Permanent Radiation Damage Effects in Narrow-Base PNPN Devices

The effects of fast-neutron radiation damage in narrow-base PNPN devices were measured and compared with a simple, one-dimensional theory for PNPN devices, based on the work of Kuz\´min. The limitations of a PNPN device in a radiation environment are primarily determined by the increased forward "on" voltage. A reasonably good fit of observed and calculated "on" voltages for a variety of PNPN\´s was obtained using a silicon lifetime damage constant of ¿106 sec-N/cm2. Design considerations for radiation-resistant PNPN\´s are discussed, and devices capable of operating after exposure to more than 1015 neutrons/cm2 are described. PNPN\´s are shown to be superior to bipolar transistors as power switches in a radiation environment.