基于多层抗蚀剂的GaAs基微纳光栅深刻蚀工艺  

Deep Etching Process of GaAs-Based Micro-Nano Grating Based on Multilayer Resist

作　　者：杨晶晶 范杰 马晓辉 邹永刚 王琦琦 Yang Jingjing;Fan Jie;Ma Xiaohui;Zou Yonggang;Wang Qiqi(State Key Laboratory of High Power Semiconductor Laser,Changchun University of Science and Technology,Changchun,Jilin 130022,China)

机构地区：[1]长春理工大学高功率半导体激光国家重点实验室,吉林长春130022

出　　处：《中国激光》2022年第3期163-170,共8页Chinese Journal of Lasers

基　　金：吉林省科技发展计划项目(20190302052GX)。

摘　　要：采用电子束光刻技术制备出了深刻蚀的GaAs基微纳光栅。针对电子束曝光过程中存在的由邻近效应引起的光栅结构图形失真和变形的问题,本课题组采用厚度较薄的PMMA A4抗蚀剂和SiO_(2)薄膜形成多层抗蚀剂来减小邻近效应,同时将SiO_(2)薄膜作为硬掩模,实现了高深宽比的光栅结构。此外,针对电感耦合等离子体刻蚀过程中光栅结构出现长草的现象,通过增强电感耦合等离子体的物理刻蚀机制,有效消除了结构底部的草状结构。扫描电镜测试结果显示:将100 nm厚SiO_(2)作为硬掩模,可以实现周期为1.00μm、占空比为0.45、刻蚀深度为1.02μm的光栅结构,该光栅结构具有陡直的侧壁形貌以及良好的周期性和均匀性。在该工艺条件下,电感耦合等离子体刻蚀工艺对SiO_(2)掩模的刻蚀选择比可达26.9∶1。最后,将该结构应用于分布式布拉格反射锥形半导体激光器中,获得了线宽为40 pm的激光输出。这表明,采用电子束光刻技术制备的光栅结构对半导体激光器具有很好的选模特性。Objective Due toits high-resolution and precision pattern generation technology,electron-beam lithography has become a new generation of micro-nano structure processing technology;however,the proximity effect will cause deformation and distortion of the mask pattern.The common methods to solve the proximity effect include shape correction,dose modulation,and global horizontal sounding technique.Now,the above methods for solving the proximity effect are mostly used in studies on silicon substrates;however,relatively few studies on GaAs substrates with high atomic numbers have been published.Compared with silicon-based gratings,the use of electron-beam lithography to fabricate micro-nano gratings on GaAs substrates with larger atomic numbers is more susceptible to proximity effects.Deep etching of the grating,in particular,necessarily involves a thicker masking resist,which increases the proximity effect of the electron beam and makes good mask patterns difficult to obtain.Methods The electron-beam lithography technology was used to prepare deeply etched GaAs-based micro-nano gratings based on a multilayer resist process in this paper.Plasma enhanced chemical vapor deposition was used to construct a 100 nm thick SiO_(2)layer on the surface of the epitaxial wafer,and then a 400 nm thick PMMA A4 resist layer was spin-coated on top of the SiO_(2).Then,PMMA A4 resist and SiO_(2)film formed a multilayer resist for electron-beam lithography.After that,a grating structure was obtained by combining electron-beam lithography,reactive ion etching(RIE)etching,and inductively coupled plasma(ICP)etching.Then,the morphology of the surface and cross section of the grating structure was analyzed using a scanning electron microscope.The reasons for the formation of grass in the grating groove during the ICP etching process were investigated to understand the grass phenomenon.The effect of ratio frequency(RF)bias power on grass,grating,and SiO_(2)film was investigated further.In addition,the grating structure was used as a distribut

关 键 词：光栅 电子束光刻 邻近效应 干法刻蚀 长草现象 

分 类 号：TN305.7[电子电信—物理电子学]