利用干燥空气改善熔融KOH对单晶碳化硅的腐蚀  

Optimization of KOH Etching for Single Crystal SiC by Dry Air

作　　者：孙帅 宋华平 杨军伟 王文军 屈红霞[2] 简基康 SUN Shuai;SONG Huaping;YANG Junwei;WANG Wenjun;QU Hongxia;JIAN Jikang(School of Physics and Optoelectronic Engineering,Guangdong University of Technology,Guangzhou 510006,China;Songshan Lake Materials Laboratory,Dongguan 523808,China;Research and Development Center for Functional Crystals,Beijing National Laboratory for Condensed Matter Physics,Institute of Physics,Chinese Academy of Sciences,Beijing 100190,China)

机构地区：[1]广东工业大学物理与光电工程学院,广州510006 [2]松山湖材料实验室,东莞523808 [3]中国科学院物理研究所功能晶体研究与应用中心,北京100190

出　　处：《人工晶体学报》2023年第5期753-758,共6页Journal of Synthetic Crystals

基　　金：广东省自然科学基金-面上项目(2022A1515012628)。

摘　　要：本文提出了一种改进的氢氧化钾(KOH)腐蚀方法,该方法利用鼓泡器将干燥空气直接通入熔融KOH中,以达到快速排出熔融KOH中水分和增强溶解氧的目的。本研究通过提升部分潮解的KOH对低掺杂n型外延片的腐蚀效果和纯KOH对高掺杂n型衬底的腐蚀效果,验证了该方法的有效性。实验结果表明:在腐蚀前的恒温时间段内,向腐蚀剂通入干燥空气,可加快腐蚀剂中水分的蒸发速度,减轻水分对腐蚀反应的抑制作用,使得部分潮解的KOH用于腐蚀外延片的效果优于未潮解的新鲜KOH;在腐蚀时向腐蚀剂通入干燥空气,可增加腐蚀剂中的溶解氧,促进腐蚀时发生的氧化还原反应,使得KOH腐蚀SiC衬底的效果近似于用KOH+Na_(2)O_(2)共熔体腐蚀得到的效果。本研究有效改良了传统KOH腐蚀方法,对于稳定KOH腐蚀条件,提高SiC位错腐蚀效果具有很好的实际应用价值。KOH etching is a convenient method with high efficiency for characterizing dislocations in SiC.However,the etching process is often affected due to the hydrolysis of KOH.To ensure stability and reproducibility of the etching process,frequent replacement of KOH is necessary,which leads to a large consumption of the etching materials.In this study,an improved method for KOH etching technique was proposed by directly injecting dry air into the molten KOH through a bubbler,in order to quickly remove moisture from the molten KOH and enhance dissolved oxygen.The effectiveness of the method is verified by etching lightly doped n-type epitaxial wafers and heavily doped n-type substrates.The experimental results show that introducing dry air into the molten KOH during the constant temperature stage before etching the SiC epitaxial wafer accelerate the evaporation of moisture in partially deliquescent KOH and achieve a faster etching rate of dislocations than fresh KOH.In the substrate etching experiment,an increase in the concentration of dissolved oxygen in the etchant is obtained by introducing dry air into the molten KOH,which promotes the etching effect through promoting the chemical reaction on SiC surface.As a result,an etching rate of dislocations similar to that of the mixed etchant of Na_(2)O_(2) and KOH is achieved.This research provides a helpful method to improve the etching effect of SiC dislocations,which would have practical value in SiC production.

关 键 词：碳化硅 腐蚀 位错 缺陷表征 鼓泡器 腐蚀速率 

分 类 号：TM23[一般工业技术—材料科学与工程]