Electron microscopy analysis of dislocation behavior in HVPE-AlGaN layer grown on a stripe-patterned (0 0 0 1) sapphire substrate

Noriyuki Kuwano, Yuta Kugiyama, Yutaka Nishikouri, Tadashige Sato, Akira Usui

Research output: Contribution to journalArticlepeer-review

10 Citations (Scopus)

Abstract

Microstructures were investigated by transmission electron microscopy (TEM) and scanning electron microscopy (SEM) in order to clarify the dislocation behavior in AlGaN layers HVPE-grown on a stripe-patterned sapphire (0 0 0 1) substrate. SEM observation revealed very clearly the growth process: if AlGaN starting to grow from the side-wall of patterned substrate develops, a poly-crystalline region is formed up to the top surface of thin film. When the growth from the upper side (terrace) of patterned substrate is predominant, AlGaN becomes a single-crystalline layer with a flat surface. Threading dislocations (TDs) generated from the interface to the terrace propagate upwards, inclining to the wing regions. They are scarcely merged with one another. The AlGaN layer on the patterned substrate with a wider groove has a smaller density of dislocation to be about 1×109 cm-2. There are four types of dislocations: (1) TDs inclining toward 〈1 1̄ 0 0〉 normal to their Burgers vector B; (2) TDs inclining toward 〈2 1̄ 1̄ 0〉 on their slip-plane; (3) TDs inclining largely or horizontal dislocations (HDs) along 〈2 1̄ 1̄ 0〉 and (4) roundly curved HDs lying on (0 0 0 1) plane. Some TDs change the direction of inclination, suggesting that internal stress changed intricately during the growth.

Original languageEnglish
Pages (from-to)3085-3088
Number of pages4
JournalJournal of Crystal Growth
Volume311
Issue number10
DOIs
Publication statusPublished - 2009 May 1

Keywords

  • A1. Electron microscopy
  • A3. Hydride vapor phase epitaxy
  • B1. Nitrides

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Inorganic Chemistry
  • Materials Chemistry

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