The effects of biaxial stress in hafnium zirconium oxide (HZO) thin films on the phase constitution and dielectric response are studied through the preparation of HZO films on substrates with coefficients of thermal expansion (CTE) ranging from 0.52 to 12.97 × 10−6 K−1. X-ray diffraction-based stress measurements revealed a systematic decrease in film biaxial tensile stress with increasing substrate CTE. Grazing incidence and attenuated total reflectance Fourier transform infrared spectroscopy revealed spectral energy shifts that scale with film stress, proving vibrational spectroscopy as an additional indicator of film stress. Ferroelectric responses are observed in HZO prepared on low CTE substrates, and antiferroelectric-like responses are observed in films on high CTE substrates. Results indicate that reducing substrate CTE increases tensile biaxial stress and results in higher fractions of the metastable polar orthorhombic phase. High substrate CTE values lead to low HZO stress values and spectroscopic and antiferroelectric responses consistent with the presence of the antipolar o-I phase.
Publications
2026
Qureshi, N. T.; Ferasat, M.; Johnson, L.; Aronson, B. L.; Choi, Y. K.; Lam, N. K.; Lenox, M. K.; Hachtel, J. A.; Shukla, N.; Beechem, T. E.; et al. Correlating biaxial stress to metastable phases in Hf0.5Zr0.5O2 on substrates with different coefficients of thermal expansion. Applied Physics Letters 2026, 129, 142901.
Silvis, A. R.; Hauer, K. M.; Dickie, D. A.; Machan, C. W. CCDC 2283925: Experimental Crystal Structure Determination. CSD Communication 2026.
Obi, A. D.; Dickie, D. A.; Gilliard Jr., R. J. CCDC 2190047: Experimental Crystal Structure Determination. CSD Communication 2026.
Obi, A. D.; Dickie, D. A.; Gilliard Jr., R. J. CCDC 2190031: Experimental Crystal Structure Determination. CSD Communication 2026.
Obi, A. D.; Dickie, D. A.; Gilliard Jr., R. J. CCDC 2190030: Experimental Crystal Structure Determination. CSD Communication 2026.
Taylor, C. C.; Frey, N. C.; Dickie, D. A.; Gilliard Jr., R. J. CCDC 2441185: Experimental Crystal Structure Determination. CSD Communication 2026.
Taylor, C. C.; Frey, N. C.; Dickie, D. A.; Gilliard Jr., R. J. CCDC 2441184: Experimental Crystal Structure Determination. CSD Communication 2026.
Taylor, C. C.; Frey, N. C.; Dickie, D. A.; Gilliard Jr., R. J. CCDC 2441183: Experimental Crystal Structure Determination. CSD Communication 2026.
Taylor, C. C.; Frey, N. C.; Dickie, D. A.; Gilliard Jr., R. J. CCDC 2441182: Experimental Crystal Structure Determination. CSD Communication 2026.
Dickie, D. A.; Turnbull, M. M. Octahedral Cu(II) perchlorate complexes of n-methyl-2-pyridones. Journal of Coordination Chemistry 2026, 79, 1546–1566.
Reaction of hexaaquacopper(II) perchlorate with n-methyl-2-hydroxypyridine generated a family of [(n-methyl-2-pyridone)xCu](ClO4)2 complexes: [(3-methyl-2-pyridone)6Cu](ClO4)2 (1), [(4-methyl-2-pyridone)6Cu](ClO4)2 (2), [(5-methyl-2-pyridone)6Cu](ClO4)2 (3), [(5-methyl-2-pyridone)4(H2O)2Cu](ClO4)2.2(5-methyl-2-pyridone) (4), and [(6-methyl-2-pyridone)4Cu(ClO4)2] (5). Variable temperature X-ray structural analysis reveals a mixture of elongation and compression Jahn-Teller or Jahn-Teller-like distortions. Compound 1 undergoes a temperature dependent phase transition from a Jahn-Teller elongated structure to a Jahn-Teller compressed structure.