Superiority of an AlN Intermediate Layer for Heteroepitaxy of Hexagonal GaN

• Published in: Japanese Journal of Applied Physics Vol. 39; no. 8R; pp. 4869 - 4874
• Main Authors: Sasaki, Masahiro, Nakayama, Tomoo, Shimoyama, Norio, Suemasu, Takashi, Hasegawa, Fumio
• Format: Journal Article
• Language: English
• Published: 2000
• ISSN: 0021-4922; 1347-4065
• DOI: 10.1143/JJAP.39.4869

The superiority of AlN as an intermediate layer during heteroepitaxy of GaN on GaAs substrates is demonstrated on the basis of growth rates, surface reactivity and crystallography. Although GaN growth on GaAs using monomethyl-hydrazine (MMHy) as a nitrogen source shows a long lag time to start growth, this lag time disappears upon the insertion of an AlN intermediate layer. Based on mass spectrometric analysis, these growth behaviors are attributed to the decomposition of MMHy which is enhanced by the Al source injection onto GaAs surfaces. The growth mechanism is explained within a framework of simple bond behavior. Further, it is confirmed by pole figure X-ray diffraction observations that a single phase hexagonal GaN layer is grown on GaAs(111)B substrates when the AlN intermediate layer is inserted, while a cubic phase is included in the GaN grown directly on the GaAs(111)B surface.