bluuebunny/crossref_metadata_2025_split huggingface dataset:
Determination of as Sticking Coefficients Using Reflection high Energy Electron Diffraction Intensity Oscillations on GaAs
Authors: Chow Robert , Fernandez Rouel 
Published: March 2011

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.
Element III Segregation During Mocvd Growth on Structured Substrates
Authors: Menu Eric P. , Dzurko Kenneth M. , Dapkus P. Daniel 
Published: March 2011

AbstractThe crystal habits of GaAs and GaAlAs grown on structured substrates by Metalorganic Chemical Vapor Deposition (MOCVD) have been investigated. The growth behavior was delineated by depositing alternating thin layers of AlGaAs and GaAs over grooves and mesas. A strong temperature dependence of facet growth rate and an anisotropy of Al composition with facet orientation are observed. This latter effect so far undocumented in MOCVD has been analysed by Auger Electron Spectroscopy performed on cleaved cross-sections. BCF theory has been used to extract quantitative microscopic data. These observations demonstrate the importance of surface effects and provide an insight into MOCVD growth mechanisms.
Production of GaAs and InP Based Heterostructures
Authors: Jorgensen H. , Schreiner R. K. , Deschler M. 
Published: March 2011

AbstractThe complete requested range of epitaxial deposition from one monolayer to tens of microns is available integrating LP-MOVPE and LP-VPE into wafer fabrication. Uniformity across 2 inch wafers for thickness, composition, and doping show a variation of less than 2 %. Electrical properties of the 1014 cm−3range and less for background doping, carrier mobilities of 210,000 cm2/Vs for AIGaAs and 190,000 cm2/Vs for GalnAs, both HEMT structures, are achieved. FWHM of 3.4 meV and 18.6 meV for 10 nm and 2 nm GaInAsP wells have been measured. GaAsP layers including a “graded” layer reveal FWHM of 15 nm. A new model for the understanding of high growth rates in the hydride system is demonstrated.
Atomic Layer Epitaxy of GaAs and InAs
Authors: Jeong Weon G. , Menu E.P. , Dapkus P.D. 
Published: March 2011

AbstractThe saturation behavior of growth of GaAs and InAs by atomic layer epitaxy is studied. The growth rate is found to be strongly dependent on alkyl exposure time for the same total alkyl exposure per cycle. The longer the exposure time, the higher the saturated growth rate is. For short exposure, the growth rate saturates to a value less than one monolayer (ML)/cycle. Strong saturation of the growth rate to one ML/cycle is achieved for InAs at a growth temperature of 340°C with 3 sec of trimethylindium exposure. For GaAs, saturation of the growth rate to one ML/cycle is achieved at the growth temperature of 400°C with 10 sec of trimethylgallium exposure. At higher growth temperatures, the growth rate does not saturate but increases slowly with increasing exposure. The large physical size and finite decomposition time of the initial adsorbate are suggested as the cause for the dependence of ALE growth rate on alkyl exposure time.
New Group III Precursors for the Movpe of GaAs and InP Based Material
Authors: Hostalhe M. , Pohl L. , Merck E. , Brauers A. , Balk P. , Frese V. , Hardtdegen H. , Hovel R. , Regel G.K. , Molassioti A. , Moser M. , Scholz F. , Schumann H. , Hartmann K.U. , Wassermann W. 
Published: March 2011

AbstractThis paper presents proposals for the synthesis of several group III metal organics (In, Ga, Al compounds) and preliminary results on their use in the MOVPE (metal organic vapor phase epitaxy) of III-V semiconductors. The common feature of all these precursors is that they are saturated by interor intramolecular coordination. They are even non-pyrophoric and air resistant which is an interesting aspect with respect to safe handling. In addition, the compounds are liquid at room temperature with a low but sufficient vapor pressure for MOVPE without additional heating of the source.
Modulation Doped GaAs with Electron Mobilities Exceeding 107cm2/V sec
Authors: Pfeiffer Loren , West K. W. , Stormer H. L. , Baldwin K. W. 
Published: March 2011

AbstractA modulation doped Al.35Ga.65As/GaAs single interface structure using Si delta doping setback from the two dimensional electron gas (2 DEG) by 700Å, was measured in van der Pauw geometry at 0.35K and showed an electron mobility of 1.17× 107 cm2 /V see at a carrier density of 2.2× 1011electrons/cm2. An Al.30Ga.70As/GaAs single quantum-well 250Å wide of similar structure with a 500Å setback yielded a 2 DEG mobility of 5.1× 106 cm2 /Vsec at 3.0×1011 electrons/cm2under similar measurement conditions. These mobilities exceed those previously published by more than a factor of two for the single interface structure, and by nearly an order of magnitude for the quantum-well. The samples were grown by solid source MBE in a Varian Gen II modified with He closed-cycle cryogenic vacuum pumping, and in other ways, to achieve a base pressure of 1.5× 10−12 torr, as measured on a extractor-type ionization gauge that is not subject to the usual x-ray limited reading.
Growth and Characterization of GaAs on Si by Mbe
Authors: Li A.Z. , Wang J.X. , Qiu J.H. , Liang B.W. , Zheng Y.L. , Wang S.B. 
Published: March 2011

AbstractHigh quality of Si-doped n-type MBE GaAs grown directly on 4° off (001) towards [0111 Si substrates has been achieved by a multiple step MBE growth procedure. Epilayers have been characterized for the doping range 2x1016 to 3x1018cm-3 with thickness up to lOm by double crystal x-ray rocking curves, Hall mobilities, photoluminescence spectra, dislocation etching pit densities and I-V characteristics of MESFET of GaAs/Si. The results show that the electron mobilities are 2900 to 1430cm2 /Vs while free electron concentration of 3.5x1017 to 2.7x1018cm-3. The FWHM of the DCRC are 175 to 350 arc sec, the EPD are 1x106 to 2x107 cm-2 for most of samples and both of them appear variation with thickness of epilayer. The main peak of PL appears a few meV shift to long wavelength in comparison with GaAs on GaAs. The FWHM of the PL are 21 meV for n-type GaAs/Si in a doping level of 3.5x1017cm-3. MESFET show a acceptable I-V characteristics. All of epilayers with thickness less than 5pm appear good morphology. Some slightly orthogonal cracking was observed in the 5 to 10µm thick films of GaAs/Si.
Narrow Si doping distributions in 6-doped GaAs, Al0.3Ga0.7As and Quantum Wells grown by Gas Source Molecular Beam Epitaxy
Authors: Cunningham J.E. , Chin T.H. , Tell B. , Jan W. , Ditzenberger J. A. , Kuo T. Y. , Fonstad C. 
Published: March 2011

AbstractWe report very small interdiffusion and surface segregation of Si in δ-doped GaAs, A10.3Gao.7As and Quantum Wells grown at 580 C by Gas Source Molecular Beam Epitaxy. Capacitance-Voltage profiles of δ-doped layers are 38 Å wide for growth at 580 C and further, insignificant profile narrowing is observed at 530C and below. Much wider profiles are observed at equivalent substrate temperature for As4 growth. Atomic diffusion of Si in δ-doped Al0.3Ga0.7As is found to have a rate of D0=5× 10−cm2/sec with an activation energy of 1.8 eV.
Comparison of Interface Formation for GaAs-on-Si and ZnSe-on-Si.
Authors: Bringans R. D. , Olmsteadt Marjorie A. 
Published: March 2011

AbstractA comparison is made between the interface formed when GaAs is grown heteroepitaxially on Si(100) substrates with that formed for ZnSe-on-Si(100) growth. Results of core level photoemission spectroscopy show that the Si(100) surface reacts with As atoms to form a stable monolayer, but reacts with Se atoms to form the compound SiSe2. Annealing treatments can also give rise to a submonolayer coverage of Se atoms on Si(100). The SiSe2 compound is also seen at the interface between ZnSe and Si. Island formation appears to occur at the beginning of growth for both GaAs-on-Si and ZnSe-on-Si
Low Pressure Omcvd Growth of GaAs on InP for Fet and Quantum Well Laser Fabrication
Authors: Bhat R. , Lo Y-H. , Caneau C. , Chang-Hasnain C.J. , Skromme B.J. , Hwang D.M. , Zah C.E. , Koza M.A. 
Published: March 2011

AbstractGallium arsenide epitaxial layers with excellent morphology have been grown by organometallic chemical vapor deposition (OMCVD) on (100) and 2-3° off (100) InP substrates by a modified two-step growth commonly used for GaAs on Si. The layers have been characterized by X-ray diffraction, cross-sectional transmission electron microscopy (TEM), low temperature photoluminescence (PL) and Hall measurements. 1 µm gate GaAs metal-semiconductor field effect transistors (MESFETs) with transconductances as high as 220 mS/mm have been fabricated. These MESFETs have been integrated with buried heterostructure and V-groove InGaAsP lasers. The V-groove laser -MESFET OEIC transmitter has been shown to be capable of direct modulation at 5 Gb/sec bit rate. Finally we have also demonstrated GaAs single quantum well lasers with threshold currents as low as 800 A/cm2for 50 µm wide broad area gain guided devices with 1.25 mm long cavities.
Quaternary Phase Equilibria vs. Strain-Energy at the In.53Ga.47As/InP Interface
Authors: Schultz Allan E. , Chang Y. Austin 
Published: March 2011

AbstractExtensive new data and modeling in the In-Ga-As system has allowed the authors to reexamine the phase equilibria between the melt and the epitaxial solid. A detailed thermodynamic model was constructed with the following improvements: (1) The solid-solid interaction parameters were based on InAs-GaAs miscibility gap data, and (2) liquid-bulk solid, as well as liquid-epitaxial solid, tie-lines were used. Comparison of tie- lines from epitaxial systems and bulk systems demonstrated that strain energy is not the dominant factor in equilibrium growth of epitaxial solid films of In1-xGaxAs on any Ill-V binary substrate. Both the “lattice- pulling” effect and the “substrate-orientation” effect were shown to be caused by different quaternary equilibria at the In1-xGaxAs/InP interface, and not by film-substrate strain.
Properties of Mbe Grown Heterostructures of GaAs/InSb and InP/InSb.
Authors: Asom M. T. , Fitzgerald E. A. , Thiel F. A. , People R. , Eaglesham D. , Luther L. , Sputz S. K. , Kimerling L.C. 
Published: March 2011

AbstractWe have employed molecular beam epitaxy in the growth of InSb on GaAs and InP. The transport, optical and structural properties of the films were investigated by in-situ reflection high energy electron diffraction, Hall effect and temperature dependent Hall effect, photoluminescence, transmission electron microscopy and X-ray diffractometry techniques. We report mobilities of up to 32,000 cm2/volt-sec and free electron concentrations of 3x1016/cm3at room temperature. We have discovered a new defect state in InSb with an energy position of Ec -0.05± 0.006eV. Optical and structural measurements reveal that the differences in thermal expansion and lattice mismatch between the substrates and films results in the broadening of the X-ray diffraction peaks and the near gap photoluminescence linewidths. Furthermore, we observe band gap shifts to higher energies of 10meV and 20meV for growth on GaAs and InP, respectively.
Low Interface State Density at Pseudomorphic ZnSe/Epitaxial GaAs Interface
Authors: Qian Q.-D. , Qiu J. , Kobayashi M. , Gunshor R.L. , Kolodziejski L.A. , Melloch M.R. , Cooper J.A. , Gonsalves J.M. , Otsuka N. 
Published: March 2011

AbstractThe electrical properties of pseudomorphic ZnSe/epilayer GaAs heterointerfaces, grown by MBE, have been investigated by capacitance versus voltage (C-V) and current versus voltage (I- V) measurements. Hole accumulation and inversion were observed in ZnSe/p-GaAs interfaces and ZnSe/n-GaAs interfaces, respectively. The C-V characteristics of the Au/ZnSe/p-GaAs capacitors are nearly ideal, exhibiting an interface state density (2.5x1011cm-2) which compares favorably with the densities reported at AlGaAs/GaAs interfaces.
Study of MBE ZnSe Growth Using Rheed Oscillations
Authors: Turco Francoise S. , Tamargo M.C. 
Published: March 2011

AbstractReflection high energy electron diffraction (RHEED) intensity oscillations are often used to investigate in situ the growth of III-V materials by molecular beam epitaxy (MBE). In this work, we have used RHEED oscillations to perform a quantitative study of the growth mechanisms of ZnSe, a II-VI semiconductor.Our experiments illustrate that the RHEED pattern of ZnSe is far less intense than that of III-V materials grown by MBE, and no specular spot is observed over a wide range of growth conditions. We have, however, been able to record up to 25 oscillations allowing a quantitative study of the growth of ZnSe by MBE. Thus we have used RHEED oscillations to make an in situ systematic study of the influence of the three main growth parameters (substrate temperature and Zn or Se impinging fluxes) on the ZnSe growth rate. We observed that the variation of the ZnSe growth rate is due to a non unity sticking coefficient of both Zn and Se species at the interface in the standard growth conditions used. Our observations can be described using a thermodynamic model and enable us to control the desired growth conditions. Our work demonstrates the utility of RHEED oscillations to understand the MBE growth mechanisms of II-VI compounds.
Charge Carrier Recombination in AlGaAs Studied by Time-Resolved Microwave Conductivity Experiments
Authors: Werner A. , Agarwal A. M. , Moustakas T. D. , Kunst M. 
Published: March 2011

AbstractAlxGa1-xAs films, doped with silicon in the 1 x 1018 cm-3 range, have been prepared in the composition range x = 0.20 - 0.46 by molecular beam epitaxy. The influence of defect states on excess carrier trapping and recombination processes is studied by a contactless transient photoconductivity technique in the microwave region. Effective electron life- times in the 1 x 10-5s range for the 20% Al film down to the 1 x 10-7s range for the 46% Al film were found, indicating a larger density of electron traps in more Al rich films. The decay kinetics in AlGaAs is compared with the decay kinetics in GaAs.
Rocking-Curve Peak Shift in Thin Heterojunction Single Layers
Authors: Wie C.R. , Choi Y-W. , Kim H.M. , Chen J.F. , Vreeland T. , Tsai C.-J. 
Published: March 2011

AbstractA simple method for determining layer composition and mismatch of semiconductor hetero-epitaxial samples is by measuring the separation of peaks in x-ray rocking curve (XRC). This method fails if the peak separation is affected by other factors. For a small layer thickness, the layer peak position is affected by the x-ray amplitudes of the substrate or other thicker layers through the interference and overlap effects. In this case, a diffraction theory fitting process is necessary for a correct determination of layer parameters. We have used dynamical and kinematical x-ray diffraction theories to calculate the layer peak position as a function of its thickness for various layer/substrate combinations. These two theories yield substantially different results, indicating that the kinematical diffraction theory analysis is no longer valid for these thin layers. When a thick layer is present along with the thin layer, the thick layer is more influential than the substrate to the thin layer peak position, making the dynamical theory fitting necessary even from higher thickness.
Formation of Radiative Binding States for the Pairs Between Acceptors in Heavily Acceptor-Doped Gaas.
Authors: Ohnishi Nobukazu , Makita Nunosuke , Shibata Hajime , Beye Aboubaker.C. , Yamada Akimasa , Mori Masahiko 
Published: March 2011

AbstractWe carried out the photoluminescence measurements at low temperature for Be-doped GaAs. Samples were grown by molecular beam epitaxy and Be con- centration was varied by controlling the cell temperature of Be. Besides the well-defined emission, [g-g], which is observed for the acceptor con- centration [A] from ∼ 5x1016 cm-3 to ∼ 1x1018 cm-3 and which shows steep red shift with increasing [A], we observed two unusual emissions temporarily denoted by [g-g]α and [g-g]β. These emissions were commonly observed just below bound exciton emissions for heavily-doped region of [A]>1x1018 cm-3. [g-g]α indicated a strong blue shift with increasing [A] and its energy can become larger than the direct band-gap energy of undoped GaAs at 2K when [A] exceeds 5x1019 cm-3. On the other hand, [g-g]β was observed in the vicinity of the band-to-acceptor emission and showed red shift with increas- ing [A]. We here proposed a model that these two emissions are attributed to the binding states of acceptor-acceptor pair formed by the overlapping of the wave functions in the ground state of an isolated acceptor. This situation is principally different from that of [g-g] in which the formation of acceptor-acceptor pair was ascribed to the overlapping of the wave func- tions of 2P excited state. It was revealed that the theoretical estimation made through the simplified calculation agreed qualitatively well with the dependence of [g-g]β on [A]. However this calculation presented unsatisfac- tory agreement with the features of [g-g]α and it was suggested that another physical conjecture such as a formation of GaAs-Be alloy should be proposed.
Growth of Thin Epitaxial Silicon Layers on Heavily Doped Substrates by RTP-CVD
Authors: Lee S. K. , Ku Y. H. , Kwong D. L. 
Published: March 2011

ABSTRACTSilicon epitaxy plays an important role in improving the performance and reliability of semiconductor devices. The continuous scale-down in device feature size demands a low thermal budget epitaxial technique to maintain the structural integrity of processed devices. In this paper, rapid thermal processing chemical vapor deposition (RTP-CVD) has been used to deposit high quality, thin silicon epitaxial films with superior thickness control. Parameters affecting the quality and rate of epitaxial growth are discussed.
300° C Processing of Si Using Remote Plasma Techniques for In Situ Cleaning, Epitaxy, and Oxide/Nitride/Oxide Depositions
Authors: Fountain G.G. , Hattangady S.V. , Rudder R.A. , Posthill J.B. , Markunas R.J. 
Published: March 2011

ABSTRACTLow temperature Si processing techniques have been developed using remote plasma enhanced chemical vapor techniques. The 300° C in situ processes include indirectly excited hydrogen treatments for obtaining reconstructed Si(100) surfaces, Si/Si(100) homoepitaxy, and deposition of poly-Si/oxide/nitride/oxide/Si(100) structures with no capacitance-voltage hysteresis and low interface state density (4×1010cm−2eV−1). While all these processes have been accomplished with the same tool, the success of the in situ hydrogen treatment and the homoepitaxy are sensitive to the past history of the reactor. In particular, they are sensitive to by-products formed during the oxide deposition process. To eliminate these by-products, plasma conditioning of the chamber walls prior to introduction of the silicon wafer from the load lock has been necessary to obtain reproducible results.
Impact of Patterned Layers on Temperature Non-Uniformity during Rapid Thermal Processing for VLSI-Applications
Authors: Vandenabeele P. , Maex K. , De Keersmaecker R. 
Published: March 2011

ABSTRACTThe influence of patterned oxide layers on temperature non-uniformity during RTP is studied. It is shown that large temperature non-uniformities (up to 80 °C) can occur during RTP as a consequence of large scale patterns of thick oxides. The dependence of oxide thickness and pattern geometry on temperature non-uniformity over a wafer is studied. A set of simulation programs is developed to calculate the optical characteristics of a wafer inside a chamber and to calculate the time dependent temperature non-uniformities on patterned wafers. The calculated results agree very well with the experimental results. The simulation program was used to define the optimal optical conditions for RTP systems for minimal temperature non-uniformity due to patterned overlayers on Si.
Implications of Rapid Thermal Processing for Step Coverage in Low Pressure Chemical Vapor Deposition
Authors: Shemansky Frank A. , Jain Manoj K. , Cale Timothy S. , Raupp Gregory B. 
Published: March 2011

ABSTRACTA multicomponent mathematical model incorporating simultaneous Knudsen diffusion and heterogeneous reaction in a feature of arbitrary geometry has been developed to quantitatively predict step coverage in LPCVD. The single component model reveals that for a given CVD chemistry and feature geometry, deposition uniformity is controlled by a single parameter called the step coverage modulus. In multicomponent systems, each additional reactant partial pressure dependence in the deposition rate expression introduces an additional parameter equal to the ratio of the initial reactant partial pressures. Manipulation of the instantaneous step coverage modulus, through time variations of temperature and/or pressure results in higher average film growth rates without incurring a penalty in step coverage over patterned regions of the wafer. For deposition of SiO2 from TEOS, the step coverage modulus is varied through a time dependent temperature path. The path is chosen by constraining the deposition rate in the feature such that it varies by less than a few percent from top to bottom. For deposition of SiO2 from SiH4/O2, silane partial pressure is varied since the reaction rate is relatively insensitive to temperature. In each case. time savings of approximately 50% are achieved.
Rapid Thermal Annealing of Double Polysilicon Bipolar Transistors
Authors: Patton Evan E. , Yamaguchi Tadanori , Lee June , Tang Alex , Yu Y.-C. S. 
Published: March 2011

ABSTRACTThis paper reports on very shallow double rapid thermally diffused npn transistor junctions, emitter polysilicon sheet resistance, and titanium disilicide formation. A transistor with a 675Å base width fabricated using rapid thermal annealing is demonstrated.
Influence of Rapid Thermal Processing on Minority Carrier Diffusion Length in Silicon
Authors: Eichammer Wolfgang A. , Vu Thuong-QUat , Siffert P. 
Published: March 2011

ABSTRACTMinority carrier diffusion length measurements (SPV-method) are presented which illustrate the role of contamination, residual impurity content and surfaces in the formation of RTP-induced recombination centers.