Low-temperature field ionization of localized impurity levels in semiconductors

The dynamics of field ionization from localized impurity levels in a semiconductor at low temperatures in an externally applied electric field are studied. The theory predicts a pronounced peak, characteristic of the impurities present and their state of ionization in the I-V curves of devices containing a uniform lightly doped region sandwiched between surface electrodes, provided that the applied voltage is swept sufficiently rapidly. The results of the theory are found to be in good agreement with experiments using silicon pin diodes.