Cohesive Properties of Semiconductors under Laser Irradiation


Book Description

The impact of Materials Science in our environment has probably never been as massive and decisive as it is today. In every aspect of our lives, progress has never been so dependent on the techniques involved in producing ever more sophisticated materials in ever larger quantities, nor so demanding for technologists to imagine novel processes and circumvent difficulties, or take up new challenges. Every technique is based on a physical process which is put into practice and optimized. The better we know that process, the better the optimization, and more powerful the technique. Laser processing of materials is inscribed in that context. As soon as powerful coherent light sources were made available, it was realized that such intense sources of energy could be used to "heat, melt and crystallize" materials, i.e., to promote phase transitions in atomic systems. As early as 1964, attempts in that direction were made but received very little (if any) attention. Reasons for this lack of interest were several. For one thing, laser technology was not fully developed, so that the process offered poor reliability and no versatility. Also, improving the existing techniques was believed to be sufficient to meet the needs of the time, and there was no real motivation to explore new ways. Finally, and more important, the fundamentals of the physics behind the scenes were, and continue to be, way out of the runni~g stream.




Interfaces Under Laser Irradiation


Book Description

Known and developed over the past twenty five years, lasers have been experimented in a variety of processes with an uneven success. Apart from fundamental physics experiments in which the various aspects of coherence are systematically exploited, applications in the field of Materials Science have been scattered recently over so many situations that it is apparently difficult today to conceive a comprehensive interpretation of all physical processes encountered. In some domains of research like photochemistry, development has been fast and rather self-supporting. In others, like solid-state processing, progress has been either very specific or deviated towards marginal applications, or else emerged as a joint-venture between physicists and chemists. This yielded a number of professional meetings, where day-to-day research activities are presented. In 1982, the Cargese ASI on "Cohesive properties of semiconductors under laser irradiation" was one of such meetings at which a prospective of the field was discussed at length in ebullient round-table sessions. Quoted from the proceedings, "the Institute helped to discern clearly the limits of existing theoretical approaches and the directions along which work is urgently needed within the next few years". Four years have passed and the field has literally explo ded. It must be mentioned that some of the most striking developments over the past two years were accurately predicted at the Institute in Cargese.







Semiconductors Probed by Ultrafast Laser Spectroscopy Pt II


Book Description

Semiconductors Probed by Ultrafast Laser Spectroscopy, Volume II discusses the use of ultrafast laser spectroscopy in studying fast physics in semiconductors. It reviews progress on the experimental and theoretical understanding of ultrafast events that occur on a picosecond and nanosecond time scale. This volume discusses electronic relaxation in amorphous semiconductors and the physical mechanisms during and after the interaction of an intense laser pulse with a semiconductor. It also covers the relaxation of carriers in semiconductors; transient optical pulse propagation; and methods of time-resolved spectroscopy. Scientists, engineers, and graduate students will find this book invaluable.




Laser-Assisted Microtechnology


Book Description

Laser-Assisted Microtechnology introduces the principles and techniques of laser-assisted microtechnology with emphasis on micromachining of thin films, microprocessing of materials, maskless laser micropatterning and laser-assisted synthesis of thin-film systems. The experimental and theoretical physico-chemical basis of every technological process is presented in detail. On the basis of some characteristic examples of applications, the capabilities of the technological methods as well as the optimum conditions for their realization are discussed. In this second edition, besides the actualization of the literature, a new chapter concerning the laser-assisted wet chemical micro etching, has been added. This is a new method for direct 3D-micro structuring of solids, with a number of potential applications.




Surface Processing and Laser Assisted Chemistry


Book Description

The papers in this volume cover all aspects of laser assisted surface processing ranging from the preparation of high-Tc superconducting layer structures to industrial laser applications for device fabrication. The topics presented give recent results in organometallic chemistry and laser photochemistry, and novel surface characterization techniques. The ability to control the surface morphology by digital deposition and etching shows one of the future directions for exciting applications of laser surface processing, some of which may apply UV and VUV excitation. The understanding of elementary proceses is essential for the design of novel deposition methods, with diamond CVD being an outstanding example. The high quality of these contributions once again demonstrates that the E-MRS is an efficient forum for interaction between research workers and industry.




Laser Ablation and Desorption


Book Description

This volume introduces the subject of laser ablation and desorption to scientists and engineers. It covers fundamental experimental and theoretical tools, models, and techniques, and introduces the most important applications. Clearly written and organized in a straightforward manner, Laser Ablation and Desorption lead the reader straight through the fundamentals of laser-surface interactions. Each chapter is self-contained and includes references to other chapters as necessary, so that readers may begin with the topic of greatest interest and follow the references to other aspects of the subject contained within the book.Key Features* Provides up-to-date information about one of the most active fields in physics today* Written and edited by major figures in the field of laser ablation and desorption* Represents the most comprehensive treatment of the state-of-the-art available




Laser Ablation


Book Description

Laser Ablation provides a broad picture of the current understanding of laser ablation and its many applications, from the views of key contributors to the field. Discussed are in detail the electronic processes in laser ablation of semiconductors and insulators, the post-ionization of laser-desorbed biomolecules, Fourier-transform mass spectroscopy, the interaction of laser radiation with organic polymers, laser ablation and optical surface damage, laser desorption/ablation with laser detection, and laser ablation of superconducting thin films.




Laser Processing and Diagnostics


Book Description

Laser processing is now a rapidly increasing field with many real and potential applications in different areas of technology such as micromecha nics, metallurgy, integrated optics, and semiconductor device fabrication. The neces s ity for such soph i st i cated 1 i ght sources as 1 asers is based on the spatial coherence and the monochromaticity of laser light. The spatial coherence permits extreme focussing of the laser light resulting in the availability of high energy densities which can be used for strongly loca lized heat- and chemical-treatment of materials, with a resolution down to 1 ess than 1 lJIll. When us i ng pul sed or scanned cw-l asers, 1 oca 1 i zat i on in time is also possible. Additionally, the monochromaticity of laser light allows for control of the depth of heat treatment and/or selective, nonthermal bond breaking - within the surface of the material or within the molecules of the surrounding reactive atmosphere - simply by tuning the laser wavelength. These inherent advantages of laser light permit micromachining of materials (drilling, cutting, welding etc.) and also allow single-step controlled area processing of thin films and surfaces. Processes include structural transformation (removal of residual damage, grain growth in polycrystalline material, amorphization, surface hardening etc.), etching, doping, alloying, or deposition. In addition, laser processing is not 1 imited to planar substrates.




Laser Surface Treatment of Metals


Book Description

Proceedings of the NATO Advanced Study Institute, San Miniato, Italy, September 2-13, 1985