Effect of the defect clusters on the mobility in neutron-irradiated p-type silicon

The carrier scattering due to the defect clusters in neutron-irradiated p-type silicon was studied. The spherical cluster model was found to be inadequate to explain the carrier scattering in neutron-irradiated p-type silicon. So, we presented the model about the cluster scattering on the basis of the empirical relation, which is called ''empirical model''. The scattering cross section per defect cluster A sub(e) and per defect S sub(e) in the empirical model were much larger than those in the spherical mode, respectively. S sub(e) was one to two orders of magnitude larger than the scattering cross section per singly charged center. A sub(e) and S sub(e) did not depend on the oxygen concentration and Cu-contamination but only on the acceptor concentration. The acceptor concentration dependence of A sub(e) was not so simple as the spherical model expected. The temperature dependence of the mobility after neutron irradiation in the empirical model was in good agreement with the experimental results over the measurement temperature range 103-3220K in the resistivity range 1-135 ohm-cm. On the other hand, the mobility by the spherical model deviated considerably from the experimental results, especially in the low temperature range. The mobility due to the cluster scattering in the empirical model slightly depended on the temperature and had a tendency to saturate as the temperature decreased in the temperature range 103-1570K, while it depended on Tsup(-0.60) in the temperature range 164-3220K, which could be explained qualitatively by the cluster-space charge region model. This situation was not true for the spherical model. (auth.)