Nuclear radiation detectors using thick amorphous-silicon MIS devices

Metal insulator semiconductor (MIS) devices made from hydrogenated amorphou s silicon (a-Si:H) were developed for the detection of charged particles. D evices with a Cr/a-SiNx:H/a-Si:H structure and with varying thicknesses fro m 3 to 20 mum (a-Si:H layer) were fabricated using the radio-frequency plas ma enhanced chemical vapour deposition (PECVD) technique. They were used fo r the detection of alpha particles (E = 5.5 MeV, Am-241 source) and low-ene rgy beta particles (E <;156 keV, C-14). The characteristics of the MIS dete ctors were compared to that of PIN diodes made using the same PECVD apparat us and processes. MIS detectors appeared to be well suited for the detectio n of charged particles, with better properties than that of PIN diodes for low-energy alpha particle detection (E <;2 MeV). MIS devices were shown to be a very interesting alternative to the commonly used PIN diodes, as they rely on a more straightforward fabrication process and setup, that in parti cular avoids the use of hazardous doping gases such as phosphine. (C) 2001 Elsevier Science B.V. All rights reserved.