pulsed laser deposition otherwise PLD (rus. импульсное лазерное напыление) — obtaining films and coatings by condensating the products of interaction of pulsed laser radiation and target material in vacuum (ablation) on a substrate.

Description

The pulsed laser deposition method belongs to a group of physical vapour deposition methods. The interaction of a high-energy laser pulse with the target material results in a variety of products, including not only electrons, ions and neutral particles, but also solid microparticles of the target material coming off during flash evaporation of the material. The trajectory of further movement of these particles and their distribution by energy significantly depend not only on the intensity, duration and frequency of laser pulses, but also on the pressure in the chamber. The laser ablation in high vacuum leads to the formation of a narrow plume of products with a high proportion of charged particles; in film production under these conditions an important role is played by the processes of secondary spraying of the condensate by high-charged particles.

On the contrary, if the pressure in the chamber is increased, the cloud of ablation products consists mainly of neutral particles, its properties approaching the properties of low pressure steam.

Production of high-quality films and coatings in these conditions is a complex scientific and technical problem which has already been successfully resolved for a number of materials. The main advantage of laser ablation is, above all, the high degree of conformity of the cation stoichiometry of the films to the composition of the target material, which causes serious difficulties in many other methods and is particularly important in the deposition of multicomponent materials. The high degree of supersaturation in the condensation of ablation products leads to intense nucleation across the surface of the substrate, and results in high morphological homogeneity in the film. The method is also characterised by a very high deposition rate as compared to other thin-film methods, which, however, allows producing high crystallinity films. An important factor is the almost complete absence of film contamination by materials of the chamber and auxiliary devices resulting from the small beam width. The emitter location outside of the vacuum chamber enables wide-range changes to the gas atmosphere during the deposition. The disadvantages of the method include the small geometrical size of the homogeneous deposition area in vacuum ablation, due to the small diameter of the ablation products plume, and possible contamination of the film by particles and droplets of molten target material at high rates of deposition.

Authors

  • Shlyakhtin Oleg A.
  • Naymushina Daria A.

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