CARRIER DRIFT MOBILITY STUDY IN NEUTRON-IRRADIATED HIGH-PURITY SILICON

Carrier drift mobility, drift velocity and its saturation value have been studied for silicon p-n junction detectors irradiated to neutron fluence range specific for experiments in the future large colliders. The transient current technique (TCT), which monitors the drift current of externally generated free carriers, has been applied for direct measurements of electron and hole drift velocities in fully depleted p-n junction detectors with resistivity ranging from 300 to 5000 Omega cm. It has been found that neutron radiation up to fluences of about 5 X 10(13) n/cm(2) has little effect on the carrier transport properties, including carrier drift mobilities for both carriers and their saturation velocities, at room temperature and at lower temperatures all the way down to 110 K at which the phonon scattering is sufficiently suppressed. This fact has been discussed in terms of efficiency of scattering by radiation induced defects and disorder regions as compared with that by phonon.