Semi-Insulating Gallium Arsenide (SI-GaAs) devices have been tested for radiation hardness with 3-4 MeV or 24 GeV proton beams. These devices can be operated in dc mode as optically activated electrical switches up to 1 kV. Both single switches (vertical Schottky diodes) and multiple (8) switches (planar devices) have been studied, by analyzing their current-voltage (I-V) reverse characteristics in the dark and under red light illumination, both before and after irradiation. We propose to use them in the system of high-voltage (-600 V) switches for the microstrip gas chambers for the CMS experiment at CERN. Low energy protons (3-4 MeV) were used in order to produce a surface damage below the Schottky contact: their fluence (up to 2.6×1015 p/cm2) gives a high-dose irradiation. The high energy proton irradiation (energy: 24 GeV, fluence: 1.1×1014 p/cm2) reproduced a ten years long proton exposure of the devices in CMS experiment conditions. For low energy irradiation, limited changes of the I-V curves in the dark have been observed, with at most a fourfold increase of the leakage current: after exposure, however, the breakdown voltage decreases significantly. For high energy irradiation, we observed-for the vertical Schottky diodes biased at -600 V-an increase of the leakage current and a reduction of the photocurrent after irradiation, with respect to pre-irradiation conditions. For these diodes, the reduction of the photocurrent/dark current ratio was 25:1. At the same proton energy, an analogous behaviour was shown by the planar devices, but after irradiation the current gain may reduce over three orders of magnitude
Irradiation of optically activated SI-GaAs high voltage switches with low and high energy protons / Bertolucci, Ennio; Conti, Maurizio; Mettivier, Giovanni; Russo, Paolo; Mg, Bisogni; U., Bottigli; Me, Fantacci; A., Stefanini; A., Cola; F., Quaranta; L., Vasanelli; G., Stefanini. - In: IEEE TRANSACTIONS ON NUCLEAR SCIENCE. - ISSN 0018-9499. - 49:3(1999), pp. 121-125. (Intervento presentato al convegno 1998 IEEE Nuclear Science Symposium and Medical Imaging Conference nel 8-14/11/1998) [10.1109/23.775500].
Irradiation of optically activated SI-GaAs high voltage switches with low and high energy protons
BERTOLUCCI, ENNIO;CONTI, MAURIZIO;METTIVIER, GIOVANNI;RUSSO, PAOLO;
1999
Abstract
Semi-Insulating Gallium Arsenide (SI-GaAs) devices have been tested for radiation hardness with 3-4 MeV or 24 GeV proton beams. These devices can be operated in dc mode as optically activated electrical switches up to 1 kV. Both single switches (vertical Schottky diodes) and multiple (8) switches (planar devices) have been studied, by analyzing their current-voltage (I-V) reverse characteristics in the dark and under red light illumination, both before and after irradiation. We propose to use them in the system of high-voltage (-600 V) switches for the microstrip gas chambers for the CMS experiment at CERN. Low energy protons (3-4 MeV) were used in order to produce a surface damage below the Schottky contact: their fluence (up to 2.6×1015 p/cm2) gives a high-dose irradiation. The high energy proton irradiation (energy: 24 GeV, fluence: 1.1×1014 p/cm2) reproduced a ten years long proton exposure of the devices in CMS experiment conditions. For low energy irradiation, limited changes of the I-V curves in the dark have been observed, with at most a fourfold increase of the leakage current: after exposure, however, the breakdown voltage decreases significantly. For high energy irradiation, we observed-for the vertical Schottky diodes biased at -600 V-an increase of the leakage current and a reduction of the photocurrent after irradiation, with respect to pre-irradiation conditions. For these diodes, the reduction of the photocurrent/dark current ratio was 25:1. At the same proton energy, an analogous behaviour was shown by the planar devices, but after irradiation the current gain may reduce over three orders of magnitudeI documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
