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Alpha radiation induced space charge stability effects in semi-insulating silicon carbide semiconductors compared to diamond.

Hodgson, M, Lohstroh, Annika and Sellin, Paul (2017) Alpha radiation induced space charge stability effects in semi-insulating silicon carbide semiconductors compared to diamond. Diamond and Related Materials, 78. pp. 49-57.

Hodgson-Paper-151010-6_0b - SiC-SI Polarisation (DRM) - Revision.pdf - Accepted version Manuscript

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Although the use of semi-insulating silicon carbide material for radiation detection purposes has been previously demonstrated, its use in practical applications has been inhibited by space charge stability issues caused by defect concentrations within the material, the so called polarisation effect, by which the count rate and resultant spectrum changes with irradiation time. This is a result of the charge carriers generated during irradiation filling deep level defects within the material, causing space charge buildup and de-activating that trap level until the trapped charge is re-emitted. Consequently, the time dependence of the polarisation effect has been determined by a combination of parameters that can be influenced during operation, namely the incident radiation intensity, ambient light, temperature and bias. The material properties have also been considered through the use of materials with different defect capture cross sections, concentrations and energy level. A thorough characterisation of the alpha irradiation induced polarisation phenomenon in semi-insulating silicon carbide has been conducted to demonstrate that stable operation detectors are in fact possible with this material. The effects were compared to single crystal diamond and polycrystalline diamond, which are known to exhibit similar polarisation issues. The polarisation rate as an effect of incident flux, bias and temperature was determined, with the depolarisation rate as a function of ambient light and bias also demonstrated. Consequently it has been shown that stable operation can be maintained for detectors made from semi-insulating SiC material of active thickness 350 μm at incident alpha radiation fluxes of < 0.7 alphas per second per mm2 with high operating biases (> ±400 V). Furthermore, polarisation can be suitably managed or reduced through the use of light illumination and elevated temperatures (373 K).

Item Type: Article
Divisions : Faculty of Engineering and Physical Sciences > Physics
Authors :
Hodgson, M
Date : 20 July 2017
DOI : 10.1016/j.diamond.2017.07.010
Copyright Disclaimer : © British Crown Owned Copyright 2017/AWE. Crown Copyright © 2017 Published by Elsevier B.V. All rights reserved. This manuscript version is made available under the CC-BY-NC-ND 4.0 license
Uncontrolled Keywords : Semi-Insulating Silicon Carbide, Single Crystal Diamond, Polycrystalline Diamond, Irradiation stability, Polarization, Temperature dependance
Depositing User : Melanie Hughes
Date Deposited : 09 Aug 2017 11:06
Last Modified : 20 Jul 2018 02:08

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