DC voltage fields generated by RF plasmas and their influence on film growth morphology through static attraction to metal wetting layers: beyond ion bombardment effects

K. S. A. Butcher, P. T. Terziyska, R. Gergova, V. Georgiev, D. Georgieva, P. W. Binsted, S. Skerget

    Research output: Contribution to journalArticlepeer-review

    2 Citations (Scopus)
    58 Downloads (Pure)

    Abstract

    It is shown that attractive electrostatic interactions between regions of positive charge in RF plasmas and the negative charge of metal wetting layers, present during compound semiconductor film growth, can have a greater influence than substrate temperature on film morphology. Using GaN and InN film growth as examples, the DC field component of a remote RF plasma is demonstrated to electrostatically affect metal wetting layers to the point of actually determining the mode of film growth. Examples of enhanced self-seeded nanopillar growth are provided in the case where the substrate is directly exposed to the DC field generated by the plasma. In another case, we show that electrostatic shielding of the DC field from the substrate can result in the growth of Ga-face GaN layers from gallium metal wetting layers at 490 °C with root-mean-square roughness values as low as 0.6 nm. This study has been carried out using a migration enhanced deposition technique with pulsed delivery of the metal precursor allowing the identification of metal wetting layers versus metal droplets as a function of the quantity of metal source delivered per cycle. It is also shown that electrostatic interactions with the plasma can affect metal rich growth limits, causing metal droplet formation for lower metal flux than would otherwise occur. Accordingly, film growth rates can be increased when shielding the substrate from the positive charge region of the plasma. For the example shown here, growth rates were more than doubled using a shielding grid.

    Original languageEnglish
    Article number013301
    Pages (from-to)1-13
    Number of pages13
    JournalJournal of Applied Physics
    Volume121
    Issue number1
    DOIs
    Publication statusPublished - 2017

    Bibliographical note

    Copyright 2017 AIP Publishing. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Journal of Applied Physics 121, 013301 (2017) and may be found at https://doi.org/10.1063/1.497348.

    Fingerprint

    Dive into the research topics of 'DC voltage fields generated by RF plasmas and their influence on film growth morphology through static attraction to metal wetting layers: beyond ion bombardment effects'. Together they form a unique fingerprint.

    Cite this