高侧壁垂直度超浅铌酸锂光栅耦合器的加工工艺及耦合效率  

Processing Technology and Coupling Efficiency of High Sidewall Verticality and Ultra-Shallow Lithium Niobate Grating Coupler

作　　者：瞿敏妮 刘思琦 刘民[1] 李进喜 陈舒静 付学成[1] 程秀兰 Qu Minni;Liu Siqi;Liu Min;Li Jinxi;Chen Shujing;Fu Xuecheng;Cheng Xiulan(Center for Advanced Electronic Materials and Devices,School of Electronic Information and Electrical Engineering,Shanghai Jiao Tong University,Shanghai 200240,China;State Key Laboratory of Precision Spectroscopy,East China Normal University,Shanghai 200241,China)

机构地区：[1]上海交通大学电子信息与电气工程学院先进电子材料与器件平台,上海200240 [2]华东师范大学精密光谱科学与技术国家重点实验室,上海200241

出　　处：《微纳电子技术》2024年第1期131-136,共6页Micronanoelectronic Technology

基　　金：国家自然科学基金(62105199)。

摘　　要：利用聚焦离子束(FIB)在铌酸锂(LN)表面形成100 nm及以下深度的超浅光栅耦合器结构。为了提高刻蚀侧壁垂直度、避免开口展宽效应对光栅形貌的影响,在LN表面覆盖非晶硅(α-Si)作为掩膜层,实际刻蚀深度为α-Si层厚度和LN表面目标刻蚀深度之和,且刻蚀过程中产生的开口效应仅存在于α-Si层。通过氢氧化钾(KOH)溶液选择性地去除α-Si层,留下的LN表面结构侧壁陡直且无开口展宽效应。制备了刻蚀深度108 nm的超浅光栅耦合器,在924 nm波长处,其耦合效率为23.3%。制备了刻蚀深度70 nm的超浅光栅耦合器,在935 nm波长处,其耦合效率为14.4%。该研究为LN光栅耦合器的发展与应用提供了有益指导。An ultra-shallow grating coupler structure with a depth of 100 nm or below was fabricated on the surface of lithium niobate(LN)by focused ion beam(FIB).To improve the verticality of the etched side wall and avoid the influence of the opening widening effect on the grating morphology,amorphous silicon(α-Si)was deposited on the LN surface as a mask layer.And the actual etching depth is the sum of the thickness ofα-Si layer and the target etching depth on the LN surface,thus the opening effect generated during the etching process only exists in theα-Si layer.By selectively removing theα-Si layer through potassium hydroxide(KOH)solution,the remaining LN surface structure has steep sidewalls with no opening widening effect.An ultra-shallow grating coupler with an etching depth of 108 nm was prepared,and its coupling efficiency is 23.3%at 924 nm wavelength.An ultra-shallow grating coupler with an etching depth of 70 nm was prepared,and its coupling efficiency was 14.4%at 935 nm wavelength.The study provides useful guidance for the development and application of LN grating couplers.

关 键 词：超浅光栅耦合器 高侧壁垂直度 聚焦离子束(FIB) 铌酸锂(LN) 非晶硅(α-Si) 

分 类 号：TN305[电子电信—物理电子学]