Frequency dependent dynamic charge trapping in HfO 2 and threshold voltage instability in MOSFETs

Abstract

In tills paper, we perform the first investigation of biased threshold voltage instability (BTI) in MOSFETs with MOCVD HfO 2 gate dielectrics under both static and dynamic stress. For an ac stress of a given gate voltage amplitude, we observed reduction of BTI degradation with an increase in stress frequency for both n- and p-MOSFETs. A physical model that accounts for two-step procedure of trap activation (de-activation) and carrier capture (emission) in the HfO 2 dielectric under stress is proposed. Simulation results based on the new model shows good agreement with all experiment data.