Self-Diffusion in Covalent Amorphous Solids – A Comparative Study Using Neutron Reflectometry and SIMS

2007 ◽  
Vol 263 ◽  
pp. 51-56 ◽  
Author(s):  
Harald Schmidt ◽  
Mukul Gupta ◽  
Udo Geckle ◽  
Michael Bruns
Keyword(s):  
Secondary Ion Mass Spectrometry ◽  
Diffusion Length ◽  
Diffusion Processes ◽  
Amorphous Solid ◽  
Amorphous Solids ◽  
Neutron Reflectometry ◽  
Amorphous Silicon Nitride ◽  
Self Diffusion ◽  
Secondary Ion

The self-diffusion of nitrogen is studied in amorphous silicon nitride, which is a model system for a covalently bound amorphous solid with a low atomic mobility where reliable diffusion data are still lacking. Comparative experiments on Si14Nx/Si15Nx (x ≈ 1.33) isotope multilayers were carried out with secondary ion mass spectrometry (SIMS) and neutron reflectometry (NR), respectively. It was found that experiments with SIMS are not very well suited for the determination of diffusivities in a broad temperature range. The minimum diffusion length of about 5-10 nm detectable with this method is too large. At high temperatures (> 1200 °C) the amorphous solid crystallizes before any diffusion is measured and at low temperatures (< 1100 °C) the diffusivities are too low to be detected. In contrast, with neutron reflectometry diffusion lengths in the order of 1 nm and diffusivities down to 10-24 m2 s-1 were measured between 950 and 1250 °C. The potential of this method for the determination of ultra slow diffusion processes is discussed.

scholarly journals Transport and Electromechanical Properties of Ca3TaGa3Si2O14 Piezoelectric Crystals at Extreme Temperatures

MRS Advances ◽  
2019 ◽  
Vol 4 (09) ◽  
pp. 515-521
Author(s):  
Yuriy Suhak ◽  
Ward L. Johnson ◽  
Andrei Sotnikov ◽  
Hagen Schmidt ◽  
Holger Fritze
Keyword(s):  
Secondary Ion Mass Spectrometry ◽  
Tone Burst ◽  
Total Conductivity ◽  
Transport Mechanisms ◽  
Electromechanical Properties ◽  
Self Diffusion ◽  
Oxygen Ion ◽  
Piezoelectric Strain ◽  
Secondary Ion ◽  
Diffusion Profiles

ABSTRACTTransport mechanisms in structurally ordered piezoelectric Ca3TaGa3Si2O14 (CTGS) single crystals are studied in the temperature range of 1000-1300 °C by application of the isotope 18O as a tracer and subsequent analysis of diffusion profiles of this isotope using secondary ion mass spectrometry (SIMS). Determined oxygen self-diffusion coefficients enable calculation of oxygen ion contribution to the total conductivity, which is shown to be small. Since very low contributions of the cations have to be expected, the total conductivity must be dominated by electron transport. Ion and electron conductivities are governed by different mechanisms with activation energies (1.9±0.1) eV and (1.2±0.07) eV, respectively. Further, the electromechanical losses are studied as a function of temperature by means of impedance spectroscopy on samples with electrodes and a contactless tone-burst excitation technique. At temperatures above 650 °C the conductivity-related losses are dominant. Finally, the operation of CTGS resonators is demonstrated at cryogenic temperatures and materials piezoelectric strain constants are determined from 4.2 K to room temperature.

scholarly journals Self- and Dopant Diffusion in Extrinsic Boron Doped Isotopically Controlled Silicon Multilayer Structures

2002 ◽  
Vol 719 ◽  
Author(s):  
Ian D. Sharp ◽  
Hartmut A. Bracht ◽  
Hughes H. Silvestri ◽  
Samuel P. Nicols ◽  
Jeffrey W. Beeman ◽  
...  
Keyword(s):  
Multilayer Structure ◽  
Secondary Ion Mass Spectrometry ◽  
Diffusion Processes ◽  
Quantitative Description ◽  
Multilayer Structures ◽  
Dopant Diffusion ◽  
Enhanced Diffusion ◽  
Self Diffusion ◽  
Boron Doped ◽  
P Type

AbstractIsotopically controlled silicon multilayer structures were used to measure the enhancement of self- and dopant diffusion in extrinsic boron doped silicon. 30Si was used as a tracer through a multilayer structure of alternating natural Si and enriched 28Si layers. Low energy, high resolution secondary ion mass spectrometry (SIMS) allowed for simultaneous measurement of self- and dopant diffusion profiles of samples annealed at temperatures between 850°C and 1100°C. A specially designed ion-implanted amorphous Si surface layer was used as a dopant source to suppress excess defects in the multilayer structure, thereby eliminating transient enhanced diffusion (TED) behavior. Self- and dopant diffusion coefficients, diffusion mechanisms, and native defect charge states were determined from computer-aided modeling, based on differential equations describing the diffusion processes. We present a quantitative description of B diffusion enhanced self-diffusion in silicon and conclude that the diffusion of both B and Si is mainly mediated by neutral and singly positively charged self-interstitials under p-type doping. No significant contribution of vacancies to either B or Si diffusion is observed.

scholarly journals Новый подход к анализу фазового состава углеродсодержащих материалов методом времяпролетной вторично-ионной масс-спектрометрии

2019 ◽  
Vol 45 (2) ◽  
pp. 50
Author(s):  
М.Н. Дроздов ◽  
Ю.Н. Дроздов ◽  
А.И. Охапкин ◽  
С.А. Краев ◽  
М.А. Лобаев
Keyword(s):  
Mass Spectra ◽  
Secondary Ion Mass Spectrometry ◽  
Simple Algorithm ◽  
Cluster Ions ◽  
Two Phase ◽  
Depth Profiles ◽  
Secondary Cluster ◽  
Phase Systems ◽  
Secondary Ion

AbstractNew possibilities offered by the method of secondary ion mass spectrometry (SIMS) for analysis of the phase composition of carbon-containing materials are considered. Differences are established between the mass spectra of three carbon phases: diamond, diamond-like carbon (DLC), and graphite. A simple algorithm for the quantitative determination of different phases in two-phase systems diamond–graphite and DLC–graphite is proposed that is based on the measurement of relative intensities of secondary cluster ions such as C_8/C_5 and CsC_8/CsC_4. It is shown that nonuniform depth profiles of various carbon phases are formed in diamond structures upon laser cutting and in DLC structures upon thermal annealing.

Determination of the Distribution of Ion Implantation Boron in Silicon

2000 ◽  
Vol 650 ◽  
Author(s):  
Te-Sheng Wang ◽  
A.G. Cullis ◽  
E.J.H. Collart ◽  
A.J. Murrell ◽  
M.A. Foad
Keyword(s):  
Electron Microscopy ◽  
Secondary Ion Mass Spectrometry ◽  
Low Energy ◽  
Concentration Profiles ◽  
Impurity Profile ◽  
Transmission Electron ◽  
Device Applications ◽  
P Type ◽  
Secondary Ion

ABSTRACTBoron is the most important p-type dopant in Si and it is essential that, especially for low energy implantation, both as-implanted B distributions and those produced by annealing should be characterized in very great detail to obtain the required process control for advanced device applications. While secondary ion mass spectrometry (SIMS) is ordinarily employed for this purpose, in the present studies implant concentration profiles have been determined by direct B imaging with approximately nanometer depth and lateral resolution using energy-filtered imaging in the transmission electron microscopy. The as-implanted B impurity profile is correlated with theoretical expectations: differences with respect to the results of SIMS measurements are discussed. Changes in the B distribution and clustering that occur after annealing of the implanted layers are also described.

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