抛光垫及抛光液对固结磨料抛光氧化镓晶体的影响

氧化镓晶体具有高禁带宽度、耐高压、短吸收截止边等优点，是最具代表性的第四代半导体材料之一，具有广阔地应用前景。氧化镓晶体抛光过程易出现微裂纹、划痕等表面缺陷，难以实现高质量表面加工，无法满足相应器件的使用要求，且现有的氧化镓晶体抛光工艺复杂、效率低。固结磨料抛光技术具有磨粒分布及切深可控、磨粒利用率高等优点。采用固结磨料抛光氧化镓晶体，探究抛光垫基体硬度、磨料浓度和抛光液添加剂对被抛光材料去除率和表面质量的影响。结果表明:当抛光垫基体硬度适中为Ⅱ、金刚石磨粒浓度为100%、抛光液添加剂为草酸时，固结磨料抛光氧化镓晶体的材料去除率为68 nm/min，表面粗糙度S_a为3.17 nm。采用固结磨料抛光技术可以实现氧化镓晶体的高效高质量抛光。 

Effect of pad and slurry on fixed abrasive polishing of gallium oxide crystal

Gallium oxide crystal is one of the most representative fourth generation semiconductor materials with the advantages of high band gap, high voltage resistance and short absorption cutoff edge. It has broad application prospects. Micro-cracks, scratches and other surface defects are prone to appear in the polishing process of Gallium oxide crystal, which is difficult to achieve high-quality surface processing and cannot meet the requirements of corresponding devices. Moreover, the existing polishing process of gallium oxide crystal is complex and inefficient. Fixed abrasive polishing technology has the advantages of controllable abrasive distribution and depth of cut, and high utilization rate of abrasive. In this study, fixed abrasive polishing of gallium oxide crystal was adopted, and the effect of matrix hardness, abrasive concentration of polishing pad, the additives of polishing slurry on material removal rate and surface quality were investigated. The results show that when the hardness of the polishing pad is moderate II, the abrasive concentration is 100%, and the slurry additive is oxalic acid, the material removal rate is 68 nm/min and the surface roughness S_a value is 3.17 nm in fixed abrasive polishing of gallium oxide crystal. Fixed abrasive polishing technology can achieve high-efficient and high-quality polishing of gallium oxide crystal.