Reduction of threading dislocations in migration enhanced epitaxy grown GaN with N-polarity by use of AlN multiple interlayer

• Published in: Journal of crystal growth 2001-09, Vol.230 (3), p.387-391
• Main Authors: Kusakabe, Kazuhide, Kishino, Katsumi, Kikuchi, Akihiko, Yamada, Takayuki, Sugihara, Daisuke, Nakamura, Shinich
• Format: Article
• Language: English
• Subjects: A3. Migration enhanced epitaxy; A3. Molecular beam epitaxy; B1. Nitrides; B2. Semiconducting III-V materials; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Defects and impurities: doping, implantation, distribution, concentration, etc; Exact sciences and technology; Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Molecular, atomic, ion, and chemical beam epitaxy; Physics; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Thin film structure and morphology
• ISSN: 0022-0248; 1873-5002
• DOI: 10.1016/S0022-0248(01)01248-9

High quality GaN layer was obtained by insertion of high temperature grown AlN multiple intermediate layers with migration enhanced epitaxy method by the RF-plasma assisted molecular beam epitaxy on (0 0 01) sapphire substrates. The propagating behaviors of dislocations were studied, using a transmission electron microscope. The results show that the edge dislocations were filtered at the AlN/GaN interfaces. The bending propagation of threading dislocations in GaN above AlN interlayers was confirmed. Thereby, further reduction of dislocations was achieved. Dislocation density being reduced, the drastic increase of electron mobility to 668 cm 2/V s was obtained at the carrier density of 9.5×10 16 cm −3 in Si doped GaN layer.