I. Introduction
The POSITIVE bias temperature instability of the n-type metal–oxide–semiconductor field-effect transistor (n-MOSFET PBTI) is a major reliability concern in modern complementary MOSFET technology with Hf-based gate dielectrics [1]. The threshold voltage shifts to a positive direction due to the buildup of negative charge in the gate dielectrics during n-MOSFET PBTI stress. However, the addition of a top nitride layer as a gate dielectric on was reported to cause a turn-around effect during the avalanche electron injection [2], [3]. The authors previously reported the turn-around effects of under n-MOSFET PBTI stress for gate dielectrics [4]. However, a systematic study on the BTI characteristics, including polarity dependence in both n-MOSFET and p-type MOSFET (p-MOSFET), was not carried out. Therefore, this letter examined the BTI characteristics in both n-MOSFET and p-MOSFET to clarify the mechanism of abnormal behavior. The temperature and gate bias dependence, as well as the stress and recovery characteristics with various sequences of bias application, was examined.