Analysis of Wake-Up Reversal Behavior Induced by Imprint in La:HZO MFM Capacitors

Abstract

This article focuses on in-depth examina-tion of the imprint effect in lanthanum-doped Hf0.5Zr0.5O2 (La:HZO) capacitors. The first part shows the imprint effect in a single positive up negative down (PUND) measurement caused by different delays between pulses. In addition, a unique wake-up reversal behavior (i.e., current peak split in the I -V curve and pinched P -V loop) induced by imprint has been investigated in devices with two different pre-polarized states (positive and negative). The results have shown that this behavior is accelerated by the bake temper-ature. Quantitative evaluation of the observed current peak split at each bake time and bake temperature yielded acti-vation energy, suggesting that the wake-up reversal is due to oxygen vacancy redistribution. Moreover, correspond-ing models explaining how these charged defects and the polarization dipoles interact at each measurement step are proposed. Lastly, analysis of temperature-dependent field cycling characteristics suggests that the degraded wake-up of La:HZO film at high temperature can be attributed to the wake-up reversal effect being concurrent with wake-up.