Wafer-Scale Titanium Niobium Oxide Thin Films Exhibiting In-Plane Ferroelectricity and Antiferroelectricity for High-Performance Nanoelectronics

Titanium niobium oxide (TNO) thin films were deposited on Si, Al 2 O 3 /Si, and HfO 2 /Si substrates and thoroughly characterized using Raman spectroscopy, atomic force microscopy (AFM), x-ray photoelectron spectroscopy (XPS), reflection electron energy loss spectroscopy (REELS), x-ray diffraction (XRD), scanning electron microscopy (SEM), and electrical measurements. TNO is identified as a wide-bandgap semiconductor (≈ 3.8 eV) that exhibits in-plane ferroelectricity on Si and Al 2 O 3 /Si, and antiferroelectricity on HfO 2 /Si—phenomena not previously reported for this material. These properties were confirmed for TNO thin films grown at wafer scale, with remanent polarization exceeding 30 μC cm −2 and coercive fields below 0.5 MV cm −1 . To demonstrate device-level functionality, back-gated transistors were fabricated incorporating TNO as the channel, achieving drain current above 5 mA at gate voltage of only a few volts. The combination of wafer-scale compatibility, stable in-plane polarization, structural robustness, and high-performance transistor operation positions TNO as a versatile platform for next-generation nanoelectronics, including nonvolatile memory devices, sensors, and neuromorphic computing.