Leidenfrost Motion of Water Microdroplets on Surface Substrate: Epitaxy of Gallium Oxide via Mist Chemical Vapor Deposition

Abstract

Abstract It is hypothesized that gravity‐driven sedimentation and gliding of water microdroplets on a substrate surface due to the Leidenfrost effect explain the deposition behaviors of epilayers via mist chemical vapor deposition (mist CVD). The deposition rate, thickness uniformity, and surface morphology are dependent on the velocity, incident angle, incident probability, gliding distance, and the lifetime of the droplets on the surface of the substrate. Practically, the deposition of corundum structured gallium oxide (α‐Ga 2 O 3 ) epilayers on a tilted 2‐inch c ‐plane sapphire substrate validated the hypothesis. A high substrate tilt angle and a low mist stream velocity are favorable for a high deposition rate. In contrast, a low substrate tilt angle and a high mist stream velocity are suitable for high uniformity and stable deposition of the α‐Ga 2 O 3 thin films via mist CVD.