The 67th JSAP Spring Meeting 2020

Presentation information

Oral presentation

Code-sharing Session » 【CS.4】 Code-sharing Session of 6.1 & 13.3 & 13.5

[14p-A303-1~14] 【CS.4】 Code-sharing Session of 6.1 & 13.3 & 13.5

Sat. Mar 14, 2020 1:45 PM - 5:30 PM A303 (6-303)

Norifumi Fujimura(Osaka Pref. Univ.), Eisuke Tokumitsu(JAIST)

4:30 PM - 4:45 PM

[14p-A303-11] Consideration of Charge Injection Effect on the Degradation of Ferroelectric HfO2 during
Bipolar Voltage Cycling

〇(DC)Siri Nittayakasetwat1, Koji Kita1 (1.Univ. of Tokyo)

Keywords:ferroelectric HfO2, charge injection, phase transformation

The degradation of the switchable polarization (Psw) of ferroelectric (FE) HfO2 during bipolar voltage cycling creates a major issue to the operation stability in FE-related devise. Despite the well know fabrication process of FE-HfO2, the degradation mechanism is still remaining unclarified. To push forward this technology into production, we investigate the possible factors contributing to the degradation of FE-HfO2 during dipolar voltage cycling. We characterized the degradation of FE-properties using bipolar voltage cycling and constant DC-bias stress. After the voltage cycling, we found that the dielectric constant of HfO2 (εHfO2) constantly decreased with the decrease in Psw. To evaluate the dominant factors that determine the degradation mechanism, DC-bias stress was performed before measuring the P-V characteristic. We found that the εHfO2 measured both during the voltage cycling and DC-bias stress monotonically decrease in the same trend along with the reduction in Psw. Therefore, we speculate that charge injection is one of the crucial factors that determine the degradation of FE-HfO2 during bipolar voltage cycling. This finding will be valuable to the design of high performance and reliability in any FE-related devices in the future.