Thermal stability of ferroelectricity in hafnium-zirconium dioxide films deposited by sputtering and chemical solution deposition for oxide-channel ferroelectric-gate transistor applications

Stability of ferroelectricity in hafnium-zirconium oxide (HZO) films deposited by sputtering and chemical solution deposition (CSD) has been investigated. After confirming the ferroelectricity of both sputtered HZO and CSD yttrium-doped HZO (Y-HZO) films, indium-tin-oxide (ITO) was deposited by sputtering on sputtered HZO or CSD Y-HZO layer to fabricate metal-ferroelectric-semiconductor (MFS) structure. It was found that the sputtered HZO films in the MFS structure became paraelectric after re-annealing in N-2 which was confirmed by both X-ray diffraction pattern and electrical measurements. On the other hand, the CSD Y-HZO films showed ferroelectric nature even after re-annealing with a negligible monoclinic phase.

Automated summary

This study investigated the stability of ferroelectricity in HZO films deposited by different methods in MFS structures. Sputtered HZO films lost their ferroelectricity after re-annealing, while CSD Y-HZO films maintained their ferroelectric nature with minimal monoclinic phase.