AlN buffer layer growth for GaN epitaxy on (111) Si: Al or N first?

AlN is generally used as buffer layer for the epitaxial growth of GaN on Si(111) substrate. In this work, we specifically address the relationship between the way the AlN growth is initiated on the Si(111) surface and the overall properties of the final GaN epitaxial layer. The growth is performed b...

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Bibliographic Details
Published inJournal of crystal growth Vol. 311; no. 12; pp. 3278 - 3284
Main Authors Le Louarn, A., Vézian, S., Semond, F., Massies, J.
Format Journal Article
LanguageEnglish
Published Elsevier B.V 01.06.2009
Subjects
A1. RHEED
A3. MBE
B1. Nitrides
A1. RHEED
B1. Nitrides
61.05.jh
A3. MBE
81.15.Hi
68.37.Ef
81.05.Ea
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Summary:AlN is generally used as buffer layer for the epitaxial growth of GaN on Si(111) substrate. In this work, we specifically address the relationship between the way the AlN growth is initiated on the Si(111) surface and the overall properties of the final GaN epitaxial layer. The growth is performed by molecular beam epitaxy with ammonia (NH3) as nitrogen source. Two procedures have been compared: exposing the Si surface first to NH3 or Al. The AlN nucleation is followed in real-time by reflection high-energy electron diffraction and critical stages are also investigated in real space using scanning tunnelling microscopy and transmission electron microscopy. Atomic force microscopy, X-ray diffraction and photoluminescence are also used to assess the properties of the final GaN epitaxial layer. It is shown that best results in terms of GaN overall properties are obtained when the growth is initiated by exposing the Si(111) surface to NH3 first. This is mainly due to the fact that almost an order of magnitude decrease of the dislocation density is obtained.
Bibliography:ObjectType-Article-2
SourceType-Scholarly Journals-1
ObjectType-Feature-1
content type line 23
ISSN:0022-0248
1873-5002
DOI:10.1016/j.jcrysgro.2009.04.001