Enhancement of both dielectric and ferroelectric performances in TiN/Al2O3/Hf1-Zr O2/TiO2/TiN -based 3D capacitors

CMOS-compatible HfO 2 -based materials can be used as capacitor materials in dynamic and ferroelectric random-access memories (DRAM and FeRAM). It is a big challenge to achieve both high dielectric constant ( κ ) and ferroelectricity in HfO 2 -based films through existing CMOS-compatible technology, so as to meet the requirements of both DRAM and FeRAM capactiors. In this study, by manipulating Hf/Zr ratio and inserting the Al 2 O 3 and TiO 2 layers, a high κ (∼42@10 kHz) morphotropic phase boundary (MPB) structured Hf 0.5 Zr 0.5 O 2 (HZO, ∼6.2 nm) film with low leakage current (5.1×10 -8 A/cm 2 at 0.6 V) is achieved, meeting the material requirements of DRAM. After 10 5 cycles woken up, a good ferroelectricity can be obtained with 2 P r ∼ 40 μC/cm 2 and coercive field ∼1.22 MV/cm. For the endurance test, the HZO capacitor can maintain switched polarization value >10 μC/cm 2 exceeding 10 11 cycles, which can be used as FeRAM capactior. Finally, the above strategies are utilized to prepare 3D HZO pillar capacitors using the DRAM production line, and both the high- κ MPB structure and good ferroelectric properties are realized as well.