Use of the photoluminescence intensity variation as an in-situ probe for electrochemical copper deposition on a p-type GaAs electrode

1998 ◽  
Vol 1 (11) ◽  
pp. 719-724 ◽  
Author(s):  
Éliane Sutter ◽  
Jacky Vigneron ◽  
Isabelle Gérard ◽  
Arnaud Etcheberry
Keyword(s):  
Intensity Variation ◽  
Copper Deposition ◽  
Photoluminescence Intensity ◽  
P Type

Atomic Layer Controlled Substitutional Doping With Lithium in ZnSe

1991 ◽  
Vol 222 ◽  
Author(s):  
Ziqiang Zhu ◽  
Mitsuo Kawashima ◽  
Takafumi Yao
Keyword(s):  
Adsorption Process ◽  
Intensity Variation ◽  
Atomic Layer ◽  
High Energy ◽  
Substitutional Doping ◽  
Dynamical Behaviors ◽  
Adsorption Processes ◽  
Li Adsorption ◽  
P Type

ABSTRACTThe detailed observation of dynamical behaviors of reflection high energy electron diffraction (RHEED) patterns during the adsorption processes of Li, Se and Zn is carried out. It is found that the RHEED intensity variation reflects the Li surface coverage during Li adsorption process on a Secovered surface. This fact enables one to control quantitatively the doping of Li “in situ”. A new method for atomic-layer controlled substitutional doping of ZnSe layers with lithium is proposed based on the RHEED investigations. The method allows the incorporation of Li dopants on Zn-sites of ZnSe by monitoring the RHEED patterns and intensities, and is expected to suppress the compensation by Li interstitials. Photoluminescence spectrum shows the growth of high quality p-type layers.

Convergent-beam thickness determination: The advantages of digital imaging

1994 ◽  
Vol 52 ◽  
pp. 420-421
Author(s):  
Stuart McKernan ◽  
C. Barry Carter
Keyword(s):  
Intensity Variation ◽  
Convergent Beam Electron Diffraction ◽  
Digital Data ◽  
Thickness Determination ◽  
Frequent Use ◽  
Automated Processing ◽  
Beam Thickness ◽  
Convergent Beam ◽  
Remarkable Agreement

Convergent-beam electron diffraction (CBED) patterns contain an immense amount of information relating to the structure of the material from which they are obtained. The analysis of these patterns has progressed to the point that under appropriate, well specified conditions, the intensity variation within the CBED discs may be understood in a quantitative sense. Rossouw et al for example, have produced numerical simulations of zone-axis CBED patterns which show remarkable agreement with experimental patterns. Spence and co-workers have obtained the structure factor parameters for lowindex reflections using the intensity variation in 2-beam CBED patterns. Both of these examples involve the use of digital data. Perhaps the most frequent use for quantitative CBED analysis is the thickness determination described by Kelly et al. This analysis has been implemented in a variety of different ways; from real-time, in-situ analysis using the microscope controls, to measurements of photographic prints with a ruler, to automated processing of digitally acquired images. The potential advantages of this latter process will be presented.

Low-Temperature LPCVD MEMS Technologies

2002 ◽  
Vol 729 ◽  
Author(s):  
Roger T. Howe ◽  
Tsu-Jae King
Keyword(s):  
Silicon Germanium ◽  
Polycrystalline Silicon ◽  
Rf Mems ◽  
Sige Layer ◽  
Copper Metallization ◽  
Si Films ◽  
P Type ◽  
Mems Process ◽  
Post Deposition

AbstractThis paper describes recent research on LPCVD processes for the fabrication of high-quality micro-mechanical structures on foundry CMOS wafers. In order to avoid damaging CMOS electronics with either aluminum or copper metallization, the MEMS process temperatures should be limited to a maximum of 450°C. This constraint rules out the conventional polycrystalline silicon (poly-Si) as a candidate structural material for post-CMOS integrated MEMS. Polycrystalline silicon-germanium (poly-SiGe) alloys are attractive for modular integration of MEMS with electronics, because they can be deposited at much lower temperatures than poly-Si films, yet have excellent mechanical properties. In particular, in-situ doped p-type poly-SiGe films deposit rapidly at low temperatures and have adequate conductivity without post-deposition annealing. Poly-Ge can be etched very selectively to Si, SiGe, SiO2 and Si3N4 in a heated hydrogen peroxide solution, and can therefore be used as a sacrificial material to eliminate the need to protect the CMOS electronics during the MEMS-release etch. Low-resistance contact between a structural poly-SiGe layer and an underlying CMOS metal interconnect can be accomplished by deposition of the SiGe onto a typical barrier metal exposed in contact windows. We conclude with directions for further research to develop poly-SiGe technology for integrated inertial, optical, and RF MEMS applications.

scholarly journals Porous Silicon Structural Evolution from In-Situ Luminescence and Raman Measurements

1996 ◽  
Vol 431 ◽  
Author(s):  
D. R. Tallant ◽  
M. J. Kelly ◽  
T. R. Guilinger ◽  
R. L. Simpson
Keyword(s):  
Porous Silicon ◽  
Silicon Surface ◽  
Structural Evolution ◽  
Surface Oxidation ◽  
Ethanol Solution ◽  
Nonradiative Recombination ◽  
Photoluminescence Intensity ◽  
Exciton Migration ◽  
Photoluminescence Mechanism

AbstractWe performed in-situ photoluminescence and Raman measurements on an anodized silicon surface in the HF/ethanol solution used for anodization. The porous silicon thereby produced, while resident in HF/ethanol, does not immediately exhibit intense photoluminescence. Intense photoluminescence develops spontaneously in HF/ethanol after 18–24 hours or with replacement of the HF/ethanol with water. These results support a quantum confinement mechanism in which exciton migration to traps and nonradiative recombination dominates the de-excitation pathways until silicon nanocrystals are physically separated and energetically decoupled by hydrofluoric acid etching or surface oxidation. The porous silicon surface, as produced by anodization, shows large differences in photoluminescence intensity and peak wavelength over millimeter distances. Parallel Raman measurements implicate nanometer-size silicon particles in the photoluminescence mechanism.

scholarly journals The evolution of the metazoan Toll receptor family and its expression during protostome development

2021 ◽  
Author(s):  
Andrea Orús-Alcalde ◽  
Tsai-Ming Lu ◽  
Andreas Hejnol
Keyword(s):  
Phylogenetic Analysis ◽  
Transmembrane Domain ◽  
Leucine Rich Repeat ◽  
Animal Development ◽  
Phylogenetic Studies ◽  
Repeat Domain ◽  
Toll Receptor ◽  
P Type

Abstract Background: Toll-like receptors (TLRs) play a crucial role in immunity and development. They contain leucine-rich repeat domains, one transmembrane domain, and one Toll/IL-1 receptor domain. TLRs have been classified into V-type/scc and P-type/mcc TLRs, based on differences in the leucine-rich repeat domain region. Although TLRs are widespread in animals, detailed phylogenetic studies of this gene family are lacking. Here we aim to uncover TLR evolution by conducting a survey and a phylogenetic analysis in species across Bilateria. To discriminate between their role in development and immunity we furthermore analyzed stage-specific transcriptomes of the ecdysozoans Priapulus caudatus and Hypsibius exemplaris, and the spiralians Crassostrea gigas and Terebratalia transversa.Results: We detected a low number of TLRs in ecdysozoan species, and multiple independent radiations within the Spiralia. V-type/scc and P-type/mcc type-receptors are present in cnidarians, protostomes and deuterostomes, and therefore they emerged early in TLR evolution, followed by a loss in xenacoelomorphs. Our phylogenetic analysis shows that TLRs cluster into three major clades: clade α is present in cnidarians, ecdysozoans, and spiralians; clade β in deuterostomes, ecdysozoans, and spiralians; and clade γ is only found in spiralians. Our stage-specific transcriptome and in situ hybridization analyses show that TLRs are expressed during development in all species analyzed, which indicates a broad role of TLRs during animal development.Conclusions: Our findings suggest that the bilaterian TLRs likely emerged by duplication from a single TLR encoding gene (proto-TLR) present in the last common cnidarian-bilaterian ancestor. This proto-TLR gene duplicated before the split of protostomes and deuterostomes; a second duplication occurred in the lineage to the Trochozoa. While all three clades further radiated in several spiralian lineages, specific TLRs clades have been presumably lost in others. Furthermore, the expression of the majority of these genes during protostome ontogeny suggests their involvement in immunity and development.

In situ Mg surface treatment of p-type GaN grown by ammonia-molecular-beam epitaxy for efficient Ohmic contact formation

2003 ◽  
Vol 82 (5) ◽  
pp. 736-738 ◽  
Author(s):  
H. Tang ◽  
J. A. Bardwell ◽  
J. B. Webb ◽  
S. Rolfe ◽  
Y. Liu ◽  
...  
Keyword(s):  
Molecular Beam Epitaxy ◽  
Surface Treatment ◽  
Ohmic Contact ◽  
Molecular Beam ◽  
Contact Formation ◽  
P Type ◽  
Ohmic Contact Formation

Properties of Nanocrystalline 3C-SiC:H and SiC:Ge:H Films Deposited at Low Substrate Temperatures

2006 ◽  
Vol 910 ◽  
Author(s):  
Shinsuke Miyajima ◽  
Akira Yamada ◽  
Makoto Konagai
Keyword(s):  
Silicon Carbide ◽  
Chemical Vapor ◽  
Hot Wire ◽  
Germanium Alloy ◽  
Temperature Deposition ◽  
P Type ◽  
Cubic Silicon Carbide ◽  
Charged Defects ◽  
Substrate Temperatures

AbstractWe have investigated properties of nanocrystalline hydrogenated cubic silicon carbide (nc-3C-SiC:H) and silicon carbide: germanium alloy (nc-SiC:Ge:H) films deposited by hot-wire chemical vapor deposition (HWCVD) at low temperatures of about 300°C. we found that the density of charged defects was strongly influenced by grain size of the films. In-situ doping into nc-3C-SiC:H films was also carried out. N-type nc-3C-SiC:H films were successfully deposited by using phosphine (PH3) and hexamethyldisilazane (HMDS) as dopants. We found that HMDS is an effective n-type dopant for low temperature deposition of nc-3C-SiC:H films by HWCVD. For the deposition of p-type nc-3C-SiC:H with trimethylaluminum (TMA), it was found that the substrate temperature of above 300°C is required to activate the acceptors. We added dimethylgermane (DMG) into mixture of MMS and H2 to prepare nc-SiC:Ge:H films. The nc-SiC:Ge:H films with Ge mole fraction of 1.9% were successfully deposited.

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