Radiation hardness measurements on components of a full custom bipolar process

Abstract We present the characterization of various components of the full custom bipolar process SHPi by Tektronix with respect to radiation hardness. The motivation of this work is to design a low-power, low-noise frontend with fast shaping for silicon microstrip detectors. We have tested BJTs ( npn of various size and a lateral pnp ), JFETs, Schottky diodes, implanted resistors and NiChrome resistors. The devices were irradiated to 60 Co dose of up to 5 Mrad in few steps, to fluence of 5.5∗10 13 n cm −2 of neutrons from a spallation source in few steps and to fluence of up to 1.1∗10 14 cm −2 of 650 MeV protons. It allows us to characterize the sensitivity of the devices on both ionization effects and displacement damage. We have measured the radiation effects on the dc parameters and characteristics of all components as well as on noise in npn BJTs of various size considered as candidates for the preamplifier input transistor. The most significant effect which we observe is the decrease of the current gain β in bipolar transistors for low emitter current densities. Both important noise sources, i.e. the shot noise of the collector current and the thermal noise of the base spread resistance are unaffected by irradiation.