Study on OH radical oxidation of 4H-SiC in plasma based on ReaxFF molecular dynamics simulation

Abstract

The application of hydroxyl (OH) radicals to promote chemistry during the polishing of the SiC substrates has received increasing attention from researchers. Compared to catalyzing OH radicals in solution, catalyzing OH radicals in the gaseous state have faster speed and more environmentally friendly generation. In this study, a stable OH radical plasma jet was generated for the oxidation modification of 4H-SiC surface, by excitation and ionizing water molecules in plasma. The deposition of OH radicals on the 4H-SiC surface was simulated with ReaxFF molecular dynamics to study the nanoscale oxidation mechanism. The experimental results demonstrate that the OH radical can achieve surface oxidation of 4H-SiC, thus effectively reducing the hardness. The simulation results revealed that the deposition of OH radicals on the 4H-SiC surface generated varieties of different reaction processes, such as adsorption, dissociation, decomposition, rebound, collision, and injection. The OH radical deposition rate and substrate temperature determine the reaction process. The results of this study provide theoretical support for further revealing the mechanism of action of OH radicals on 4H-SiC and for realizing efficient plasma-assisted polishing.