Research progress on phase structure regulationstability of hafnium oxide-based ferroelectric thin films

With the development of microelectronics technology, hafnium oxide (HfO2) has become the research focus of new ferroelectric materials because of its compatibility with Si-based semiconductor technology, suitable relative dielectric constant, good thermal and chemical stability and large band gap. HfO2 is a typical material thatwith "phase structure determines performanceproperties, and performanceproperties determines applications". The existence of its ferroelectric properties deriverstems from the fact that the phase structure of thin films is stable in a non-centoral symmetric Pbc21 or Pca21 orthorhombicgonal phase with space point group Pca21. Therefore, the prerequisite forto stabilizinge and improvinge the ferroelectric properties of HfO2 thin films is to regulatestabilize the metastable orthogonal phase of HfO2 in the metastable orthorhombic phase. Taking the regulation mechanism of orthogonal phase, the stability factors of HfO2 orthogonal phase are reviewed and summarized from aspects such as film thickness, doping elements, grain orientation, and electrode materials. FinallyIn this paper, the influencing factors of HfO2 phase regulation are reviewed and the future development of HfO2 thin films is prospected in this paper.