基于PS球自组装技术的GaN纳米柱阵列ICP刻蚀工艺研究

Research on ICP Etching Process of GaN Nanopillar Array Based on PS Sphere Self-assembly Technology

选用蓝宝石衬底上生长的P型氮化镓为材料,通过自组装技术制备的PS球为掩膜,采用感应耦合等离子体(ICP)干法刻蚀的方法来制备形状规则、周期均匀的纳米结构。在制备过程中,氮化镓纳米结构的形貌受诸多因素的影响,例如胶体球掩膜自组装的形貌,ICP刻蚀所通入的气体类型、气体比例、刻蚀功率源、刻蚀时间等。系统地研究了刻蚀过程中通入的气体类型、气体比例和刻蚀功率源、刻蚀时间对氮化镓纳米结构形貌的影响,并进行调整优化。利用扫描电子显微镜(SEM)对氮化镓进行的形貌分析表明:(1)随着刻蚀功率源和刻蚀时间的增大,掩膜层PS球的尺寸会随之减小使得刻蚀得到的纳米结构直径减小;(2)氮化镓纳米结构的形貌、刻蚀速率受到刻蚀通入的气体类型和比例影响,在Ar和CF_(4)或SF_(6)的组合气体作用下刻蚀速率相对非常缓慢,最高为15 nm/min,而Cl_(2)和BCl_(3)的组合气体作用速率可达到150 nm/min。

P-type gallium nitride grown on sapphire substrate is selected as the material,and PS spheres prepared by self-assembly technology are used as masks,inductively coupled plasma(ICP)dry etching method is used to prepare nanostructures with regular shape and uniform period.During the preparation process,the morphology of gallium nitride nanostructures is affected by many factors,such as the morphology of colloidal spherical mask self-assembly,the type of gas injected by ICP etching,the proportion of gas,the etching power source,and the etching time.The effects of gas type,gas proportion,etching power source and etching time on the morphology of gallium nitride nanostructures are studied systematically and optimized.The morphologies of gallium nitride are analyzed by scanning electron microscopy(SEM).The results showed that:(1)With the increase of etching power source and etching time,the size of PS sphere of the mask layer will decrease and the diameter of the nanostructures obtained by etching will decrease;(2)the morphology and etching rate of gallium nitride nanostructures are affected by the type and proportion of gases that are etchable.Under the action of Ar and CF_(4) or SF_(6) combined gases,the etching rate is relatively slow at 15 nm/min.The combined gas action rate of Cl_(2) and BCl_(3) can reach 150 nm/min.