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

This article focuses on in- depth examination of the imprint effect in lanthanum-doped Hf<inline-formula> <tex-math notation="LaTeX">$_{{0}.{5}}$ </tex-math></inline-formula>Zr0.5O2 (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 <inline-formula> <tex-math notation="LaTeX">${I}$ </tex-math></inline-formula>,–<inline-formula> <tex-math notation="LaTeX">${V}$ </tex-math></inline-formula> curve and pinched <inline-formula> <tex-math notation="LaTeX">${P}$ </tex-math></inline-formula>,–<inline-formula> <tex-math notation="LaTeX">${V}$ </tex-math></inline-formula> loop) induced by imprint has been investigated in devices with two different prepolarized states (positive and negative). The results have shown that this behavior is accelerated by the bake temperature. Quantitative evaluation of the observed current peak split at each bake time and bake temperature yielded activation energy, suggesting that the wake-up reversal is due to oxygen vacancy redistribution. Moreover, corresponding 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.