Density-gradient analysis of MOS tunneling

The density-gradient description of quantum transport is applied to the ana lysis of tunneling phenomena in ultrathin (<25 <Angstrom>) oxide MOS capaci tors. Both electron and hole tunneling are included in the one-dimensional (1-D) analysis and two new refinements to density-gradient theory are intro duced, one relating to the treatment of Shockley-Read-Hall recombination an d the other a modification of the tunneling boundary conditions to account for the semiconductor bandgap, Detailed comparisons are made with experimen tal current-voltage (I-V) data for samples with both n(+) and p(+) polysili con gates and all of the features of the data are found to be understandabl e within the density-gradient framework, Besides providing new understandin g of these experiments, these results show that the density-gradient approa ch can be of great value for engineering-oriented device analysis in quantu m regimes.