Pulsed laser deposition: a new technique for deposition of amorphous SiOx thin films

Pulsed laser deposition (PLD) is a physical vapour deposition coating technique for the production of thin films with complex chemical compositions. One of the main advantages of PLD is that excellent coating properties can be achieved even at low deposition temperatures. However, particulate defects in the growing films resulting from the evaporation process are often mentioned as the most important disadvantages of the PLD process. Unfavourable optical, thermo-physical and mechanical properties of the target material evaporated by laser radiation promote the formation of particulate defects. This paper presents some results on silicon-based PLD-films with reduced density of particulates. Silicon, SiOx and SiO2 thin films were deposited by laser ablation from silicon targets with a high power pulsed Nd:YAG laser of 1064 nm wavelength in argon and oxygen containing atmospheres. The substrates were arranged in shaded off-axis geometry. The chemical composition and structure of the films were investigated employing transmission electron microscopy (TEM), secondary ion mass spectroscopy, X-ray photoelectron spectroscopy and ellipsometry. The results demonstrate the capability of PLD for the deposition of SiOx films with varying composition (0⩽x⩽2) by shaded off-axis PLD. The results of TEM and spectroscopic ellipsometry are indicating amorphous film structures in all cases.