TY - JOUR
T1 - Impact of high-temperature annealing of AlN layer on sapphire and its thermodynamic principle
AU - Fukuyama, Hiroyuki
AU - Miyake, Hideto
AU - Nishio, Gou
AU - Suzuki, Shuhei
AU - Hiramatsu, Kazumasa
N1 - Publisher Copyright:
© 2016 The Japan Society of Applied Physics.
PY - 2016/5
Y1 - 2016/5
N2 - 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.
AB - 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.
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U2 - 10.7567/JJAP.55.05FL02
DO - 10.7567/JJAP.55.05FL02
M3 - Article
AN - SCOPUS:84965081665
VL - 55
JO - Japanese Journal of Applied Physics, Part 1: Regular Papers & Short Notes
JF - Japanese Journal of Applied Physics, Part 1: Regular Papers & Short Notes
SN - 0021-4922
IS - 5
M1 - 05FL02
ER -