Laser-induced fluorescence analysis of plasmas for epitaxial growth of YBiO3 films with pulsed laser deposition

Kasper Orsel,Gertjan Koster,Guus Rijnders,Klaus-J Boller,Rik Groenen,Bert Bastiaens

doi:10.1063/1.4971349

Abstract

We record the two-dimensional laser-induced fluorescence (LIF) on multiple plasma constituents in a YBiO3 plasma. This allows us to directly link the influence of oxygen present in the background gas during pulsed laser deposition to the oxidation of plasma species as well as the formation of epitaxial YBiO3 films. With spatiotemporal LIF mapping of the plasma species (Y, YO, Bi, and BiO) in different background gas compositions, we find that little direct chemical interaction takes place between the plasma plume constituents and the background gas. However, a strong influence of the background gas composition can be seen on the YBO film growth, as well as a strong correlation between the oxygen fraction in the background gas and the amount of YO in the plasma plume. We assign this correlation to a direct interaction between the background gas and the target in between ablation pulses. In an O2 background, an oxygen-rich surface layer forms in between ablation pulses, which provides additional oxygen for the plasma plume during target ablation. This differs from our previous observations in STO and LAO plasmas, where species oxidation primarily takes place during propagation of the plasma plume towards the substrate.

Highlights

It is widely accepted that pulsed laser deposition (PLD) allows for the stoichiometric transfer of complex materials, making it a very powerful and universal deposition technique for the growth of thin films of complex crystalline oxides such as to impose ferro-electricity,[1] two-dimensional electron gases at heterointerfaces,[2] or superconductivity at interfaces,[3] among other applications.[4]
A central question is, e.g., to what degree Bi is oxidized by the O2 background gas before deposition onto the substrate or whether the oxygen background rather leads to oxidation only at the substrate, after an atomic deposition of Bi and Y
In our previous work involving SrTiO317 and LaAlO318 we have found that the plasma dynamics and chemistry and, where and when in the plume oxidation occurs, is of decisive influence on the morphology of the grown films

Summary

Introduction

It is widely accepted that pulsed laser deposition (PLD) allows for the stoichiometric transfer of complex materials, making it a very powerful and universal deposition technique for the growth of thin films of complex crystalline oxides such as to impose ferro-electricity,[1] two-dimensional electron gases at heterointerfaces,[2] or superconductivity at interfaces,[3] among other applications.[4].

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Conclusion