Physical and Electrical Characterization of Zinc Telluride Thin Films Deposited by Atomic Layer Deposition

Zinc telluride has shown promising properties to replace complex quaternary chalcogenide alloys, such as GeAsSeTe, for Ovonic Threshold Switching (OTS) selector devices in GeSbTe based phase-change memory (PCM) arrays [1,2]. We have recently shown that thin films of ZnTe deposited by Atomic Layer Deposition on platinum also exhibit non-volatile memory behavior when electrically probed with tungsten tips, opening paths for OTS+PCM integration with a single material [3]. In this work we present and discuss XRD characterization, and temperature-dependent electrical resistivity and Hall carrier mobility measurements of ZnTe thin films deposited by Atomic Layer Deposition on different substrates. ZnTe layers deposited on GaAs and sapphire are polycrystalline while those on SiO₂ are amorphous. The resistance of a 600 nm as-deposited ZnTe film on sapphire was ~ 3x10⁵ Ω.cm at room temperature and decreased gradually with heating to ~ 50 Ω.cm at 550 K. Hall mobility measurements only yielded a consistent behavior of the Hall coefficient versus magnetic field between 490 K and 556 K. In this temperature range, the mobility increased from ~ 75 cm²/V.s at 490 K to ~ 197 cm²/V.s at 556 K. The room temperature resistivity after cooling was ~ 10 Ω.cm.<br/>[1] Y. Koo and H. Hwang, Scientific Reports, 8(1), 1-7 (2018).<br/>[2] T. Kim, Y. Kim, I. Lee, D. Lee and H. Sohn, Nanotechnology, 30(13), 13LT01 (2019).<br/>[3] Maksimov, O., Hansen, K., Bhandari, H.B. et al. Novel applications of ZnTe as an ovonic threshold switching and as a phase change material. MRS Advances 8, 173–176 (2023). https://doi.org/10.1557/s43580-023-00508-2