Computational Fluid Dynamics Insights into Chemical Vapor Deposition of Homogeneous MoS2 Film with Solid Precursors

Abstract

In this work, a comprehensive computational fluid dynamics (CFD) investigation to develop an in-depth understanding on the fluid flow to obtain a homogenous deposition of MoS2 thin film is reported. First, the effect of substrate orientations (0, 20, 45, 70, and 90°) was simulated using ANSYS Fluent. The horizontal substrate (0°) showed a non-uniform surface deposition rate (SDR) with relative standard deviation (RSD) of 44.1 %. The non-uniformity gradually reduces with the increase of substrate angles and reaches the lowest for 90° with RSD of 13.1 %. The transient state analysis showed that no growth occurred for the first 8 s, followed by an SDR overshoot and finally reached a steady state >200 s. Next, the effect of horizontal separation distance (d = 1 to 6 cm) between MoO3 and the substrate is investigated. It is find that the Mo/S ratio reduces with the increase of separation distance. For d between 5 and 6 cm, the Mo/S drops by >1000 times and causes the growth environment to switch from Mo to S-rich. This work offers a fast and cost-effective approach to understand the fluid flow and to obtain a homogeneous deposition of MoS2 and other 2D TMD thin films.