The dependence of diffusion length, lifetime and emitter Gummel-number on temperature and doping

Abstract

In this paper systematic study of the temperature and doping dependences of the energy gap, the diffusion length, the lifetime and the emitter-Gummel number is presented. Based on a special transistor structure, the above parameters could be measured. The doping concentration in the base varies from 1016/cm3 to 4×1018/cm3 while the temperature changes from 100 K to 340 K. It is found that the band gap narrowing is smaller than that published in some literature while it agrees with that recently published by del Alamo and Swanson [25]. This result is fully discussed and explained in the text. The diffusion length is nearly independent of temperature, which is interesting for device modeling. On the other hand, the diffusion length decreases with the doping concentrationN A . The measured lifetime τ is inversely proportional to doping concentration with powerm wherem=0.6–0.2 depending on temperature. The results show an exponential increase of the emitter Gummel-number with temperature and an increase with doping concentration in the base.