The Use of Tertiarybutylphosphine and Tertiarybutylarsine for the Metalorganic Molecular Beam Epitaxial Growth of Resonant Tunneung Devices

1991 ◽  
Vol 240 ◽  
Author(s):  
E. A. Beam ◽  
A. C. Seabaugh
Keyword(s):  
Resonant Tunneling ◽  
Growth Conditions ◽  
Structural Quality ◽  
Cross Sectional ◽  
Molecular Beam Epitaxial ◽  
Tunneling Diode ◽  
Transmission Electron ◽  
Molecular Beam Epitaxial Growth ◽  
First Time ◽  
Lattice Matched

ABSTRACTWe report on the use of thermally-cracked tertiarybutylphosphine (TBP) and tertiarybutylarsine (TBA) with elemental Ga, In, and Al sources for the MOMBE growth of InP-based resonant tunneling diode (RTD) and resonant tunneling bipolar transistor (RTBT) structures. We have systematically examined the effects of growth conditions and heterostructure modifications on the InP/lnGaAs RTD including the use of pseudomorphic (InGa)P barriers and, in addition, explored for the first time, InP quantum well RTDs using both AlAs and InGaP barriers. Cross-sectional transmission electron microscopy has been used to correlate the structural quality with the electrical characteristics for both lattice-matched and pseudomorphic layers composed of InAs, AlAs, and InGaP. We also demonstrate the first use of mixed InP/lnGaAs and AlAs/lnGaAs heterojunctions in the RTBT. These transistors exhibit room temperature negative transconductance and a peak-to-valley current ratio of 35, the highest yet observed In the RTBT.

Molecular Beam Epitaxial Growth of (Al,Ga)As Tilted Superlattices on Vicinal GaAs (110)

1991 ◽  
Vol 237 ◽  
Author(s):  
Mohan Krishnamurthy ◽  
M. Wassermeier ◽  
H. Weman ◽  
J. L. Merz ◽  
P. M. Petroffa
Keyword(s):  
Quantum Wells ◽  
Molecular Beam ◽  
Growth Conditions ◽  
Vicinal Surface ◽  
Vicinal Surfaces ◽  
Island Growth ◽  
Quantum Well Structures ◽  
Molecular Beam Epitaxial ◽  
Transmission Electron ◽  
Molecular Beam Epitaxial Growth

ABSTRACTA study of the molecular beam epitaxial (MBE) growth on singular and vicinal (110) surfaces of GaAs is presented. Quantum well structures and tilted superlattices (TSL) were grown on substrates misoriented 0.5°-2° towards the nearest [010] and [111]A azimuths at growth temperatures ranging from 450° C to 600° C under different growth conditions. The structures were characterized by Nomarski optical microscopy, transmission electron microscopy (TEM) and photoluminescence (PL) spectroscopy.Two types of faceting were observed on the surfaces. The structures grown at temperatures above 540°C and As beam fluxes below l×10-5 torr showed V-shaped facets pointing in the [001] direction and are attributed to As deficient island growth. Lower temperatures and higher As beam fluxes lead to surfaces with microfacets that are elongated along the respective step directions on the vicinal surface and are due to step bunching during growth. Their density and height decrease with decreasing vicinal angle and they disappear on the singular (110) surface. The photoluminescence of the GaAs quantum wells grown on these samples is redshifted with respect to that of the quantum wells grown on the flat surface. This is being ascribed to the fact that on the vicinal surface, the recombination takes place at the facets where the quantum wells are wider.The contrast in the TEM images of the TSL show for the samples misoriented towards [010] that the lateral segregation to the step edges on this surface is appreciable. The TSL spacing and the tilt however show that during growth the vicinal surfaces tend towards a surface with smaller miscut.

Conducting (Si-Doped) Aluminum Nitride Epitaxial Films Grown by Molecular Beam Epitaxy

1999 ◽  
Vol 572 ◽  
Author(s):  
J. G. Kim ◽  
Madhu Moorthy ◽  
R. M. Park
Keyword(s):  
Growth Temperature ◽  
Molecular Beam ◽  
Growth Parameters ◽  
Growth Conditions ◽  
Preparation Methods ◽  
Molecular Beam Epitaxial ◽  
Si Doped ◽  
Molecular Beam Epitaxial Growth ◽  
First Time ◽  
Selection Of

ABSTRACTAs a member of the III-V nitride semiconductor family, AlN, which has a direct energygap of 6.2eV, has received much attention as a promising material for many applications. However, despite the promising attributes of AlN for various semiconductor devices, research on AlN has been limited and n-type conducting AlN has not been reported. The objective of this research was to understand the factors impacting the conductivity of AlN and to control the conductivity of this material through intentional doping. Prior to the intentional doping study, growth of undoped AlN epilayers was investigated. Through careful selection of substrate preparation methods and growth parameters, relatively low-temperature molecular beam epitaxial growth of AlN films was established which resulted in insulating material. Intentional Si doping during epilayer growth was found to result in conducting films under specific growth conditions. Above a growth temperature of 900°C, AlN films were insulating, however, below a growth temperature of 900°C, the AlN films were conducting. The magnitude of the conductivity and the growth temperature range over which conducting AlN films could be grown were strongly influenced by the presence of a Ga flux during growth. For instance, conducting, Si-doped, AlN films were grown at a growth temperature of 940°C in the presence of a Ga flux while the films were insulating when grown in the absence of a Ga flux at this particular growth temperature. Also, by appropriate selection of the growth parameters, epilayers with n-type conductivity values as large as 0.2 Ω−1 cm−1 for AlN and 17 Ω−1cm−1 for Al0.75Ga0.25N were grown in this work for the first time.

Structural studies of HgCdTe grown by MOCVD on lattice-matched substrates

1990 ◽  
Vol 5 (7) ◽  
pp. 1475-1479 ◽  
Author(s):  
M. J. Bevan ◽  
J. Greggi ◽  
N. J. Doyle
Keyword(s):  
Chemical Vapor ◽  
Structural Quality ◽  
Organic Chemical ◽  
Double Crystal ◽  
Cross Sectional ◽  
Transmission Electron ◽  
Compositional Uniformity ◽  
Metal Organic ◽  
Interdiffused Multilayer Process ◽  
Lattice Matched

Improved structural quality Hg1−xCdxTe epitaxial films have been grown by metal organic chemical vapor deposition (MOCVD) using the interdiffused multilayer process (IMP) on lattice-matched CdZnTe substrates at temperatures above 400°C with diethyltelluride. Double-crystal rocking curve data with values as low as 25 arcsec correlated with cross-sectional transmission electron micrographs. The process of growing alternate layers of HgTe/CdTe for improved compositional uniformity, and the inherent mismatch, was not detrimental to the structural quality, which was limited by that of the substrate.

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.

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.

MBE Growth of Low Dislocation and High Mobility GaAs-on-Si

1986 ◽  
Vol 67 ◽  
Author(s):  
Jhang Woo Lee
Keyword(s):  
Layer Structure ◽  
High Mobility ◽  
Gaas Layer ◽  
Buffer Layers ◽  
Misfit Dislocations ◽  
Si Substrates ◽  
Molecular Beam Epitaxial ◽  
Transmission Electron ◽  
Low Dislocation Density ◽  
Molecular Beam Epitaxial Growth

ABSTRACTData is presented on the optimization of several molecular beam epitaxial growth processes to provide low dislocation density and high mobility GaAs single crystals on (100) Si wafers. The substrate tilt angle, the growth temperature, and the first buffer layer structure, were investigated Tor this purpose. Using Hall measurements the GaAs layers grown on 2 or 3-degree tilt (100) Si showed consistently high mobilities which are equivalent to the homoepitaxial GaAs mobility. Transmission electron microscopy (TEM) revealed that on tilted (100) Si substrates most of the misfit dislocations were confined within the first 50 Å GaAs layer by forming a type of edge dislocation at the Si surface step edges. Also low temperature grown buffer layers always gave better morphologies and lower etch pit densities while keeping the high mobilities on overgrown GaAs layers.

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