Micro-LED蓝宝石衬底AlN上GaN激光剥离研究

为了比较分析纳秒激光和皮秒激光剥离微型发光二极管(micro-LED)时AlN上GaN的热传导效果, 采用了改进的实时紫外光吸收和热传导的激光剥离理论模型进行计算分析的方法, 取得了在不同的激光波长、激光脉冲宽度、激光能量密度下的紫外波段光辐照时和停止辐照后GaN材料热场分布等数据, 并获得了适合micro-LED器件剥离的所用纳秒激光和皮秒激光的阈值条件。结果表明, 激光脉宽、激光波长、激光能量密度是实现激光剥离工艺的关键因素; 较适合的激光波长为209 nm~365 nm的紫外波段; 皮秒激光的剥离效果优于纳米激光, 且激光的脉冲宽度越短, 激光的波长越短, 剥离所需激光脉冲阈值能量也越低, 则对LED芯片区域的热影响也越小。该研究可为开发新型激光剥离设备和相关工艺应用提供重要参考。

Micro-LED laser lift-off research of GaN on AlN of sapphire substrate

In order to compare laser lift-off thermal conductive effects by nanosecond laser and picosecond laser in GaN on AlN of micro light-emitting diode(micro-LED), an improved theoretical model of laser lift-off process for real-time ultraviolet light absorption and heat conduction was established. This model was used to calculate and analysis the thermal field distribution of GaN materials irradiated by various ultraviolet, laser pulses with different laser wavelength, laser pulse width, laser energy density. And the threshold conditions suitable for micro-LED devices of laser lift-off process by nanosecond laser and picosecond laser were obtained. The results show that laser pulse width, laser wavelength, and laser energy density are the key factors of laser lift-off process. The suitable laser wavelength includes 209 nm~365 nm ultraviolet band, and the laser lift-off effect of picosecond laser is better than that of nanosecond laser. Moreover, the shorter the pulse width and the shorter the wavelength of laser, the lower the threshold energy of laser pulse is needed for lift-off, and the smaller the thermal impact on the LED chip area. This research provides an important reference for the development of new laser lift-off equipment and related process applications.