Physical model for frequency-dependent dynamic charge trapping in metal-oxide-semiconductor field effect transistors with HfO 2 gate dielectric

Abstract

In this letter, we report on a physical model to explain the frequency dependence of dynamic charge trapping in metal-oxide-semiconductor (MOS) transistors with ultrathin HfO 2 gate dielectrics. For transistors operating in a complementary MOS inverter circuit with a given gate voltage amplitude, we observed a reduction of charge trapping when the stress frequency is increased. This can be explained by the traps in the high-k HfO 2 dielectric have the property of negative-U centers. One trap can capture two electrons sequentially, and the trap energy is reduced as a result of lattice relaxation. Results of calculation using the model show excellent agreement with all experiment data. © 2005 American Institute of Physics.