TY - GEN
T1 - Low propagation loss of atomically-flat surface AlN with low dislocation density for 5-GHz band SAW devices
AU - Uehara, K.
AU - Aota, Y.
AU - Kameda, Suguru
AU - Nakase, H.
AU - Tsubouchi, K.
N1 - Copyright:
Copyright 2008 Elsevier B.V., All rights reserved.
PY - 2005
Y1 - 2005
N2 - Atomically-flat surface (0001) aluminum nitride (AlN) epitaxial films grown by metalorganic chemical vapor deposition (MOCVD) were investigated. To clarify the growth mechanism of the AlN film, dependences between growth rate and process parameters of MOCVD were evaluated. To investigate the relationship between surface roughness and dislocation, three types of dislocation were observed by transmission electron microscopy (TEM). It was found that suppression of the thermal convection was indispensable for growth of atomically-flat surface AlN. From TEM observation, periodical misfit-type dislocation was observed only within the 10-A-thick interface between AlN and sapphire substrate. The density of edge-type dislocation in the AlN surface region was as low as 1010-1011 cm-2. Screw-type dislocation mostly stopped propagating along [0002]AlN within the thickness of 0.5 μm which agreed with the thickness of changing rough surface AlN to atomically-flat surface AlN. It is considered that suppression of screw-type dislocation was contributed to atomically-flat surface AlN.
AB - Atomically-flat surface (0001) aluminum nitride (AlN) epitaxial films grown by metalorganic chemical vapor deposition (MOCVD) were investigated. To clarify the growth mechanism of the AlN film, dependences between growth rate and process parameters of MOCVD were evaluated. To investigate the relationship between surface roughness and dislocation, three types of dislocation were observed by transmission electron microscopy (TEM). It was found that suppression of the thermal convection was indispensable for growth of atomically-flat surface AlN. From TEM observation, periodical misfit-type dislocation was observed only within the 10-A-thick interface between AlN and sapphire substrate. The density of edge-type dislocation in the AlN surface region was as low as 1010-1011 cm-2. Screw-type dislocation mostly stopped propagating along [0002]AlN within the thickness of 0.5 μm which agreed with the thickness of changing rough surface AlN to atomically-flat surface AlN. It is considered that suppression of screw-type dislocation was contributed to atomically-flat surface AlN.
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U2 - 10.1109/ULTSYM.2005.1602891
DO - 10.1109/ULTSYM.2005.1602891
M3 - Conference contribution
AN - SCOPUS:33847139808
SN - 0780393821
SN - 9780780393820
T3 - Proceedings - IEEE Ultrasonics Symposium
SP - 455
EP - 458
BT - 2005 IEEE Ultrasonics Symposium
T2 - 2005 IEEE Ultrasonics Symposium
Y2 - 18 September 2005 through 21 September 2005
ER -