深紫外激光对GaN薄膜的激光抛光研究

为了研究157nm深紫外激光的激光抛光加工特性,采用小光斑对GaN半导体薄膜进行了微平面扫描刻蚀.通过探讨激光工艺参量与激光抛光质量的影响关系,得到了最佳的工艺参量范围.结果表明,随着激光抛光扫描速率的增加,材料加工表面粗糙度值Ra逐渐减小,其中扫描速率在0.014mm/s～0.015mm/s处,激光抛光质量最高;而激光抛光扫描间距的减小,或者脉冲频率的增加,都将导致被加工表面粗糙度增大;当脉冲频率取8Hz时,抛光效果较好,表面粗糙度值Ra≈20nm.

Investigation on laser polishing of GaN film using deep ultraviolet laser

To study laser polishing performance of the 157nm deep ultraviolet(UV) laser, micro-surface laser etching of GaN semiconductor film was performed using a small laser-spot. After investigating the influencing relationships between the process parameters and the polishing quality, ideal process parameters were obtained. The results show that the etched surface roughness Ra gradually decreases with the speed of laser scan. When the scan speed is 0.014mm/s~0.015mm/s, the polishing quality of the etched surface is the best. With the decreasing of scan shift rate perpendicular to scan direction or with the increasing of laser repetition rate, the etched surface roughness would increase. As the laser repetition rate is 8Hz, the polishing effect is preferable and the surface roughness Ra is about 20nm.