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Title: Improved performance of GaAs radiation detectors

Abstract

Gallium arsenide (GaAs) offers an attractive choice for room temperature X- and {gamma}-ray detectors. However performance of SI LEC bulk GaAs detectors is at present limited by the short carrier lifetime and by the diode breakdown occurring as soon as the electric field reaches the back ohmic contact. We have shown that ohmic contacts based on ion implantation allowed us to go far beyond the bias voltage necessary to achieve a fully active detector. However the conventional thermal treatments (850 {degrees}C, 30 s) required to anneal the damage induced by ion implantation strongly reduces the electron lifetime in the detector. Alenia has developed two improved processes (RA and RB) which avoid high temperature annealing and the consequent electron lifetime reduction. With the new detectors, in pixel (200x200 {mu}m{sup 2}) configuration, a charge collection efficiency (cce) of 90 % for 59.5 keV X-rays and a FWHM of 3.35 keV has been achieved at room temperature. These features, thickness, applied voltage, cce and FWRM are suitable for application of GaAs pixel detectors in medical imaging. Results obtained with of particles and X-rays at different temperatures and in a wide range of applied bias in detectors made with standard, implantated and improved processesmore » are presented, compared and discussed.« less

Authors:
;  [1];  [2]
  1. Universita di Modena (Italy)
  2. Politecnico di Milano (Italy); and others
Publication Date:
OSTI Identifier:
513006
Report Number(s):
CONF-961123-
TRN: 97:014066
Resource Type:
Conference
Resource Relation:
Conference: Institute of Electrical and Electronic Engineers (IEEE) nuclear science symposium and medical imaging conference, Anaheim, CA (United States), 2-9 Nov 1996; Other Information: PBD: 1996; Related Information: Is Part Of 1996 IEEE nuclear science symposium - conference record. Volumes 1, 2 and 3; Del Guerra, A. [ed.]; PB: 2138 p.
Country of Publication:
United States
Language:
English
Subject:
44 INSTRUMENTATION, INCLUDING NUCLEAR AND PARTICLE DETECTORS; SEMICONDUCTOR DETECTORS; X-RAY SPECTROSCOPY; GAMMA SPECTROSCOPY; PERFORMANCE; GALLIUM ARSENIDES; SCHOTTKY EFFECT

Citation Formats

Nava, F, Vanni, P, and Bertuccio, G. Improved performance of GaAs radiation detectors. United States: N. p., 1996. Web.
Nava, F, Vanni, P, & Bertuccio, G. Improved performance of GaAs radiation detectors. United States.
Nava, F, Vanni, P, and Bertuccio, G. 1996. "Improved performance of GaAs radiation detectors". United States.
@article{osti_513006,
title = {Improved performance of GaAs radiation detectors},
author = {Nava, F and Vanni, P and Bertuccio, G},
abstractNote = {Gallium arsenide (GaAs) offers an attractive choice for room temperature X- and {gamma}-ray detectors. However performance of SI LEC bulk GaAs detectors is at present limited by the short carrier lifetime and by the diode breakdown occurring as soon as the electric field reaches the back ohmic contact. We have shown that ohmic contacts based on ion implantation allowed us to go far beyond the bias voltage necessary to achieve a fully active detector. However the conventional thermal treatments (850 {degrees}C, 30 s) required to anneal the damage induced by ion implantation strongly reduces the electron lifetime in the detector. Alenia has developed two improved processes (RA and RB) which avoid high temperature annealing and the consequent electron lifetime reduction. With the new detectors, in pixel (200x200 {mu}m{sup 2}) configuration, a charge collection efficiency (cce) of 90 % for 59.5 keV X-rays and a FWHM of 3.35 keV has been achieved at room temperature. These features, thickness, applied voltage, cce and FWRM are suitable for application of GaAs pixel detectors in medical imaging. Results obtained with of particles and X-rays at different temperatures and in a wide range of applied bias in detectors made with standard, implantated and improved processes are presented, compared and discussed.},
doi = {},
url = {https://www.osti.gov/biblio/513006}, journal = {},
number = ,
volume = ,
place = {United States},
year = {Tue Dec 31 00:00:00 EST 1996},
month = {Tue Dec 31 00:00:00 EST 1996}
}

Conference:
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