Surface Segregation of Boron During Si-MBE Growth

1991 ◽  
Vol 220 ◽  
Author(s):  
M. R. Sardela ◽  
W. -X. Ni ◽  
J. O. Ekberg ◽  
J. -E. Sundgren ◽  
G. V. Hansson
Keyword(s):  
Surface Segregation ◽  
Flux Ratio ◽  
Mbe Growth ◽  
Molecular Beam Epitaxial ◽  
Elemental Boron ◽  
Strong Surface ◽  
High Boron ◽  
Boron Source ◽  
Molecular Beam Epitaxial Growth

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.

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
Keyword(s):  
High Quality ◽  
Mbe Growth ◽  
Rocking Curve ◽  
Molecular Beam Epitaxial ◽  
Dislocation Densities ◽  
High Kinetic Energy ◽  
Nitrogen Ion ◽  
Ultrahigh Temperature ◽  
Molecular Beam Epitaxial Growth

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.

MBE GROWTH AND CHARACTERIZATION OF Mg-DOPED III-NITRIDES ON SAPPHIRE

2009 ◽  
Vol 19 (01) ◽  
pp. 113-119
Author(s):  
X. CHEN ◽  
K. D. MATTHEWS ◽  
D. HAO ◽  
W. J. SCHAFF ◽  
L. F. EASTMAN ◽  
...  
Keyword(s):  
Hole Concentration ◽  
Mbe Growth ◽  
Molecular Beam Epitaxial ◽  
Strong Surface ◽  
Photo Response ◽  
Molecular Beam Epitaxial Growth ◽  
P Type ◽  
Iv Curves ◽  
Mg Doped

Plasma-assisted molecular beam epitaxial growth of Mg -doped GaN and InGaN on a sapphire substrate is investigated in this study. Electrical characteristics of p -type GaN strongly depend on the flux of Mg acceptors and the growth temperature. Only the intermediate range of Mg fluxes (beam equivalent pressures near 1×10-9T) produce p -type GaN with good electrical properties, and a maximum hole concentration of 3.5 × 1018 cm-3 is obtained with a Hall mobility of 2.1 cm2/V·s. Due to the strong surface accumulation of electrons, Hall measurements do not indicate p -type polarity for In fraction beyond 11%. In contrast, hot probe measurements show that p -polarity can be measured for the entire range of Mg -doped In mole fractions. Electroluminescence also indicates p -polarity for Ga -rich mole fractions. In x Ga1- x N p - n homojunctions are fabricated and tested. All GaN devices show low series resistance (0.03 ohm-cm2) and insignificant parasitic leakage. IV curves of all three InGaN homojunctions show rectifying characteristics under dark conditions and photo-response under outdoor sunlight, indicating the existence of holes in InGaN with up to 40% In content.

scholarly journals Beating in the RHEED Intensity Oscillations during Surfactant Mediated GaAs Molecular Beam Epitaxy: Process Physics and Modeling

VLSI Design ◽  
1998 ◽  
Vol 6 (1-4) ◽  
pp. 405-408
Author(s):  
Vamsee K. Pamula ◽  
R. Venkat
Keyword(s):  
Molecular Beam ◽  
Flux Ratio ◽  
High Energy ◽  
Equation Model ◽  
High Energy Electron ◽  
Fixed Temperature ◽  
Mbe Growth ◽  
Molecular Beam Epitaxial ◽  
Monolayer Coverage ◽  
Period Of Oscillation

In a recent work, beating in the reflection high energy electron diffraction (RHEED) intensity oscillations were observed during molecular beam epitaxial (MBE) growth of GaAs with Sn as a surfactant. The strength of beating is found to be dependent on the Sn submonolayer coverage with strong beating observed for 0.4 monolayer coverage. For a fixed temperature and flux ratio (Ga to As), the period of oscillation decreases with increasing Sn coverage. In this work, we have developed a rate equation model of growth to investigate this phenomenon. In our model, the GaAs covered by the Sn is assumed to grow at a faster rate compared to the GaAs not covered by Sn. Assuming that the electron beams reflected from the Sn covered surface and the rest of the surface are incoherent, the results of the dependence of the RHEED oscillations on Sn submonolayer coverages for various Sn coverages were obtained and compared with experimental data and the agreement is good.

Self-assembled quantum dots and nanoholes by molecular beam epitaxial growth and atomically precise in situ etching

2002 ◽  
Vol 722 ◽  
Author(s):  
S. Kiravittaya ◽  
R. Songmuang ◽  
O. G. Schmidt
Keyword(s):  
Quantum Dots ◽  
Molecular Beam ◽  
Flat Surface ◽  
Local Strain ◽  
Growth Conditions ◽  
Etching Depth ◽  
Molecular Beam Epitaxial ◽  
Self Assembled ◽  
Molecular Beam Epitaxial Growth

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.

Kinetics of Ge Segregation in the Presence of Sb During Molecular Beam Epitaxy

1991 ◽  
Vol 220 ◽  
Author(s):  
S. Fukatsu ◽  
K. Fujita ◽  
H. Yaguchi ◽  
Y. Shiraki ◽  
R. Ito
Keyword(s):  
Molecular Beam Epitaxy ◽  
Epitaxial Growth ◽  
Lower Limit ◽  
Molecular Beam ◽  
Growth Direction ◽  
High Concentration ◽  
Mbe Growth ◽  
Molecular Beam Epitaxial ◽  
Molecular Beam Epitaxial Growth ◽  
Kinetics Of

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.

Self‐limitation in the surface segregation of Ge atoms during Si molecular beam epitaxial growth

1991 ◽  
Vol 59 (17) ◽  
pp. 2103-2105 ◽  
Author(s):  
S. Fukatsu ◽  
K. Fujita ◽  
H. Yaguchi ◽  
Y. Shiraki ◽  
R. Ito
Keyword(s):  
Epitaxial Growth ◽  
Molecular Beam ◽  
Surface Segregation ◽  
Molecular Beam Epitaxial ◽  
Molecular Beam Epitaxial Growth

Controlled Growth and Characterization of Non-tapered InN Nanowires on Si(111) Substrates by Molecular Beam Epitaxy

2009 ◽  
Vol 1178 ◽  
Author(s):  
Yi-Lu Chang ◽  
Arya Fatehi ◽  
Feng Li ◽  
Zetian Mi
Keyword(s):  
Molecular Beam Epitaxy ◽  
Epitaxial Growth ◽  
Room Temperature ◽  
Molecular Beam ◽  
Stacking Faults ◽  
Seeding Layer ◽  
Mbe Growth ◽  
Molecular Beam Epitaxial

AbstractWe have performed a detailed investigation of the molecular beam epitaxial (MBE) growth and characterization of InN nanowires spontaneously formed on Si(111) substrates under nitrogen rich conditions. Controlled epitaxial growth of InN nanowires (NWs) has been demonstrated by using an in situ deposited thin (˜ 0.5 nm) In seeding layer prior to the initiation of growth. By applying this technique, we have achieved non-tapered epitaxial InN NWs that are relatively free of dislocations and stacking faults. Such InN NW ensembles display strong photoluminescence (PL) at room temperature and considerably reduced spectral broadening, with very narrow spectral linewidths of 22 and 40 meV at 77 K and 300 K, respectively.

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