A Comprehensive Study of Transient Characteristics in FeFET Using In-Situ Vt Measurement Method

In ferroelectric FETs (FeFETs), the transient characteristics is a key issue to be addressed. Therefore, it is important to have an understanding based on accurate measurements of transient characteristics. In this work, the in-situ threshold voltage (Vt) measurement method is presented, which allows simultaneous observation of the change of remnant polarization (Pr) and Vt over delay time within a device. This provides insight into the characteristics of both Pr and trapped charge depending on delay time (tdelay). The transient characteristic after applying the positive voltage is particularly important, as electrons are injected from the channel side. Thus, we show that the time to a steady state of program Vt is shortened by controlling the electrons by applying a small negative voltage immediately after the positive voltage.