Berlin 2008 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 47: GaN: preparation and characterization I
HL 47.11: Talk
Thursday, February 28, 2008, 16:45–17:00, EW 202
MOVPE of m-plane InGaN/GaN buffer and LED structures on LiAlO2 — Hannes Behmenburg1, Tzu-Chi Wen2, Yilmaz Dikme1, Christof Mauder2, Lars Khoshroo2, Mitch Chou3, Mikalai Rzheutskii4, Evgenii Lutsenko4, Gennadii Yablonskii4, Joachim Woitok5, Holger Kalisch2, Rolf Jansen2, and •Michael Heuken1,2 — 1AIXTRON AG, Aachen, Germany — 2Electrom. Theory, RWTH Aachen, Germany — 3Mat. Sci. & Opto-Elect. Eng., Sun Yat-Sen Univ., Taiwan — 4Inst. of Phys., NASB, Minsk, Belarus — 5PANalytical B.V., Almelo, The Netherlands
M-plane GaN growth on LiAlO2(100) is one possibility to deposit non-polar material and leads to a more efficient recombination in MQW structure. A short in-situ nitridation in a nitrogen/ammonia atmosphere as the first step is essential for the deposition of GaN in the m-plane mode. The surface was sealed with a thin Mg-doped InGaN layer. A 220 nm thick GaN:Mg and a 500 nm thick GaN layer to protect the sensitive substrate grown under H2 atmosphere complete the investigated buffer. In 2Theta/Omega scans only m-plane GaN was detected, and rocking curves of the symmetric (1-100) reflex revealed an improvement in quality with increasing thickness of the InGaN:Mg layer up to 100 nm. Above this critical thickness, the line width deteriorated. The same trend was observed by AFM measurements which showed a minimum surface roughness of 11.4 nm root mean square. Blue InGaN LED structures on such buffers showed photoluminescence wavelengths which were independent of excitation intensity and exhibited a high degree of polarization.