Analysis of worst-case hot-carrier conditions for n-type MOSFET

We analyze the worst-case conditions of hot-carrier induced degradation with our model which is based on the evaluation of the carrier distribution function along the Si/SiO₂ interface, i.e. thorough consideration of carrier transport. The distribution function obtained by means of a full-band Monte-Carlo device simulator is used to calculate the acceleration integral, which controls how effectively the carriers are breaking Si-H bonds. Therefore, we analyze these worst-case conditions using this integral as a criterion. We compare the numerical picture with the experimental one and conclude that the model fits the experimental data rather accurately and confirm that these conditions correspond to the relation V_gs = 0.4V_ds between gate and drain voltages. The simplified treatment of carrier transport using the non-Maxwellian but still analytical distribution function is also discussed. A discrepancy between experimental results and simulations, which occurred while employing this simplified approach, is shown and explained.