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采用157 nm波长准分子激光,对LED-GaN半导体薄膜进行了刻蚀试验研究。探讨了GaN基半导体材料的基本刻蚀特性和刻蚀机理。结果表明,157 nm激光在能量密度高于2.5 J/cm2时,刻蚀速率可达50 nm/pulse以上。以低于16 Hz脉冲频率和高于0.25 mm/min的扫描速度进行激光直写刻蚀时,可以获得Ra30 nm以下的表面粗糙度。采用扫描刻蚀方法,可以加工出75°左右的刻蚀壁面。实验也证明157 nm激光在三维微结构加工方面具有较大的潜力。单光子吸收电离引起的光化学反应是157 nm激光刻蚀GaN基材料的主要机理。
Using 157 nm wavelength excimer laser, the LED-GaN semiconductor thin films were etched. The basic etching characteristics and etching mechanism of GaN-based semiconductor materials are discussed. The results show that the etching rate of 157 nm laser can reach more than 50 nm / pulse when the energy density is higher than 2.5 J / cm2. Laser direct writing etching at pulse frequencies below 16 Hz and scanning speeds above 0.25 mm / min results in surface roughness below Ra30 nm. The use of scanning and etching method, you can work out about 75 ° etching wall. Experiments also prove that 157 nm laser has great potential in three-dimensional microstructure processing. The photochemical reaction induced by single-photon absorption ionization is the main mechanism of 157 nm laser-etching of GaN-based materials.