Wafer-scale uniform non-ferroelectric κ-phase In₂Se₃ transistors.

Abstract

Two-dimensional (2D) indium selenide (In₂Se₃) has great potential for next-generation processing-in-memory applications owing to high intrinsic carrier mobility and strong ferroelectricity. However, the lack of wafer-scale, back-end-of-line (BEOL) compatible growth and inherent polarization-induced hysteresis limit their viability in logic circuits. Here, we report thermal evaporation of a non-ferroelectric κ-phase In₂Se₃ film that forms uniformly over 4-inch wafer-scale at <450 °C. Structural characterization confirms underexplored κ-phase formation with an indirect bandgap of 1.45 eV and n-type conduction. The unique atomic arrangement suppresses spontaneous polarization, eliminating hysteresis in field-effect transistors (FETs). The κ-In₂Se₃ FETs exhibit enhancement-mode operation, high field-effect mobility of 39.3 cm² V⁻¹ s⁻¹, and stable switching over 1000 cycles, enabled by reduced trap states and contact resistance. By integrating κ-In₂Se₃ with a p-type selenium-alloyed tellurium oxide FET, we demonstrate a complementary inverter with full-swing operation and high voltage gain. These results establish κ-In₂Se₃ as a scalable 2D semiconductor platform for BEOL-compatible logic integration.