Laser Ablation-Implantation

A scheme of the experimental setup is shown in Fig. 83, where a laser beam (355 nm, 3 ns) is directed from the rear of the target film onto the triazene polymer film (doped with pyrene) as shown in Fig. 82. The laser fluence was estimated by averaging the total energy of the incident beam over the irradiated area. The target films [poly(butyl methacrylate), PBMA, Tg=293 K and poly(ethyl methacrylate), PEMA, Tg=338 K] were characterized with a fluorescence microscope and a conventional spectrofluo-rometer. 

---

Hiroshi Fukumura received his M.Sc and Ph.D. degrees from Tohoku University, Japan. He studied biocompatibility of polymers in the Government Industrial Research Institute of Osaka from 1983 to 1988. He became an assistant professor at Kyoto Institute of Technology in 1988, and then moved to the Department of Applied Physics, Osaka University in 1991, where he worked on the mechanism of laser ablation and laser molecular implantation. Since 1998, he is a professor in the Department of Chemistry at Tohoku University. He received the Award of the Japanese Photochemistry Association in 2000, and the Award for Creative Work from The Chemical Society Japan in 2005. His main research interest is the physical chemistry of organic molecules including polymeric materials studied with various kinds of time-resolved techniques and scanning probe microscopes. 

Before mild chemical routes to high quality NCs were widely available, NCs were prepared in glasses by such strategies as precipitation, ion implantation, and laser ablation, which typically rely on high-temperature processing... 

Most of the time, metal/dielectric nanocomposites are studied in the form of solutions or thin solid films on a substrate Colloids, doped and annealed glasses, sol-gels, surfactant-stabilized nanoparticles, micelles, two- or three-dimension self-assembled nanocomposites, self-organized mesoporous oxides filled with metals, electrochemically-loaded template membranes, metal-ion implanted crystals, nanocomposite films elaborated by laser ablation, cluster-beam deposition, radio-frequency sputtering, or nanolithography. 

Surgery to correct refractive errors for the improvement of visual acuity generally aims at changing the corneal curvature. Corneal tissue is mainly constituted of a network of natural collagen polymer with the void volume filled with a special type of aqueous saline solution. A wide variety of laser and nonlaser procedures, such as laser-assisted in situ keratomileusis (LA-SIK), laser-cut channels for intracorneal ring segment (ICRS) implantation, femtosecond lamellar keratoplasty (FLK), intrastromal vision correction, and corneal transplantation have been developed for refractive surgical correction [83, 84]. They include removal of corneal tissue from the surface, removal of corneal tissue from the interior or stroma, and alteration of the corneal mechanical properties to produce a refractive effect. The most popular by far are procedures based on excimer laser ablation of the corneal surface and/or stroma [85]. 

Li, E, Balazs, M.K., Pong, R. (2000) Total dose measurement for ion implantation using laser ablation ICP-MS. Journal of Analytical Atomic Spectrometry, 15, 1139-1141. 

Ghazi, A. M., Wataha, J. C., O DeU, N. L., Singh, B. B., Simmons, R, Shuttleworth, S. (2002) Quantitative concentration profiling of nickel in tissues around metal implants a new biomedical application of laser ablation sector field ICP-MS. J Anal At Spectrom, 17, 1295. 

Nanocrystallization via dewetting of materials has been observed in processing techniques, including ion implantation followed by thermal annealing, laser ablation, high-vacuum deposition, and molecular beam epitaxy In this section we focus on... 

Ion implantation has become the dominant doping technique, particularly in the fabrication of bipolar-CMOS devices and in the formation of shallow junctions. Laser ablation sampling coupled with ICP-MS was applied recently to the determination of total dopant dose. Since this technique spatially and temporally separates the sampling and ionization steps, it has the potential to produce more quantitative results than SIMS for trace elements in a given matrix. Wafer surface analysis can also be used to monitor the contamination induced hy different process steps. The importance, in terms of contamination contrihution, of the chamber components used for film deposition and ion implantation was demonstrated, as was the effect of cleaning bath solution purity. ... 

Fig. 86 Fluorescence spectra of a pyrene-implanted PBMA surface as a function of laser pulse number. Pyrene was transferred using ablation of a triazene polymer. Laser flu-ence 100 mj creT2, (a) 5 pulses, (b) 10 pulses, (c) 15 pulses, (d) 20 pulses. The vibrational pyrene emission peaks are denoted (I-V). Inset Normalized fluorescence intensity of the V pyrene peak at 393 nm vs laser pulse number. Data are taken from the spectra in the main figure. REPRINTED WITH PERMISSION OF [Ref. 360], COPYRIGHT (1998) Elsevier Science...

With its analysis speed, LA-ICP-MS lends itself for quick checks of film consistency (e.g., for metal interconnects or hard disk platters) [96]. The fact that the ablation volume per laser shot can be rather large in comparison with pulsed ions can be utilized to measure the total dopant dose of ion implantation. Here the distribution of the dopant is not depth profiled step by step as with SIMS, but the laser parameters are chosen... 

---