Ferroelectric-HfO₂/oxide interfaces, oxygen distribution effects, and implications for device performance

Atomic-scale understanding of HfO2 ferroelectricity is important to help address many challenges in developing reliable and high-performance ferroelectric (fe-HfO2) based devices. Though investigated from different angles, a factor that real device-relevant clearly deserves more attention has largely been overlooked by previous research, namely, the fe-HfO2/dielectric interface. Here, we investigate electronic structures several typical interfaces formed between ultrathin fe-HfO2 oxide dielectrics sub-3-nm region. We find interface formation introduces strong depolarizing fields fe-HfO2, which detrimental for polarization but can be merit if tamed tunneling devices, as recently demonstrated. Asymmetric oxygen distribution-induced polarity, intertwined with or not, also relevant interfacial effect device. considered certain aspects, such inducing build-in field (independent polarization) exacerbating depolarization (intertwined polarization), it partly balanced out other effects, annealing (extrinsic) polarity-induced defect (intrinsic). This work provides insights into ferroelectric-HfO2/dielectric some useful implications development