Effects of TiN buffer layer thickness on GaN growth

Kazuhiro Ito, Yu Uchida, Sangjin Lee, Susumu Tsukimoto, Yuhei Ikemoto, Koji Hirata, Masanori Murakami

    Research output: Contribution to journalArticlepeer-review

    2 Citations (Scopus)

    Abstract

    Smooth GaN layers were successfully grown on metallic TiN buffer layers by metalorganic chemical vapor deposition (MOCVD). One important factor in controlling GaN layer smoothness was the TiN layer thickness. We investigated systematically the effects of this thickness, and found an optimal thickness of 5 nm, at which the smallest average grain size (20 nm) and smoothest surface were obtained. The TiN layers increased surface coverage with GaN hexagons at an early stage of GaN growth, indicating that enhancing the GaN nucleation is essential for smooth GaN layer growth, and small grain size and smooth surface are needed to enhance GaN nucleation. Further reduction in TiN layer thickness to 2 nm decreased the surface coverage with GaN hexagons, and a high density of grooves and holes were observed in the surface of the 2-μm-thick GaN layers. Defect structures in the GaN layers grown on the TiN layers were remarkably changed on reduction of TiN layer thickness from 5 nm to 2 nm. GaN growth was found to be sensitive to the TiN layer thickness between 2 nm and 5 nm.

    Original languageEnglish
    Pages (from-to)511-517
    Number of pages7
    JournalJournal of Electronic Materials
    Volume38
    Issue number4
    DOIs
    Publication statusPublished - 2009 Apr

    Keywords

    • Dislocations
    • Epitaxial growth of GaN
    • TiN buffer layers
    • TiN layer thickness

    ASJC Scopus subject areas

    • Electronic, Optical and Magnetic Materials
    • Condensed Matter Physics
    • Electrical and Electronic Engineering
    • Materials Chemistry

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