Wafer-scale uniform epitaxy of transferable 2D single crystals for gate-all-around nanosheet field effect transistors

Abstract

Gate-all-around (GAA) nanosheet field-effect transistors (FETs) with two-dimensional (2D) semiconductor channels surrounded by high-kappa dielectrics show outstanding performance and hold promise for ultimate miniaturization in the post-Moore era. However, the synthesis of uniform wafer-scale 2D GAA nanosheet single crystals on industry-compatible substrates presents a considerable challenge. Herein, we report wafer-scale uniform growth of 2D high-kappa oxide/semiconductor/high-kappa oxide GAA single crystals on r-plane sapphire via buffered van der Waals (vdW) epitaxy. The 2D GAA heterostructures possess atomically flat interfaces, exhibiting superb uniformity and crystallinity across the wafer. Furthermore, the 2D GAA heterostructures can be transferred to diverse substrates owing to the vdW gap within the buffer oxide, leaving a reusable wafer. FETs based on 2D GAA heterostructures demonstrate exceptional performance with on/off ratio and optimal carrier mobility of > 10(6) and 227 cm(2) V--(1) s(-)(1), respectively. The transferable wafer-scale 2D GAA heterostructures provide promising avenues for the fabrication of monolithic three-dimensional integrated circuits and extending Moore's law beyond the limitations of silicon.