Investigating charge trapping in ferroelectric thin films through transient measurements

TL;DR

This paper introduces a measurement technique to analyze charge trapping effects in ferroelectric thin films by observing polarization loss over time, providing insights into the dynamics of charge trapping and screening.

Contribution

A novel transient measurement method is developed to quantify polarization loss and investigate charge trapping in ferroelectric thin films, supported by experimental data on Hf0.5Zr0.5O2 and HZO/Al2O3.

Findings

Charge trapping causes Gaussian dependence of polarization loss rate on delay time.

A charge trapping and screening model explains short-term polarization dynamics.

Experimental results show effects of pulse width and temperature on polarization loss.

Abstract

A measurement technique is presented to quantify the polarization loss in ferroelectric thin films as a function of delay time during the first 100s after switching. This technique can be used to investigate charge trapping in ferroelectric thin films by analyzing the magnitude and rate of polarization loss. Exemplary measurements have been performed on Hf0.5Zr0.5O2 (HZO) and HZO/Al2O3 films, as a function of pulse width and temperature. It is found that the competing effects of the depolarization field, internal bias field and charge trapping lead to a characteristic Gaussian dependence of the rate of polarization loss on the delay time. From this, a charge trapping and screening model could be identified which describes the dynamics of polarization loss on short timescales.