Wafer-Scale Bi2O2Se-on-Insulator Thin Films for Integrated Electronics

Abstract

Quasi-2D semiconducting Bi₂O₂Se has emerged as a promising candidate for beyond-silicon electronics due to its outstanding transport performances. However, large-area growth of high-quality Bi₂O₂Se films, which is a critical prerequisite for batch fabrication of electronic devices, remains challenging. Here, we report that wafer-scale growth of Bi₂O₂Se thin films with controllable thicknesses can be achieved on 2-inch insulating sapphire substrates via quasi-van der Waals epitaxy using magnetron sputtering. The obtained films show good spatial uniformity and crystallinity across the wafer, enabling massive fabrication of top-gated Bi₂O₂Se/HfO₂ thin film transistors (TFTs) with reliable n-type enhancement-mode performances, including positive threshold voltages of ∼1.95 V, field-effect mobilities of ∼7.15 cm² V⁻¹ s⁻¹, high on/off current ratios of ∼10⁵, and subthreshold swings of 1.4 V/dec. The integrated inverter, NAND, and NOR logic gates show desired functionalities with high voltage gains of ∼24.7. This study represents a significant step toward the real application of Bi₂O₂Se in TFT display technology and complex integrated electronics in a low-cost, scalable, and industry-compatible manner.