使用反应分子动力学模拟碳化硅的原子去除机理

Simulation of atomic removal mechanism of silicon carbide using reactive molecular dynamics

为了分析羟基自由基水溶液中金刚石抛光碳化硅过程中材料原子级别的去除机理,采用反应分子动力学对抛光过程进行了模拟.结果表明:羟基自由基和水分子吸附在碳化硅表面,浸入到碳化硅表面并与Si原子和C原子成键,实现碳化硅基体的氧化;在磨粒机械作用下,工件的Si原子主要以SiO、SiO2或Si链的形式去除,C原子主要以CO、CO2形式去除;抛光压力越大,工件表面吸附的原子数越多,工件去除的原子越多;抛光速度过大,基体与溶液反应时间缩短,导致工件原子去除量小,表明从工件上去除原子是化学反应和机械作用的结果.

In order to analyze the removal mechanism of materials at atomic level in the silicon carbide polishing process with diamond in the hydroxyl radical aqueous solution,reactive molecular dynamics was employed to simulate the polishing process.The results show that hydroxyl radicals and water molecules are adsorbed on the surface of silicon carbide and immersed in the surface of silicon carbide,and form bonds with Si and C atoms to achieve matrix oxidation.Under the mechanical action of abrasive grains,the Si atoms in workpieces are removed mainly in the forms of SiO,SiO2 or Si chain,and the C atoms are removed mainly in the forms of CO and CO2.The greater the polishing pressure,the more the atoms adsorbed on the surface of workpieces,the more the atoms removed from the workpieces.When the polishing speed is too large,the reaction time between matrix and solution is shortened,resulting in small atomic removal amount of workpieces and indicating that the removal of atoms from workpieces is resulting from chemical reaction and mechanical action.