing organic molecules. Appl. Phys. A Mater. Sci. Process. 2002, 75,437-440. 

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