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Growth of N‐polarity InN by ArF‐laser assisted MOVPE
Author(s) -
Yamamoto A.,
Kasashima K.,
Miyanishi M.,
Hashimoto A.
Publication year - 2006
Publication title -
physica status solidi (a)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 104
eISSN - 1862-6319
pISSN - 1862-6300
DOI - 10.1002/pssa.200563524
Subject(s) - excimer laser , metalorganic vapour phase epitaxy , materials science , substrate (aquarium) , sapphire , etching (microfabrication) , laser , layer (electronics) , optoelectronics , analytical chemistry (journal) , epitaxy , nanotechnology , optics , chemistry , chromatography , oceanography , physics , geology
In this paper, the employment of the ArF excimer‐laser assisted nitridation of sapphire substrate is studied in the ArF‐laser assisted MOVPE (la‐MOVPE) of InN. An ArF excimer laser with an energy 50 mJ/pulse and a repetition rate 20 Hz is introduced parallel to the substrate surface. The surface morphology of InN film grown on α‐Al 2 O 3 (0001) is found to be markedly dependent on the nitridation conditions for the sapphire substrate. When no nitridation is made, the surface of grown InN film is very rough and many In droplets are found on it. A film with a mixture of rough‐surface region with In droplets and smooth‐surface region is grown on the thermally‐nitrided substrate (1000 °C for 30 min). By employing the ArF‐laser irradiation to the NH 3 flow during the substrate nitridation at 1000 °C for 30 min (la‐nitridation), a smooth surface region is expanded to the entire surface of film. The smooth surface is found to be stable at growth temperature higher than 700 °C. The KOH etching of grown films reveals that the smooth surface has 5–10 time higher etching rate than the rough one. From these facts, it is concluded that the film with the smooth surface has N‐polarity. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)