Inhibiting the imprint effect of the TiN/HZO/TiN ferroelectric capacitor by introducing a protective HfO2 layer

Abstract

Interfacial differences between the Hf0.5Zr0.5O2 (HZO) and the top/bottom electrodes caused by the process sequence could lead to the imprint effect of the TiN/HZO/TiN ferroelectric capacitor, which leads to serious reliability problems. In this article, a method of introducing a HfO2 protective layer is proposed to inhibit the imprint effect of the TiN/HZO/TiN ferroelectric capacitor. By introducing the HfO2 protective layer, the leakage current at the positive electric field is reduced by three orders of magnitude, the asymmetry of the coercive field is reduced from 1.5 to 0.1 MV/cm, and the endurance is improved by two orders of magnitude with no degradation in retention. The proposed method provides a feasible strategy to inhibit the imprint effect of TiN/HZO/TiN ferroelectric capacitors and is more compatible with complementary metal–oxide–semiconductor processes.