High Performance On-Chip Energy Storage Capacitors with Plasma-Enhanced Atomic Layer-Deposited Hf_0.5Zr_0.5O₂/Al-Doped Hf_0.25Zr_0.75O₂ Nanofilms as Dielectrics

Concurrently achieving high energy storage density (ESD) and efficiency has always been a big challenge for electrostatic energy storage capacitors. In this study, we successfully fabricate high-performance energy storage capacitors by using antiferroelectric (AFE) Al-doped Hf0.25Zr0.75O2 (HfZrO:Al) dielectrics together with an ultrathin (1 nm) Hf0.5Zr0.5O2 underlying layer. By optimizing the Al concentration in the AFE layer with the help of accurate controllability of the atomic layer deposition technique, an ultrahigh ESD of 81.4 J cm(-3) and a perfect energy storage efficiency (ESE) of 82.9% are simultaneously achieved for the first time in the case of the Al/(Hf + Zr) ratio of 1/16. Meanwhile, both the ESD and ESE exhibit excellent electric field cycling endurance within 10(9) cycles under 5 similar to 5.5 MV cm(-1), and robust thermal stability up to 200 degrees C. Thus, the fabricated capacitor is very promising for on-chip energy storage applications due to favorable integratability with the standard complementary metal-oxide-semiconductor (CMOS) process.