In this work we analyzed the radiation hardness of SiC p+ n diodes used as minimum ionizing particle (MIP) detectors after very high 1 MeV neutron fluences. The diode structure is based on ion implanted p+ emitter in an n-type epilayer with thickness equal to 55 mand donor doping = 2x10^{14}cm^3. The diode breakdown voltages were above 1000 V. At 1000 V the leakage currents are of the order of 1 nA for all the measured diodes. The full depletion voltage is near 220–250 V. The charge collection efficiency to minimum ionizing particle has been investigated by a 90Sr source. At 250 V the collected charge of the unirradiated diodes saturates near 3000 e . At bias voltages over 100 V the energy spectrum of the collected charge was found to consist of a signal peak well separated from the noise. At around 250 V the signal saturates, in agreement with CV results. These devices have been irradiated at 6 different fluences, logarithmically distributed in the range 1014–1016 (1 MeV) neutrons/cm2. The leakage current after irradiation decreases. The collected charges decrease for increasing fluences, remaining very high only until some 10^{14} n/cm^2.
Radiation Hardness After Very High Neutron Irradiation of Minimum Ionizing Particle Detectors Based on 4H-SiC p+n Junctions
SCORZONI, Andrea;
2006
Abstract
In this work we analyzed the radiation hardness of SiC p+ n diodes used as minimum ionizing particle (MIP) detectors after very high 1 MeV neutron fluences. The diode structure is based on ion implanted p+ emitter in an n-type epilayer with thickness equal to 55 mand donor doping = 2x10^{14}cm^3. The diode breakdown voltages were above 1000 V. At 1000 V the leakage currents are of the order of 1 nA for all the measured diodes. The full depletion voltage is near 220–250 V. The charge collection efficiency to minimum ionizing particle has been investigated by a 90Sr source. At 250 V the collected charge of the unirradiated diodes saturates near 3000 e . At bias voltages over 100 V the energy spectrum of the collected charge was found to consist of a signal peak well separated from the noise. At around 250 V the signal saturates, in agreement with CV results. These devices have been irradiated at 6 different fluences, logarithmically distributed in the range 1014–1016 (1 MeV) neutrons/cm2. The leakage current after irradiation decreases. The collected charges decrease for increasing fluences, remaining very high only until some 10^{14} n/cm^2.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
