A New Type of Cylindrical a-Si:H X-Ray Detector

1996 ◽  
Vol 420 ◽  
Author(s):  
D. Link ◽  
H. Keppner ◽  
P. Chabloz ◽  
A. Shah ◽  
J.-F. Germond ◽  
...  
Keyword(s):  
Amorphous Silicon ◽  
Deposition Rate ◽  
Successful Development ◽  
Detector Performance ◽  
X Ray ◽  
Deposition Parameters ◽  
New Type ◽  
Powder Formation

AbstractThe present paper describes a new type of cylindrical X-ray detector based on thick amorphous silicon diodes. The authors report on the successful development of these detectors that have diameters as small as 3mm. The effect of silane dilution in hydrogen on deposition rate, powder formation, layer adhesion and detector performance is discussed. A set of deposition parameters is presented, that allows a reasonable compromise between the mentioned effects. First prototypes of this type of dosimeter have been characterised with the radiation from a 60Co source in a hospital. The corresponding results and interpretation are given in this paper.

Single Wafer Amorphous Silicon Process Evaluation

1997 ◽  
Vol 467 ◽  
Author(s):  
David O'Meara ◽  
Chow Ling Chang ◽  
Roc Blumenthal ◽  
Rama I. Hegde ◽  
Lata Prabhu ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Surface Morphology ◽  
Amorphous Silicon ◽  
Deposition Rate ◽  
Cross Sections ◽  
Growth Conditions ◽  
Degree Of Crystallinity ◽  
Deposition Parameters ◽  
Before And After ◽  
Production Requirement

ABSTRACTSingle wafer amorphous silicon deposition was characterized through process modeling and film characterization for application in semiconductor production. DOE methodology was used to determine the main deposition parameters, and the responses were limited to device production requirement properties of surface roughness, deposition rate and degree of crystallinity of the as-deposited film. The data trends and models show that deposition temperature and silane flow are the main factors. Increasing either or both factor increases the deposition rate and the surface roughness. The surface morphology, evaluated by AFM, SEM and TEM, was found to be rougher at extreme growth conditions than the poly crystalline film formed after anneal. The as-deposited surface morphology was not a result of pre-anneal crystal formations as determined by TEM cross sections of samples before and after anneal. Lack of crystalinity is important for impurity diffusion considerations. Device application of the single wafer a-Si process will be a compromise between growth rate (and associated throughput) and surface roughness that can be tolerated.

Hydrogenated Amorphous Silicon Grown by Hot-Wire CVD at Deposition Rates up to 1 µm/minute

2000 ◽  
Vol 609 ◽  
Author(s):  
Brent P. Nelson ◽  
Yueqin Xu ◽  
A. Harv Mahan ◽  
D.L. Williamson ◽  
R.S. Crandal
Keyword(s):  
Amorphous Silicon ◽  
Deposition Rate ◽  
Defect Density ◽  
Hydrogenated Amorphous Silicon ◽  
Conductivity Ratio ◽  
Hot Wire ◽  
Single Filament ◽  
Deposition Rates ◽  
X Ray ◽  
Hydrogenated Amorphous

ABSTRACTWe grow hydrogenated amorphous-silicon (a-Si:H) by the hot-wire chemical vapor deposition (HWCVD) technique. In our standard tube-reactor we use a single filament, centered 5 cm below the substrate and obtain deposition rates up to 20 Å/s. However, by adding a second filament, and decreasing the filament-to-substrate distance, we are able to grow a-Si:H at deposition rates exceeding 167 Å/s (1 µm/min). We find the deposition rate increases with increasing deposition pressure, silane flow rate, and filament current and decreasing filament-tosubstrate distance. There are significant interactions among these parameters that require optimization to grow films of optimal quality for a desired deposition rate. Using our best conditions, we are able to maintain an AM1.5 photoconductivity-to-dark-conductivity ratio of 105 at deposition rates up to 130 Å/s, beyond which the conductivity ratio decreases. Other electronic properties decrease more rapidly with increasing deposition rate, including the ambipolar diffusion length, Urbach energy, and the as-grown defect density. Measurements of void density by small-angle X-ray scattering (SAXS) reveal an increase by well over an order of magnitude when going from one to two filaments. However, both Raman and X-ray diffraction (XRD) measurements show no change in film structure with increasing deposition rates up to 144 Å/s, and atomic force microscopy (AFM) reveals little change in topology.

scholarly journals E-Beam Deposition of Scandia-Stabilized Zirconia (ScSZ) Thin Films Co-Doped with Al

Coatings ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 870
Author(s):  
Nursultan Kainbayev ◽  
Mantas Sriubas ◽  
Kristina Bockute ◽  
Darius Virbukas ◽  
Giedrius Laukaitis
Keyword(s):  
Thin Films ◽  
Chemical Composition ◽  
Deposition Rate ◽  
Photoelectron Spectroscopy ◽  
Cubic Phase ◽  
X Ray Diffraction ◽  
Stabilized Zirconia ◽  
X Ray ◽  
Deposition Parameters ◽  
High Concentrations

Scandia alumina stabilized zirconia (ScAlSZ) thin films were deposited using e-beam evaporation, and the effects of deposition parameters on the structure and chemical composition were investigated. The analysis of thin films was carried out using Energy-dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), X-Ray Diffraction Analysis (XRD) and Raman spectroscopy methods. It was found that the chemical composition of ScAlSZ thin films was different from the chemical composition of the initial powder. Moreover, the Al concentration in thin films depends on the deposition rate, resulting in a lower concentration using a higher deposition rate. XPS analysis revealed that ZrOx, oxygen vacancies, high concentrations of Al2O3 and metallic Al exist in thin films and influence their structural properties. The crystallinity is higher when the concentration of Al is lower (higher deposition rate) and at higher substrate temperatures. Further, the amount of cubic phase is higher and the amount of tetragonal phase lower when using a higher deposition rate.

Deposition Conditions for Large Area PECVD of Amorphous Silicon

1997 ◽  
Vol 467 ◽  
Author(s):  
J. Kuske ◽  
U. Stephan ◽  
W. Nowak ◽  
S. Röhlecke ◽  
A. Kottwitz
Keyword(s):  
Film Thickness ◽  
Amorphous Silicon ◽  
Deposition Rate ◽  
Excitation Frequency ◽  
Input Power ◽  
High Deposition Rate ◽  
Large Area ◽  
Deposition Parameters ◽  
Plate Size ◽  
Area Deposition

ABSTRACTThe production of amorphous silicon devices usually requires large area, high-deposition-rate plasma reactors. Non-uniformity of the film thickness at high power and deposition rate is found to be an important factor for large area deposition.Increasing the radio frequency from the conventional 13.56 MHz up to VHF has demonstrated advantages for the deposition of a-Si:H films, including higher deposition rates and lower particle generation. The use of VHF for large area deposition leads to the generation of standing waves and evanescent waveguide modes at the electrode surface and on the power feeding lines. Thereby increasing the non-uniformity of the film thickness. The uniformity of the film thickness for an excitation frequency strongly depends on the deposition parameters e.g. pressure, input power, silane flow and the value of load impedances. With increasing exciting frequencies the range of deposition parameters for obtaining uniform films narrows.Subsequently it is shown that for a large-area plasma-box reactor (500 × 600 mm2 plate size) with a double-sided RF electrode, the non-uniformity of the film decreases due to a homoge-neization of the electrode voltage distribution by using multiple power supplies and load impedances on the end of the RF electrode. The uniformity errors decrease from ±20% to ±2.4% (27.12MHz) and from ±40% to ±5.9% (54.24MHz). Experimental results of the film uniformity will be discussed in dependence on excitation frequencies and the deposition parameters.

(111) Monocrystalline Nickel Films

1972 ◽  
Vol 30 ◽  
pp. 512-513
Author(s):  
T.E. Pratt ◽  
R.W. Vook
Keyword(s):  
Film Thickness ◽  
Deposition Rate ◽  
Room Temperature ◽  
Narrow Range ◽  
High Vacuum ◽  
Residual Pressure ◽  
Temperature Dependent ◽  
Deposition Parameters ◽  
Transmission Electron ◽  
Substrate Temperatures

(111) oriented thin monocrystalline Ni films have been prepared by vacuum evaporation and examined by transmission electron microscopy and electron diffraction. In high vacuum, at room temperature, a layer of NaCl was first evaporated onto a freshly air-cleaved muscovite substrate clamped to a copper block with attached heater and thermocouple. Then, at various substrate temperatures, with other parameters held within a narrow range, Ni was evaporated from a tungsten filament. It had been shown previously that similar procedures would yield monocrystalline films of CU, Ag, and Au.For the films examined with respect to temperature dependent effects, typical deposition parameters were: Ni film thickness, 500-800 A; Ni deposition rate, 10 A/sec.; residual pressure, 10-6 torr; NaCl film thickness, 250 A; and NaCl deposition rate, 10 A/sec. Some additional evaporations involved higher deposition rates and lower film thicknesses.Monocrystalline films were obtained with substrate temperatures above 500° C. Below 450° C, the films were polycrystalline with a strong (111) preferred orientation.

High-purity Ge x-ray detectors: Sensitivity factors and usefulness

1990 ◽  
Vol 48 (2) ◽  
pp. 548-548
Author(s):  
E. B. Steel
Keyword(s):  
High Purity ◽  
High Energy ◽  
Quantitative Chemical Analysis ◽  
Detector Performance ◽  
X Ray ◽  
Detector Sensitivity ◽  
Specimen Holder ◽  
Many Instruments ◽  
Charge Resolution ◽  
Sensitivity Factors

High Purity Germanium (HPGe) x-ray detectors are now commercially available for the analytical electron microscope (AEM). The detectors have superior efficiency at high x-ray energies and superior resolution compared to traditional lithium-drifted silicon [Si(Li)] detectors. However, just as for the Si(Li), the use of the HPGe detectors requires the determination of sensitivity factors for the quantitative chemical analysis of specimens in the AEM. Detector performance, including incomplete charge, resolution, and durability has been compared to a first generation detector. Sensitivity factors for many elements with atomic numbers 10 through 92 have been determined at 100, 200, and 300 keV. This data is compared to Si(Li) detector sensitivity factors.The overall sensitivity and utility of high energy K-lines are reviewed and discussed. Many instruments have one or more high energy K-line backgrounds that will affect specific analytes. One detector-instrument-specimen holder combination had a consistent Pb K-line background while another had a W K-line background.

Crystal structure of an inclusion complex between chiral monoaza-15-crown-5 and S(–)-1-phenyl-ethyl ammonium percholorate

2003 ◽  
Vol 218 (5) ◽  
Author(s):  
Süheyla Özbey ◽  
F. B. Kaynak ◽  
M. Toğrul ◽  
N. Demirel ◽  
H. Hoşgören
Keyword(s):  
Crystal Structure ◽  
Inclusion Complex ◽  
Single Crystal ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray ◽  
New Type

AbstractA new type of inclusion complex, S(–)-1 phenyl ethyl ammonium percholorate complex of R-(–)-2-ethyl - N - benzyl - 4, 7, 10, 13 - tetraoxa -1- azacyclopentadecane, has been prepared and studied by NMR, IR and single crystal X-ray diffraction techniques. The compound crystallizes in space group

A 2-D Zn(II) coordination polymer based on 4,5-imidazoledicarboxylate and bis(benzimidazole) ligands: synthesis, crystal structure and fluorescence properties

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Xinzhao Xia ◽  
Lixian Xia ◽  
Geng Zhang ◽  
Yuxuan Jiang ◽  
Fugang Sun ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Coordination Polymer ◽  
Zigzag Chain ◽  
Supramolecular Framework ◽  
X Ray Diffraction ◽  
Hydrothermal Conditions ◽  
Hydrogen Bond Interaction ◽  
X Ray ◽  
New Type ◽  
Solid State Fluorescence

Abstract In this work, a new type of zinc(II) coordination polymer {[Zn(HIDC)(BBM)0.5]·H2O} n (Zn-CP) was synthesized using 4,5-imidazoledicarboxylic acid (H3IDC) and 2,2-(1,4-butanediyl)bis-1,3-benzimidazole (BBM) under hydrothermal conditions. Its structure has been characterized by infrared spectroscopy, elemental analysis and single crystal X-ray diffraction analysis. The Zn(II) ion is linked by the HIDC2− ligand to form a zigzag chain by chelating and bridging, and then linked by BBM to form a layered network structure. Adjacent layers are further connected by hydrogen bond interaction to form a 3-D supramolecular framework. The solid-state fluorescence performance of Zn-CP shows that compared with free H3IDC ligand, its fluorescence intensity is significantly enhanced.

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