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Title: Implantation profile of {sup 22}Na continuous energy spectrum positrons in silicon

Abstract

The implantation profile of positrons emitted from a continuous energy spectrum source of {sup 22}Na in close proximity to a silicon target is modeled. The primary motivation is the use of positron lifetime spectroscopy to characterize layers of defects such as those created by ion irradiation, usually deemed accessible only to techniques which utilize slow positrons. The model combines the Makhov profile, used with considerable success to describe the profile of low energy (<30 keV) monoenergetic positrons, with the well-established, universal {beta}-decay energy spectrum. The success of this approach is verified by measuring the fractions of positrons absorbed in thinned silicon samples. This verification utilizes lifetime measurements performed on silicon in a bilayer sandwich configuration with copper as a backing. The model accounts for the uncertainty in the positron backscattering at the silicon/copper interface. An optimal fit of the model to the experimental data requires that the parameter defining the mean depth of the Makhov profile (usually denoted r) is energy dependent. An example of application is provided in the form of a positron lifetime measurement of defects in silicon introduced by 1.5 MeV proton irradiation. Excellent agreement is found between the lifetime data and those obtained using a slowmore » positron technique.« less

Authors:
; ; ;  [1];  [2]
  1. Department of Engineering Physics, McMaster University, 1280 Main Street West, Hamilton, Ontario, L8S 4L7 (Canada)
  2. (United Kingdom)
Publication Date:
OSTI Identifier:
20982704
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 101; Journal Issue: 4; Other Information: DOI: 10.1063/1.2472645; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; BACKSCATTERING; BETA DECAY; COPPER; CRYSTAL DEFECTS; ENERGY DEPENDENCE; ENERGY SPECTRA; ION IMPLANTATION; IRRADIATION; KEV RANGE 10-100; LIFETIME; MEV RANGE 01-10; POSITRONS; PROTONS; SILICON; SODIUM 22; SPECTROSCOPY

Citation Formats

Foster, P. J., Mascher, P., Knights, A. P., Coleman, P. G., and Department of Physics, University of Bath, Bath, BA2 7AY. Implantation profile of {sup 22}Na continuous energy spectrum positrons in silicon. United States: N. p., 2007. Web. doi:10.1063/1.2472645.
Foster, P. J., Mascher, P., Knights, A. P., Coleman, P. G., & Department of Physics, University of Bath, Bath, BA2 7AY. Implantation profile of {sup 22}Na continuous energy spectrum positrons in silicon. United States. doi:10.1063/1.2472645.
Foster, P. J., Mascher, P., Knights, A. P., Coleman, P. G., and Department of Physics, University of Bath, Bath, BA2 7AY. Thu . "Implantation profile of {sup 22}Na continuous energy spectrum positrons in silicon". United States. doi:10.1063/1.2472645.
@article{osti_20982704,
title = {Implantation profile of {sup 22}Na continuous energy spectrum positrons in silicon},
author = {Foster, P. J. and Mascher, P. and Knights, A. P. and Coleman, P. G. and Department of Physics, University of Bath, Bath, BA2 7AY},
abstractNote = {The implantation profile of positrons emitted from a continuous energy spectrum source of {sup 22}Na in close proximity to a silicon target is modeled. The primary motivation is the use of positron lifetime spectroscopy to characterize layers of defects such as those created by ion irradiation, usually deemed accessible only to techniques which utilize slow positrons. The model combines the Makhov profile, used with considerable success to describe the profile of low energy (<30 keV) monoenergetic positrons, with the well-established, universal {beta}-decay energy spectrum. The success of this approach is verified by measuring the fractions of positrons absorbed in thinned silicon samples. This verification utilizes lifetime measurements performed on silicon in a bilayer sandwich configuration with copper as a backing. The model accounts for the uncertainty in the positron backscattering at the silicon/copper interface. An optimal fit of the model to the experimental data requires that the parameter defining the mean depth of the Makhov profile (usually denoted r) is energy dependent. An example of application is provided in the form of a positron lifetime measurement of defects in silicon introduced by 1.5 MeV proton irradiation. Excellent agreement is found between the lifetime data and those obtained using a slow positron technique.},
doi = {10.1063/1.2472645},
journal = {Journal of Applied Physics},
number = 4,
volume = 101,
place = {United States},
year = {Thu Feb 15 00:00:00 EST 2007},
month = {Thu Feb 15 00:00:00 EST 2007}
}