Charge trapping in high K gate dielectric stacks

Abstract

Charge trapping in Al2O3 and HfO2 nFETs is studied. The dependence of threshold voltage, sub-threshold slope and gate leakage currents are investigated as a function of stressing time, voltage and temperature. Based on the experimental data, a model is developed for predicting threshold voltage shifts as a function stressing time. The model is compatible with both Al2O3 and HfO2 data. Using the model, threshold voltage shifts after 10 years of stressing is predicted and trapping capture cross sections are estimated. A comparison between Al2O3 and HfO2 is also made.