MBE Growth and Ultrahigh Temperature Processing of High-Quality AlN Films

1999 ◽  
Vol 587 ◽  
Author(s):  
Z.Y. Fan ◽  
G. Rong ◽  
N. Newman ◽  
David J. Smith ◽  
D. Chandrasekhar

AbstractMolecular beam epitaxial growth of AlN on sapphire and 6H-SiC has been performed utilizing mono-energetic activated nitrogen ion beams (2-80 eV kinetic energies). The growth temperature of AlN in MBE is found to be limited by the sticking coefficient of incident reactants. The combination of elevated growth temperatures (1050-1150°C), high kinetic-energy reactive nitrogen (>40 eV) and post-growth thermal processing (1150-1350°C) produces high-quality AlN thin-f ilms with narrow rocking curve widths (<2 arcmin) and low dislocation densities (<∼3×108cm−2). In contrast, the use of in-situ step anneals during synthesis did not achieve similar quality materials.

1991 ◽  
Vol 220 ◽  
Author(s):  
M. R. Sardela ◽  
W. -X. Ni ◽  
J. O. Ekberg ◽  
J. -E. Sundgren ◽  
G. V. Hansson

ABSTRACTBoron doping, using an elemental boron source during molecular beam epitaxial growth of silicon, has been studied. The boron flux was provided by a high temperature source heated by radiation and electron bombardment. The maximum boron deposition rate used was 1×1012 cm−2 s−1 at an estimated B temperature of 1950 °C. For growth at a substrate temperature of 650 °C, there is very little surface segregation when the doping level is in the range 1×1016-1×1019 cm−3. For very high boron to silicon flux ratio (>7×10−3) there is a strong surface segregation that results in surface accumulation of boron. This initially leads to a 2×2 reconstruction of the Si (100) surface, and further surface segregation during growth results in roughening of the surface due to the creation of (311)-facets. In a separate set of experiments, the surface segregation was studied using in situ Auger electron spectroscopy of predeposited layers of boron that were gradually covered by Si capping layers. Strong and surface coverage dependent surface segregation was observed both in the case of Si (100) and (111) substrates.


2002 ◽  
Vol 722 ◽  
Author(s):  
S. Kiravittaya ◽  
R. Songmuang ◽  
O. G. Schmidt

AbstractEnsembles of homogeneous self-assembled quantum dots (QDs) and nanoholes are fabricated using molecular beam epitaxy in combination with atomically precise in situ etching. Self-assembled InAs QDs with height fluctuations of ±5% were grown using a very low indium growth rate on GaAs (001) substrate. If these dots are capped with GaAs at low temperature, strong room temperature emission at 1.3 νm with a linewidth of 21 meV from the islands is observed. Subsequently, we fabricate homogeneous arrays of nanoholes by in situ etching the GaAs surface of the capped InAs QDs with AsBr3. The depths of the nanoholes can be tuned over a range of 1-6 nm depending on the nominal etching depth and the initial capping layer thickness. We appoint the formation of nanoholes to a pronounced selectivity of the AsBr3 to local strain fields. The holes can be filled with InAs again such that an atomically flat surface is recovered. QDs in the second layer preferentially form at those sites, where the holes were initially created. Growth conditions for the second InAs layer can be chosen in such a way that lateral QD molecules form on a flat surface.


2006 ◽  
Vol 88 (19) ◽  
pp. 191115 ◽  
Author(s):  
Fumitaro Ishikawa ◽  
Michael Höricke ◽  
Uwe Jahn ◽  
Achim Trampert ◽  
Klaus H. Ploog

1991 ◽  
Vol 220 ◽  
Author(s):  
S. Fukatsu ◽  
K. Fujita ◽  
H. Yaguchi ◽  
Y. Shiraki ◽  
R. Ito

Kinetics of Ge segregation during molecular beam epitaxial growth is described. It is shown that the Ge segregation is self-limited in Si epitaxial overlayers due to a high concentration effect when the Ge concentration exceeds 0.01 monolayer (ML). As a result, segregation profiles of Ge are found to decay non-exponentially in the growth direction. This unusual Ge segregation was found to be suppressed with an adlayer of strong segregant, Sb, during the kinetic MBE growth. We develop a novel scheme to realize sharp Si/Ge interfaces with strong segregante. Lower limit of the effective amount of Sb for this was found to be 0.75 ML.


1989 ◽  
Vol 66 (8) ◽  
pp. 3618-3621 ◽  
Author(s):  
J. E. Oh ◽  
P. K. Bhattacharya ◽  
Y. C. Chen ◽  
S. Tsukamoto

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