Relative effects of pulsed laser deposition parameters on the stoichiometry of thin films

Abstract

Pulsed laser deposition has a reputation for maintaining the stoichiometry of the ablation target in the deposited film. Exceptions to this "rule" occur, however, for materials, such as multiferroic BixDy(1-x)FeO3 (BDFO), that contain elements with large differences in volatility, like Bi and Fe. The relative effect of various pulsed laser deposition processes on the resulting stoichiometry of BDFO films as a function of time (or number of laser pulses) has been examined using an interactive spreadsheet, as well as experimentally. The adjustable parameters within the spreadsheet include target composition, target element ablation yield, ablation plume spread, background gas pressure, ablated target atom kinetic energy, and ablated element sticking coefficient on the substrate. Examples of how the calculated film composition might evolve are given, along with experimental results showing how the deposition parameters individually affect BDFO film stoichiometry. Finally, the calculated relative contributions of the various deposition processes, in terms of how much they affect the deposited film stoichiometry, are compared.