Application of Neutron Damage Models to Semiconductor Device Studies

A hybrid recombination model has been formulated for neutron irradiated silicon which correctly predicts the minority carrier recombination in both the neutral and space charge regions of a device. Exact, one-dimensional, numerical calculations have been performed using this model and compared to reported V-I characteristics of irradiated p+ n diodes. The calculated curves agree with the reported data within 20% over the seven decade span of currents in the investigations, for diode base resistivities from 0.25 ¿-cm to 17 ¿-cm. At low injection levels the calculated recombination occurs predominantly in the junction space charge region, whereas at high injection both the space charge region and neutral region can be important. Calculations have also been performed for the recombination occurring throughout a typical NPN silicon transistor. The results indicate that space charge region recombination is probably dominant in modern, narrow base transistors even at high injection levels.