Sticking and Desorption Coefficients of As4 and As2 During Group V and Group III Controlled MBE Growth

1992 ◽  
Vol 263 ◽  
Author(s):  
Rouel Fernandez
Keyword(s):  
Activation Energy ◽  
Flux Ratio ◽  
Growth Conditions ◽  
High Energy ◽  
Controlled Growth ◽  
Sticking Coefficient ◽  
Group V ◽  
Mbe Growth ◽  
Group Iii ◽  
Sticking Coefficients

ABSTRACTReflection High Energy Electron Diffraction (RHEED) oscillations under arsenic and gallium-controlled Molecular Beam Epitaxy (MBE) growth conditions have been used to measure the sticking and desorption coefficients of As2 and As4. The coefficients are obtained from measurements of the arsenic incorporation rates. Comparisons are made with measurements obtained from desorption rates using modulated beam mass spectroscopy. The transition from gallium to arsenic-controlled growth is observed to occur after excess gallium atoms accumulate on the surface. The maximum intrinsic arsenic sticking coefficients occur when the maximum number of gallium atoms can be incorporated for a given arsenic flux. The intrinsic maximum arsenic sticking coefficients are found to be 0.75 and 0.50 for As2 and As4, respectively. During galliumcontrolled growth, the arsenic sticking coefficients are independent of substrate temperature as long as the sticking coefficient of gallium is equal to one. However, a temperature dependent maximum gallium-controlled arsenic sticking coefficient exists. It can be measured by the maximum Ga to As4 flux ratio that produces specular film surfaces. During gallium-controlled growth, the Ga to As flux ratios are shown to be equal to the gallium-controlled arsenic sticking coefficients. The activation energy for arsenic desorption during arsenic-controlled growth conditions was measured as -0.50 eV for independent As4 and As2 incident fluxes. During gallium-controlled growth with incident As4 fluxes, an activation energy for arsenic desorption of -0.70 eV was measured for the maximum gallium-controlled arsenic sticking coefficients.

Temperature Dependent Quasi-Periodic Facetting of AlAs Grown by MBE on (100) GaAs Substrates

1993 ◽  
Vol 312 ◽  
Author(s):  
Richard Mirin ◽  
Mohan Krishnamurthy ◽  
James Ibbetson ◽  
Arthur Gossard ◽  
John English ◽  
...  
Keyword(s):  
Growth Conditions ◽  
High Energy ◽  
High Energy Electron ◽  
Temperature Dependent ◽  
Cross Sectional ◽  
Mbe Growth ◽  
Atomic Force ◽  
Gaas Substrates ◽  
Transmission Electron ◽  
Facet Formation

AbstractHigh temperature (≥ 650°C) MBE growth of AlAs and AlAs/GaAs superlattices on (100) GaAs is shown to lead to quasi-periodic facetting. We demonstrate that the facetting is only due to the AlAs layers, and growth of GaAs on top of the facets replanarizes the surface. We show that the roughness between the AlAs and GaAs layers increases with increasing number of periods in the superlattice. The roughness increases to form distinct facets, which rapidly grow at the expense of the (100) surface. Within a few periods of the initial facet formation, the (100) surface has disappeared and only the facet planes are visible in cross-sectional transmission electron micrographs. At this point, the reflection high-energy electron diffraction pattern is spotty, and the specular spot is a distinct chevron. We also show that the facetting becomes more pronounced as the substrate temperature is increased from 620°C to 710°C. Atomic force micrographs show that the valleys enclosed by the facets can be several microns long, but they may also be only several nanometers long, depending on the growth conditions.

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.

Study of As and P Incorporation Behavior in GaAsP by Gas-Source Molecular-Beam Epitaxy

1991 ◽  
Vol 222 ◽  
Author(s):  
B. W. Liang ◽  
H. Q. Hou ◽  
C. W. Tu
Keyword(s):  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
High Energy ◽  
Ex Situ ◽  
Limited Growth ◽  
Group V ◽  
Group Iii ◽  
Gas Source ◽  
Simple Kinetic Model

ABSTRACTA simple kinetic model has been developed to explain the agreement between in situ and ex situ determination of phosphorus composition in GaAs1−xPx (x < 0.4) epilayers grown on GaAs (001) by gas-source molecular-beam epitaxy (GSMBE). The in situ determination is by monitoring the intensity oscillations of reflection high-energy-electron diffraction during group-V-limited growth, and the ex situ determination is by x-ray rocking curve measurement of GaAs1−xPx/GaAs strained-layer superlattices grown under group-III-limited growth condition.

Determination of as Sticking Coefficients Using Reflection high Energy Electron Diffraction Intensity Oscillations on GaAs

1989 ◽  
Vol 145 ◽  
Author(s):  
Robert Chow ◽  
Rouel Fernandez
Keyword(s):  
Substrate Temperature ◽  
High Energy ◽  
Incorporation Rate ◽  
Sticking Coefficient ◽  
Diffraction Intensity ◽  
Arrhenius Dependence ◽  
As Species ◽  
Substrate Temperatures ◽  
Sticking Coefficients

AbstractRHEED intensity oscillations were used to investigate As-controlled incorporation rates. The measurements were made under Ga accumulation at the surface of the substrate, and at fluxes and substrate temperatures common for 1.0 micron/hr GaAs growth. The results between the dimer and tetramer As species were compared. The transition between Ga and As controlled incorporation rates was constant within 2.5°C for a constant As flux and was independent of the substrate temperature. Also, the As-controlled incorporation rate curves shows two regions as the substrate temperature increases. At low substrate temperatures, the As incorporation rate is substrate temperature independent. Then at higher substrate temperatures, the As incorporation rate has an arrhenius dependence with a positive activation energy. An interpretation of these results is possible by assigning the maximum sticking coefficient of the tetramer to the region where the As incorporation rate is independent of substrate temperature. This assignment allows one to derive the As (dimers and tetramers) sticking coefficient dependence with substrate temperature. The dimer sticking coefficients are greater that the tetramer sticking coefficients for a given substrate temperature and As flux, and the maximum sticking coefficient of the As dimer was determined to be 0.8 in these experiments.

Adsorption and Desorption Kinetics for Chlorosilanes on Si(111) 7×7

1990 ◽  
Vol 204 ◽  
Author(s):  
P. Gupta ◽  
P.A. Coon ◽  
B.G. Koehler ◽  
M.L. Wise ◽  
S.M. George
Keyword(s):  
Activation Energy ◽  
Surface Coverage ◽  
Temperature Programmed Desorption ◽  
Desorption Kinetics ◽  
Sticking Coefficient ◽  
Temperature Dependent ◽  
Adsorption And Desorption ◽  
Desorption Activation Energy ◽  
Temperature Programmed ◽  
Sticking Coefficients

ABSTRACTThe adsorption and desorption kinetics for SiCl4 and SiCl2H2 on Si(111) 7×7 were studied using laser-induced thermal desorption (LITD) and temperature programmed desorption (TPD) techniques. Both LITD and TPD experiments monitored SiCl2 as the main desorption product at 950 K at all coverages of SiCl4 and SiCl2H2 on Si(111) 7×7.HC1 desorption at 850 K and H2 desorption at 810 K were also observed following SiCl2H2 adsorption. Isothermal LITD measurements of SiCl4 and SiCl2H2) adsorption on Si(111) 7×7 revealed that the initial reactive sticking coefficient decreased with increasing surface temperature for both molecules. The temperature-dependent sticking coefficients were consistent with precursor-mediated adsorption kinetics. Isothermal LITD studies of SiC12 desorption revealed second-order SiCl2 desorption kinetics. The desorption kinetics were characterizedby a desorption activation energy of Ed = 67 kcal/mol and a preexponential of vd = 3.2 cm2/s. TPD studies observed that the HCI desorption yield decreased relative to H2 and SiCl2 desorption as a function of surface coverage following SiCl2H2 exposure. These results indicate that when more hydrogen desorbs as H2 at higher coverages, The remaining chlorine is forced to desorb as SiCl 2.

The Effect of Substrate Orientation on the Properties of (Ga, Al)As Grown by Gas Source Molecular Beam Epitaxy

1988 ◽  
Vol 144 ◽  
Author(s):  
A. Sandhu ◽  
T. FUJII ◽  
H. Ando ◽  
H. Ishikawa ◽  
E. Miyauchi
Keyword(s):  
Growth Rate ◽  
Growth Conditions ◽  
Group V ◽  
Group Iii ◽  
Al Content ◽  
Gas Source ◽  
Compensation Ratio ◽  
Potential Applications ◽  
Si Doped ◽  
Gas Source Mbe

ABSTRACTWe have carried out the first systemmatic investigation on the effect of substrate temperature and arsenic partial pressure on the morphology, growth rate, and compensation ratio of Si-doped GaAs, and the Al content of AlxGa1−xAs grown on just-cut (100), (110), (111)A&B, (311)A&B orientated GaAs substrates by gas source MBE (GSMBE). Triethylgallium ( TEG, Ga(C2H5)3 ) and triethylaluminium ( TEA, Al(C2H5)3 ) were used as group III sources, and solid arsenic ( As4 ) and silicon as a group V and IV sources, respectively. The best GaAs mophology was obtained at relatively high temperatures and arsenic pressures. The A orientations were identified as ‘fast surfaces,’ with the GaAs growth rate being comparable to the (100) orientation. The B orientations were identified as ‘slow surfaces,’ with the GaAs growth rate being much less (approximately 50% for the (111)B orientation ) than on the (100) orientation. The least compensated Si-doped GaAs was grown on the (311)A orientated substrate. The Al content, x, (nominally x=0.27 for (100)) of AlxGas1−xAs grown on (110), (111)A&B, was less than 0.05 and not affected by the growth conditions. The Al content of epilayers grown on (311)A&B ranged between x=0.1 to 0.27, strongly depending on the growth temperature.These results show that using GSMBE we can selectively modifying a large range of (Ga,Al)As crystal properties. Potential applications include the selective growth and realisation of ultra-fine and planar structures and devices.

Arsenic Incorporation in InP Epilayers and Arsenide/InP Heterostructures Grown by Chemical Beam Epitaxy

1994 ◽  
Vol 340 ◽  
Author(s):  
V. Rossignol ◽  
A. H. Bensaoula ◽  
A. Freundlich ◽  
A. Bensaoula ◽  
G. Neu
Keyword(s):  
Quantum Wells ◽  
Flux Ratio ◽  
Optimal Growth ◽  
Growth Conditions ◽  
Chemical Beam Epitaxy ◽  
X Ray Diffraction ◽  
Group V ◽  
Low Levels ◽  
Diffraction Patterns ◽  
Arsenic Incorporation

ABSTRACTLow levels of arsenic contamination have been previously reported (∼0.01%) in CBE grown InP by different groups. The level of As incorporation in InP is usually enhanced when arsenide(InGaAs, InAsP) / InP heterostructures are grown.In this work, optimal growth conditions to minimize the non-intentional As contamination during the growth of these heterostructures are discussed. The red shift of band-edge excitons in the low temperature photoluminescence spectra as well as the analysis of high resolution X-ray diffraction patterns of InAsP/InP multi-quantum wells suggest the presence of As in InP barriers. This contamination is consistent with the ratio of As/P partial pressure (As residual in the chamber: 10-9-10-8 Torr) and the As/P incorporation rates. We have studied the influence of the growth temperature, the group-V/III flux ratio and the growth rate on the level of the As incorporation.

Molecular Beam Epitaxy of II/VI Compounds for Blue/Green Laser Diodes

1994 ◽  
Vol 340 ◽  
Author(s):  
J.M. Gaines
Keyword(s):  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Laser Diodes ◽  
High Energy ◽  
Green Laser ◽  
Mbe Growth ◽  
Lattice Matching ◽  
Migration Enhanced Epitaxy ◽  
Sticking Coefficients

ABSTRACTThe growth of I1/VI epitaxial layers by molecular beam epitaxy (MBE) for blue/green lasers is described. To elucidate the issues in the growth of II/VI materials, the differences between II/V and II/VI MBE growth are addressed, including factors such as: substrates, molecular beam sources, lattice matching, sticking coefficients, and surface diffusion. Results of reflection high-energy diffraction (RHEED) oscillation measurements are presented. RHEED oscillations have proven to be a valuable in-situ tool for controlling certain aspects of 1I/VI MBE growth, such as ZnSySe1-y composition, Zn1-xMgxSe composition, and the growth rate of ZnSe during migration-enhanced epitaxy.

scholarly journals The Importance of In Situ Monitors in the Preparation of Layered Oxide Heterostructures by Reactive MBE

2000 ◽  
Vol 619 ◽  
Author(s):  
D.G. Schlom ◽  
J.H. Haenit ◽  
C.D. Theis ◽  
W. Tian ◽  
X.Q. Pan ◽  
...  
Keyword(s):  
Growth Conditions ◽  
High Energy ◽  
Controlled Growth ◽  
Oxide Heterostructures ◽  
Layered Oxide ◽  
Composition Control ◽  
Force Microscopy ◽  
Transmission Electron ◽  
New Compounds

ABSTRACTUsing a variety of in situ monitors and when possible adsorption-controlled growth conditions, layered oxide heterostructures including new compounds and metastable superlattices have been grown by reactive molecular beam epitaxy (MBE). The heteroepitaxial layers grown include Bi4Ti3 O12—SrTiO3 and Bi4Ti3O12—PbTiO3 Aurivillius phases, Srn+1TinO3n+1 Ruddlesden-Popper phases, and metastable PbTiO3 / SrTiO3 and BaTiO3 / SrTiO3 superlattices. Accurate composition control is key to the controlled growth of such structures, and to this end combinations of reflection high-energy electron diffraction (RHEED), atomic absorption spectroscopy (AA), a quartz crystal microbalance (QCM), and adsorption-controlled growth conditions were employed during growth. The structural perfection of the films has been investigated using in situ RHEED, four-circle x-ray diffraction, atomic force microscopy (AFM), and high-resolution transmission electron microscopy (TEM).

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