Novel Polymorphs of Hafnium Oxide published in ACS Applied Materials and Interfaces

Our latest work on hafnium oxide, was recently published in ACS Applied Materials and Interfaces. Here we report the identification of two oxygen-deficient polymorphs of hafnium oxide with semiconducting properties, namely the low temperature cubic phase (LTP c-HfO_1.7) and hcp-HfO_0.7, a hexagonal phase with oxygen interstitials. Further, based on our results, we propose a consistent band structure model for the whole oxidation range from metallic hafnium to stochiometric hafnia. While investigations on materials properties of substoichiometric hafnium oxide are scarce, such knowledge is extremely valuable in the context of latest microelectronics-research. Here, hafnium oxide plays a key role for next generation non-volatile resistive or ferroelectric memory and many connected emerging technologies like in-memory processing or neuromorphic „brain-like“ computing.

N. Kaiser, T. Vogel, A. Zintler, S. Petzold, A. Arzumanov, E. Piros, R. Eilhardt, L. Molina-Luna, and L. Alff
Defect-Stabilized Substoichiometric Polymorphs of Hafnium Oxide with Semiconducting Properties
doi: 10.1021/acsami.1c09451
ACS Appl. Mater. Interfaces 14, 1290–1303 (2022)