The influence of high-energy electrons irradiation on the electrical properties of Schottky barrier detectors based on semi-insulating GaAs

Abstract

In this work we fabricated detectors based on semi-insulating GaAs and studied their electrical properties (current-voltage characteristics, galvanomagnetic measurements) after irradiation with 5 MeV electrons from a linear accelerator up to a dose of 104 kGy. A series of detectors were prepared using Ti/Pt/Au Schottky contact with 1 mm diameter. The thickness of the base material was about 230 µm. A whole area Ni/AuGe/Au ohmic contact was evaporated on the back side. For galvanomagnetic measurements we used three samples from the same wafer. All samples were irradiated by a pulse beam of 5 MeV electrons using the linear accelerator in 11 steps, where the accumulative dose increased from 1 kGy up to 104 kGy. Also different dose rates (20, 40 and 80 kGy/h) were applied to the samples. After each irradiation step we performed electrical measurement of each sample. We analyze the electron Hall mobility, resistivity, electron Hall concentration, breakdown voltage and reverse current of samples before and after irradiation using different dose rates. K: Radiation damage to detector materials (solid state); Solid state detectors; Materials for solid-state detectors 1Corresponding author.

Spreading of an active region of semi-insulating GaAs detectors after radiation degradation

“…The semi-insulating GaAs is a very compensated material where the insertion of point defects from electron irradiation alters the bulk resistivity. In our previous works on the irradiation of GaAs detectors with high energy electrons we have investigated the vacancy density, the resistivity and the Hall mobility of electrons with increasing irradiation dose [14,20,21]. In [20] we evaluated the resistivity and electron mobility of SI GaAs material for irradiation doses up to 104 kGy using galvanomagnetic measurements.…”

“…In our previous works on the irradiation of GaAs detectors with high energy electrons we have investigated the vacancy density, the resistivity and the Hall mobility of electrons with increasing irradiation dose [14,20,21]. In [20] we evaluated the resistivity and electron mobility of SI GaAs material for irradiation doses up to 104 kGy using galvanomagnetic measurements. The resistivity initially decreased slightly with dose from a value of 1.9×10 7 Ωcm to 1.8×10 7 Ωcm at 24 kGy and then began a monotonic increase to a level of 2.5×10 7 Ωcm at a dose of 104 kGy.…”

Spectrometric properties of semi-insulating GaAs detectors irradiated by 5 MeV electrons at different dose rates

“…Afanaciev et al in [4] irradiated the Cr-doped GaAs sensors by 10 and 8.5 MeV electron beam by a dose rate of 20 to 400 kGy/h to a total dose of 1.5 MGy and observed the charge collection efficiency (CCE) degradation with the absorbed dose. We have also studied the radiation hardness of GaAs detectors against high-energy electrons in our previous research [5][6][7][8]. In [5] we have noticed slight changes of the spectrometric properties at low doses (5 to 10 kGy) but the detector properties were rather poor, caused by the Schottky contact topology.…”

“…The future electron-positron collider planned in Europe [3] will be exposed to electron-positron pairs from bremsstrahlung of a dose of about 1 MGy per year. There are very few studies dealing with radiation resistance of GaAs detectors against high-energy electrons [4][5][6][7][8]. Afanaciev et al in [4] irradiated the Cr-doped GaAs sensors by 10 and 8.5 MeV electron beam by a dose rate of 20 to 400 kGy/h to a total dose of 1.5 MGy and observed the charge collection efficiency (CCE) degradation with the absorbed dose.…”

Facile activation of a GaAs substrate with electron beam irradiation for THz photoconductive antenna

“…Therefore, only a very tiny amount of point defects could be created in a single collision event. 28) As such, we expect that an extremely harsh electron beam irradiation condition would be needed in order to achieve a defect introduction effect at the level comparable to LT-GaAs or ion-implanted GaAs.…”