Material Removal and Deposition by Pulsed Laser Ablation and Associated Phenomena
This chapter starts with the presentation of some micro and nano requirements by describing some influences of the ambient gas and target material on the ablation process in general and on the ablation rate in particular. Ablation in liquids is also brief
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Material Removal and Deposition by Pulsed Laser Ablation and Associated Phenomena
Abstract This chapter starts with the presentation of some micro and nano processing requirements by describing some influences of the ambient gas and target material on the ablation process in general and on the ablation rate in particular. Ablation in liquids is also briefly presented as an alternative ablation technique. Nanoparticle formation from the ablation plume is further explained based on basic homogeneous condensation theory. In the last part the PLD process is presented through its basic components: ablation, plume propagation and particle deposition. Special attention is given to the plume propagation and filtering techniques. ‘Classical’ filtering techniques as axe-off, back-side and ‘eclipse’ techniques are described starting from the plume propagation. Also some more advanced multi-element masks and a more recent filtering technique based on the plume reflection developed by the authors are presented and described in this chapter.
5.1 Micro and Nano Processing (Patterning) of Materials by PLA The laser is increasingly used in the field of material processing due to its unique advantages: high productivity, automation and non-contact processing, improved product quality with elimination of finishing operation requirement, reduced processing cost, greater material utilization, and minimum heat affected zone [1–10]. The most suitable laser sources for obtaining very small (micrometer and sub-micrometer) and high quality structures are the femtosecond lasers due to the reduced thermal effects induced even into metallic targets [11–13]. However, the high-costs for acquisition and long-time running, as well as the technical difficulties in keeping constant parameters for these lasers, limit the number of fs lasers users. Actually, most of the research groups worldwide that work in the field of PLA use ns and ps lasers (such as Nd-YAG and Nd fiber lasers) which are more reliable and cost efficient [12–14]. The studies propose to determine the optimum laser and
M. Stafe et al., Pulsed Laser Ablation of Solids, Springer Series in Surface Sciences 53, DOI: 10.1007/978-3-642-40978-3_5, © Springer-Verlag Berlin Heidelberg 2014
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5 Material Removal and Deposition by Pulsed Laser Ablation
Fig. 5.1 a Classifications of laser material processing [21, 22]. b Laser processes map in terms of laser power density and interaction time. Different examples of laser material processing are indicated [4, 21, 22]
ambient parameters that allow one to obtain high quality micro- and nano-structures on different materials. Figure 5.1a presents a classification of the laser material processing techniques which can be grouped into two categories: • applications requiring limited energy/power which induces no significant change of phase or state; • applications requiring substantial amount of energy to induce the phase transformations. The first category includes processes such as laser annealing and etching, scribing- marking of integr
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