Pulsed laser deposition using diffractively shaped excimer-laser beams

V. Kekkonen (Corresponding Author), Antti Hakola, Jari Likonen, Y. Ge, T. Kajava

    Research output: Contribution to journalArticleScientificpeer-review

    3 Citations (Scopus)

    Abstract

    Controlling laser-pulse parameters is an important issue in pulsed laser deposition (PLD). In particular, homogenization of laser beams improves the reproducibility of the PLD process by guaranteeing a uniform intensity distribution and a well-defined energy density of the laser spot on the target. We have integrated a beam-homogenization system into our PLD setup, and here we discuss the results and advantages of using such a system. The optical setup is based on diffractive beam-splitter gratings, which produce a 2×2-mm2 flat-top distribution with fluences of the order of 3 J/cm2 on the target. We demonstrate the applicability of this technique by depositing thin films of ferromagnetic Ni–Mn–Ga shape-memory alloys. Magnetic and structural characterization, including secondary ion mass spectrometry (SIMS), indicate that nearly stoichiometric composition and crystallization in the desired martensitic phase is obtained for films deposited on Al2O3 under optimal conditions. In contrast, the formation of silicide compounds at temperatures above 500 C is detrimental in the deposition of Ni–Mn–Ga films directly on silicon.
    Original languageEnglish
    Pages (from-to)423-430
    Number of pages8
    JournalApplied Physics A: Materials Science and Processing
    Volume108
    Issue number2
    DOIs
    Publication statusPublished - 2012
    MoE publication typeA1 Journal article-refereed

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