Importance of complex band models in calculation of direct tunneling current through ultra-thin gate oxides

摘要

In the present study, we report the calculation of I-V characteristics for direct tunneling (DT) currents carried by electrons and/or holes, which is measured using a charge separation technique. We consider one-dimensional p{sup}+-Si/SiO{sub}2/n-Si sandwiches. The self-consistent calculation of Poisson and Schrodinger equations is performed to evaluate the band bending in both substrate and gate depletion layers, and the tunneling current is obtained from transfer-matrix method. In addition, we calculate the complex band structure of SiO{sub}2 based on the second-neighbor sp{sup}3s tight-binding model and discuss the accuracy of the empirical DT current models.