Impact of high-temperature annealing of AlN layer on sapphire and its thermodynamic principle

Hiroyuki Fukuyama, Hideto Miyake, Gou Nishio, Shuhei Suzuki, Kazumasa Hiramatsu

Research output: Contribution to journalArticle

21 Citations (Scopus)

Abstract

The N2-CO gas annealing technique was demonstrated to improve the crystalline quality of the AlN layer on sapphire. 300-nm-thick AlN layers were fabricated on sapphire substrates by a metal-organic vapor phase epitaxy method. The AlN layers were annealed in N2 and/or N2-CO gas atmosphere at 1923-1973K for 0.5-4 h. Many pits and voids were observed on the AlN surface annealed in N2 atmosphere at 1973K for 2 h. The rough surface was, however, much improved for the AlN annealed in N2-CO gas atmosphere. The thermodynamic principle of the N2-CO gas annealing technique is explained in this paper on the basis of the phase stability diagram of the Al2O3-AlN-C-N2-CO system. Voids and γ-aluminum oxynitride (γ-AlON) at the AlN/sapphire interface formed during the annealing, which is also explained on the basis of the phase stability diagram. The in-plane epitaxial relationships among AlN, γ-AlON, and sapphire are presented, and misfits among them are discussed.

Original languageEnglish
Article number05FL02
JournalJapanese journal of applied physics
Volume55
Issue number5
DOIs
Publication statusPublished - 2016 May

ASJC Scopus subject areas

  • Engineering(all)
  • Physics and Astronomy(all)

Fingerprint Dive into the research topics of 'Impact of high-temperature annealing of AlN layer on sapphire and its thermodynamic principle'. Together they form a unique fingerprint.

  • Cite this