HfOx seed-layer functionalization of MoS2 for top-gated HZO FeFETs

Two-dimensional MoS2 is a promising channel material for beyond-silicon memory devices, but its chemically inert van der Waals surface makes the direct atomic layer deposition (ALD) of continuous high-k and ferroelectric gate stacks highly challenging in technologically relevant top-gate architectures. Here, we demonstrate an ultrathin sputtered HfOx seed layer as a scalable surface-functionalization strategy enabling the conventional H2O-based ALD of ferroelectric Hf0.5Zr0.5O2 (HZO) on near-monolayer metalorganic chemical vapor deposition-grown MoS2. The HfOx seed layer strongly improves HZO uniformity, while Raman spectroscopy and x-ray photoelectron spectroscopy indicate no significant structural degradation and only limited oxidation of the ultrathin MoS2 channel. Using this seed-assisted integration scheme, we realize top-gate MoS2 ferroelectric field-effect transistors with low gate leakage currents, efficient channel modulation, and nonvolatile memory operation. These results establish sputtered HfOx seed-layer functionalization as an effective route for the scalable integration of ferroelectric HZO with two-dimensional MoS2 channels in top-gate memory devices.