A transferable route to two-dimensional gate-all-around electronics

Abstract

The relentless drive for miniaturization in microelectronics, guided by Moore's Law, is approaching a critical inflection point. Silicon-based transistors are confronting fundamental physical limits at the atomic scale, where issues of power leakage and degraded electrostatic control become increasingly severe. To sustain performance scaling, the semiconductor industry is transitioning to gate-all-around (GAA) nanosheet architectures for sub-2-nanometer technology nodes. A more revolutionary path lies in integrating atomically thin two-dimensional (2D) semiconductors as the channel material within these GAA structures. 2D semiconductors promise superior electrostatic gate control and lower power consumption, and their potential for monolithic three-dimensional integration is essential for extending computational capabilities. However, the grand challenge has been the absence of a scalable, industry-compatible method to synthesize high-quality, uniform 2D semiconductor channels that are seamlessly and conformally encapsulated by high-k gate dielectrics in a GAA configuration. Existing techniques are plagued by interfacial defects, poor uniformity, or intrinsic limitations in achieving dual-sided, wafer-scale integration. Confronting this challenge, a groundbreaking study by Peng et al. reports the wafer-scale, uniform synthesis of single-crystalline 2D high-k dielectric/semiconductor/high-k dielectric GAA heterostructures via an innovative buffered van der Waals epitaxy technique. The core innovation lies in the pre-deposition of a high-k van der Waals buffer oxide (α-Bi2SeO5) on an industry-standard r-plane sapphire substrate. This buffer oxide mitigates the lattice and symmetry mismatch between the substrate and the target 2D semiconductor (Bi2O2Se), enabling epitaxial growth of a uniform, single-crystalline film. Through controlled oxidation, the top layer of Bi2O2Se is transformed into another high-k dielectric (β-Bi2SeO5), forming the sandwich-like GAA heterostructure (β-Bi2SeO5/Bi2O2Se/α-Bi2SeO5) in a single, scalable growth run with atomically sharp interfaces. Comprehensive characterization confirms exceptional uniformity and crystalline quality over 2-inch wafers.

1. Introduction

The relentless drive for miniaturization in microelectronics, guided by Moore's Law, is approaching a critical inflection point. Silicon-based transistors, the workhorse of modern computing, are confronting fundamental physical limits at the atomic scale, where issues of power leakage and degraded electrostatic control become increasingly severe[1]. To sustain the trajectory of performance scaling, the semiconductor industry is transitioning to gate-all-around (GAA) nanosheet architectures for sub-2-nanometer technology nodes[2]. Yet, this represents only an incremental evolution for silicon.

A more revolutionary path lies in integrating atomically thin two-dimensional (2D) semiconductors as the channel material within these GAA structures[3]. 2D semiconductors, with their atomic thickness, promise superior electrostatic gate control and lower power consumption. Their potential for monolithic three-dimensional (3D) integration is essential for extending computational capabilities beyond the limits of traditional silicon scaling[4]. However, the grand challenge has been the absence of a scalable, industry-compatible method to synthesize high-quality, uniform 2D semiconductor channels that are seamlessly and conformally encapsulated by high-k gate dielectrics in a GAA configuration. Existing techniques, such as direct deposition of amorphous oxides on 2D materials[5] or mechanical assembly of van der Waals (vdW) heterostructures[6], are plagued by interfacial defects, poor uniformity, or intrinsic limitations in achieving dual-sided, wafer-scale integration. Therefore, the scalable preparation of single-crystalline 2D GAA heterostructures with atomically clean interfaces stands as a pivotal bottleneck for the future of electronics.