The Integration of High-k Dielectric on Two-Dimensional Crystals by Atomic Layer Deposition

TL;DR

This paper explores the direct atomic layer deposition of high-k dielectric Al2O3 on 2D materials BN and MoS2, analyzing initial growth mechanisms and modeling to optimize the process.

Contribution

It demonstrates the feasibility of ALD on 2D crystals and models the initial growth stages to guide process optimization.

Findings

ALD can directly deposit Al2O3 on BN and MoS2.

Initial ALD cycles are dominated by physical adsorption.

Lennard-Jones potential modeling aids in understanding growth stages.

Abstract

We investigate the integration of Al2O3 high-k dielectric on two-dimensional (2D) crystals of boron nitride (BN) and molybdenum disulfide (MoS2) by atomic layer deposition (ALD). We demonstrate the feasibility of direct ALD growth with trimethylaluminum(TMA) and water as precursors on both 2D crystals. Through theoretical and experimental studies, we found that the initial ALD cycles play the critical role, during which physical adsorption dominates precursor adsorption at the semiconductor surface. We model the initial ALD growth stages at the 2D surface by analyzing Lennard-Jones Potentials, which could guide future optimization of the ALD process on 2D crystals.