Influence of irradiation by 24 GeV protons on the properties of 4H-SiC radiation detectors

We had investigated the effects of the irradiation by 24 GeV protons with the doses from 10(13) cm(-2) up to 10(16) cm(-2) on the properties of radiation detectors fabricated as Schottky diodes on 4H-SiC. Numbers and activities of radionuclides and isotopes produced after the irradiation were analysed. Activities of Be-7 and Na-22 were found to be proportional to the irradiation dose and ranged from 1.3 up to 890 Bq and from 1.9 up to 950 Bq, respectively. The total amount of formed stable isotopes was from 1.2 x 10(11) cm(-2) up to 5.9x 10(13) cm(- 2). 390 days after the irradiation the number of radiated electrons with different energies ranged from 1.0 up to 600 per second, respectively. The contact properties were investigated by means of the current-voltage analysis. At lower irradiation doses a slight decrease of the effective potential barrier height from about 0.74 eV down to < 0.7 eV took place. The reverse current of the diodes grew by up to one order of magnitude. At the doses above 3 x 10(15) cm(-2) opposite changes were observed. Irradiation by up to 1 X 10(16) protons/cm(-2), resulted in the increase of the potential barrier height up to similar to 0.85 eV, followed by the drop of the reverse current by up to two orders of magnitude. The observed effects were explained by the appearance of the disordered material structure because of the high-energy particle bombardment. (c) 2006 Elsevier B.V. All rights reserved.