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Control Of Impurities In The Epitaxial Growth Of High Quality Gaas Response Of The Molecular Beam Mass Spectrometer Analysis And Calibration
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Book Synopsis Control of Impurities in the Epitaxial Growth of High Quality GaAs. Response of the Molecular Beam-Mass Spectrometer Analysis and Calibration by : David A. Stevenson
Download or read book Control of Impurities in the Epitaxial Growth of High Quality GaAs. Response of the Molecular Beam-Mass Spectrometer Analysis and Calibration written by David A. Stevenson and published by . This book was released on 1977 with total page 43 pages. Available in PDF, EPUB and Kindle. Book excerpt: A molecular beam-mass spectrometer (MBMS) has been developed to sample ambient gas atmosphere in epitaxial growth systems at high temperatures and at atmospheric pressure. At present the MBMS is capable of analyzing ppm quantities of gaseous species that result from chemical transport reactions between the ambient H2 atmosphere and the growth system components (e.g., fused quartz and graphite). The MBMS consists of three differentially pumped stages separated by a nozzle and a skimmer orifice and a detector aperture. The gas is expanded through the nozzle to establish a supersonic flow region (Mach disc) which is sampled by the skimmer to develop a well-collimated molecular beam. The molecular beam is then ionized and detected by a quadrapole mass analyser. The response and interpretation of the data from the MBMS are analyzed and discussed to obtain an overall calibration of the system. The sensitivity for most gaseous species in H2 at atmospheric pressure and at 800 C is better than 1 ppm without chopping the beam. Initial results indicate that there are ppm levels of Ar, CO and H2O in palladium purified H2. In addition, the formation of SiO and H2O by chemical transport reactions between H2 and fused quartz at 700 C and above are in good agreement with existing high temperature thermodynamic data. (Author).
Book Synopsis Control of Impurities in the Epitaxial Growth of High Quality GaAs by : David A. Stevenson
Download or read book Control of Impurities in the Epitaxial Growth of High Quality GaAs written by David A. Stevenson and published by . This book was released on 1983 with total page 17 pages. Available in PDF, EPUB and Kindle. Book excerpt: A research program is described on the topic of impurity incorporation during the growth of GaAs epitaxial layers. The major portion of the research was the design, construction, and characterization of a molecular beam mass spectrometry (MBMS) system and its use as a diagnostic analytical tool to evaluate typical gaseous environments used in the growth of III-V single crystal layers. The fundamental gas dynamics of the MBMS sampling process were studied as well as the limitations and correction factors for this technique. Two crystal growth environments were analyzed: a liquid phase epitaxial (LPE) GaAs growth system; and an organometallic vapor phase epitaxy (OMVPE) system. In the former system, it was shown that there are significant concentrations of O, C, Si gaseous species in the gas ambient which appear to be the major potential impurities. For OMVPE, two topics were emphasized: the side reactions of the organometallic (OM) reactants, particularly those involving oxygen containing species; and the graphite-OM interaction.
Book Synopsis Scientific and Technical Aerospace Reports by :
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1988 with total page 964 pages. Available in PDF, EPUB and Kindle. Book excerpt: Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.
Book Synopsis Government Reports Announcements & Index by :
Download or read book Government Reports Announcements & Index written by and published by . This book was released on 1992 with total page 1336 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Ultra-High-Quality GaAs and AlAs Two-Dimensional Electron Systems Via Molecular Beam Epitaxy by : Yoon Jang Chung
Download or read book Ultra-High-Quality GaAs and AlAs Two-Dimensional Electron Systems Via Molecular Beam Epitaxy written by Yoon Jang Chung and published by . This book was released on 2021 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work summarizes how to prepare high-quality GaAs and AlAs two-dimensional electron systems (2DESs) via molecular beam epitaxy (MBE). At the time of writing this thesis samples grown using the methods provided here hold world-record results for mobility in both GaAs and AlAs 2DESs. This was achieved by optimization of sample design and systematic reduction of impurities in the structure. In the first few chapters, the working principles of electron transfer in the process of forming a 2DES in AlAs and GaAs quantum wells (QWs) is established. We show that AlAs 2DESs can be prepared in a fashion analogous to that of modulation-doped GaAs 2DESs. Moreover, we elaborate on how the more sophisticated doping-well structure, commonly used for ultra-high-mobility samples, works. Several experimental parameters are tuned in the doped region and their impact on the resultant 2DES density is discussed. Finally, we also demonstrate a heterostructure design that allows the preparation of high-quality, high-density GaAs 2DESs at elevated hydrostatic pressures. The new scheme suppresses the reduction of electron density as a function of pressure by more than a factor of 3. The latter chapters discuss impurities incorporated during the MBE growth of GaAs and AlAs. We start off by devising a strategy to evaluate the cleanliness of our source material. Because the sensitivity of conventional analysis tools such as secondary ion mass spectrometry is too low to probe the amount of impurities in ultra-high-quality GaAs samples, we use the mobility of a specially designed GaAs 2DES as a metric for cleanliness. The main idea here is to exploit the surface segregation of impurities on the growth front, explained in finer detail in the main text. With the cleanliness being quantifiable, we systematically purified our source material until no significant improvement could be observed by offline bakes. This soft limit on sample cleanliness can be lifted by improving the vacuum in our MBE chamber, which we achieve by implementing additional cryogenic cold plates in the growth space. Under the best conditions of source purity and vacuum, we were able to grow samples that demonstrate the highest electron mobilities in the world.
Download or read book Solid State Technology written by and published by . This book was released on 1978 with total page 1268 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis The Molecular Beam Epitaxial Growth of High Quality GaAs-A1GaAs Heterostructures for Microwave Device Applications by : Paul A. Maki
Download or read book The Molecular Beam Epitaxial Growth of High Quality GaAs-A1GaAs Heterostructures for Microwave Device Applications written by Paul A. Maki and published by . This book was released on 1986 with total page 626 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Government reports annual index by :
Download or read book Government reports annual index written by and published by . This book was released on 1978 with total page 1268 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis The molecular beam epitaxial growth of high quality GaAs-AlGaAs heterostructures for microwave device applications by : Paul A. Maki
Download or read book The molecular beam epitaxial growth of high quality GaAs-AlGaAs heterostructures for microwave device applications written by Paul A. Maki and published by . This book was released on 1986 with total page 281 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Characterization of Impurities and Degradants Using Mass Spectrometry by : Guodong Chen
Download or read book Characterization of Impurities and Degradants Using Mass Spectrometry written by Guodong Chen and published by John Wiley & Sons. This book was released on 2011-04-27 with total page 402 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book highlights the current practices and future trends in structural characterization of impurities and degradants. It begins with an overview of mass spectrometry techniques as related to the analysis of impurities and degradants, followed by studies involving characterization of process related impurities (including potential genotoxic impurities), and excipient related impurities in formulated products. Both general practitioners in pharmaceutical research and specialists in analytical chemistry field will benefit from this book that will detail step-by-step approaches and new strategies to solve challenging problems related to pharmaceutical research.
Book Synopsis Kinetic Aspects of Lattice Mismatch in Molecular Beam Epitaxial Growth on Planar and Patterned Substrates by :
Download or read book Kinetic Aspects of Lattice Mismatch in Molecular Beam Epitaxial Growth on Planar and Patterned Substrates written by and published by . This book was released on 1993 with total page 69 pages. Available in PDF, EPUB and Kindle. Book excerpt: This final scientific report summarizes the salient accomplishments under the grant AFOSR 90-0184 which include (i) the first demonstration of the realization of 3-dimensionally confined (i.e. quantum box) GaAs structures via a one-step MBE growth on pre-patterned nonplanar GaAs(111)B and GaAs(100) substrates and exhibiting optical activity, (ii) the first demonstration of the kinetics of highly strained InGaAs 3D island and defect formation and the potential use of such coherent islands as quantum boxes, (iii) introduction of the idea of substrate encoded size-reducing epitaxy (SESRE) that underlies (i) above and provides a means for exploiting (ii) for the creation of a regular array of coherent 3D InAs islands as a quantum box array, (iv) realization of high quality, highly strained GaAs/InGaAs/AlGaAs single and multiple quantum well structures via RHEED optimized growth kinetics control and their application to high performance resonant tunnelling diodes, doped-channel MISFETs, and asymmetric Fabry-Perot spatial light modulators in a novel inverted cavity geometry, (v) the impact of ex-situ processing steps such as dielectric encapsulation and rapid thermal annealing, and (vi) the use of Ga+ focused ion beam for in-situ direct-write patterning of GaAs.
Book Synopsis Morphological Imperfections Associated with Molecular Beam Epitaxial Growth of GaAs Layers by : N. J. Kadhim
Download or read book Morphological Imperfections Associated with Molecular Beam Epitaxial Growth of GaAs Layers written by N. J. Kadhim and published by . This book was released on 1987 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Laser-assisted Molecular Beam Epitaxial Growth of GaAs on Si (100) by : F. J. Grunthaner
Download or read book Laser-assisted Molecular Beam Epitaxial Growth of GaAs on Si (100) written by F. J. Grunthaner and published by . This book was released on 1988 with total page 18 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Molecular Beam Epitaxial Growth and Material Properties of GaAs and AlGaAs on Si(100). by : W. I. Wang
Download or read book Molecular Beam Epitaxial Growth and Material Properties of GaAs and AlGaAs on Si(100). written by W. I. Wang and published by . This book was released on 1984 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis A Feasibility Study of Ion Implantation Techniques for Mass Spectrometer Calibration by :
Download or read book A Feasibility Study of Ion Implantation Techniques for Mass Spectrometer Calibration written by and published by . This book was released on 1978 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt: An experimental study was undertaken to examine the feasibility of using ion-implanted filaments doped with either an alkali metal or noble gas for in situ recalibration of onboard mass spectrometers during extended space missions. Implants of rubidium and krypton in rhenium ribbon filaments were subsequently tested in a bakeable 60 deg sector mass spectrometer operating in the static mode. Surface ionization and electron impact ion sources were both used, each yielding satisfactory results. The metallic implant with subsequent ionization provided a means of mass scale calibration and determination of system operating parameters, whereas the noble gas thermally desorbed into the system was more suited for partial pressure and sensitivity determinations.
Book Synopsis Molecular Beam Epitaxial Growth of GaAs/AlGaAs Heterostructure and Nitrogen-containing Alloy on Patterned Substrate by : Wan Khai Loke
Download or read book Molecular Beam Epitaxial Growth of GaAs/AlGaAs Heterostructure and Nitrogen-containing Alloy on Patterned Substrate written by Wan Khai Loke and published by . This book was released on 2003 with total page 108 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Molecular Beam Epitaxial Growth and Characterization of GaAs/AlGaAs Thin Films and Multilayer Structures by : Yuh-Haw Wu
Download or read book Molecular Beam Epitaxial Growth and Characterization of GaAs/AlGaAs Thin Films and Multilayer Structures written by Yuh-Haw Wu and published by . This book was released on 1984 with total page 314 pages. Available in PDF, EPUB and Kindle. Book excerpt:
