Laser Ablation Deposition: Mechanism and Application

Especially in the eighties and early nineties laser ablation has drawn increasing attention for application in thin film deposition (and etching). For a variety of inorganic materials, at the practically most interesting laser fluence values just above the ablation threshold, the pulsed ablation clouds arriving at the substrate consist mainly of ground state atoms (≥99%, E kin ∼a few eV), Rydberg atoms (∼0.1 to 1%, E kin ∼near 10 eV), positive ions (≤10 -2 %, E kin ∼a few tens eV), electrons and “droplets”. The atoms are strongly peaked along the target surface normal, while the angular distribution of the ions is largely isotropic. A hydrodynamic model describes the ablation cloud quite well. As compared to other advanced thin film deposition techniques, laser ablation deposition produces high-quality, stoichiometric films of even very complex materials at lower substrate temperatures.