KCl溶液结晶辅助表征4H-SiC衬底中的微划痕  

Characterization of Micro-Scratches on 4H-SiC Substrates by KCl Solution Crystallization-Assisted Method

作　　者：张翅腾飞 章嵩[2] 龚若程 杨军伟 宋华平 ZHANG Chitengfei;ZHANG Song;GONG Ruocheng;YANG Junwei;SONG Huaping(Hubei Longzhong Laboratory,Xiangyang 441000,China;State Key Laboratory of Advanced Technology for Materials Synthesis and Processing,Wuhan University of Technology,Wuhan 430070,China;Songshan Lake Materials Laboratory,Dongguan 523808,China;PowerEpi Semiconductor Co.,Ltd.,Dongguan 523786,China)

机构地区：[1]湖北隆中实验室,襄阳441000 [2]武汉理工大学材料复合新技术国家重点实验室,武汉430070 [3]松山湖材料实验室,东莞523808 [4]东莞市中科汇珠半导体有限公司,东莞523786

出　　处：《人工晶体学报》2024年第10期1745-1751,共7页Journal of Synthetic Crystals

基　　金：湖北省自然科学基金(2023AFB1000);材料复合新技术国家重点实验室(武汉理工大学)开放基金(2024-KF-18);广东省自然科学基金-面上项目(2022A1515012628)。

摘　　要：4H-SiC晶圆表面的微划痕会使外延层中产生大量缺陷,但其线宽低于光学表征技术的极限,无法以无损光学检测的方法获得微划痕在晶圆上的分布规律。本研究基于经典成核理论,利用微划痕上的高指数晶面,通过溶液干燥析晶的方法,使KCl晶体优先成核于高表面能的高指数晶面。实验结果表明:当KCl溶液的浓度为0.013 mol/L时,溶液蒸发后的KCl晶体嵌于微划痕的沟壑内,使微划痕可以间接地被光学方法检测。当KCl溶液的浓度大于0.013 mol/L时,KCl晶体会结晶于没有微划痕的区域,干扰对微划痕的表征。本方法制备的KCl晶体仅吸附成核于4H-SiC表面,不与4H-SiC发生化学反应,通过RCA清洗工艺即可完全去除表面的KCl晶体,不影响晶圆的后续加工工艺。Micro-scratches on 4H-SiC wafers can transform into dislocations,stacking fault and other type of defects during homoepitaxial process,leading to reduce yield of epitaxial wafers.These micro-scratches are challenging to detect using non-destructive optical characterization methods due to their ultra-thin line width,which is beyond the resolution of current optical technology.A novel method has been developed to reveal these micro-scratches,which are typically invisible under optical microscopy,on SiC wafers after chemo-mechanical polishing(CMP)treatment.This method is based on the classical nucleation theory,and KCl crystals preferentially nucleate on high-index crystallographic facets with high surface energy during the KCl solution drying process.The experimental results show that the KCl crystals could embed in the ravines of the micro-scratches at a KCl solution concentration of 0.013 mol/L,allowing for their indirect detection by optical microscopy.When the concentration of KCl solution is greater than 0.013 mol/L,lots of KCl crystals crystallize on the areas without micro-scratches and interfere with the characterization of micro-scratches.KCl crystals formed by this method can be removed from the surface through the RCA cleaning process without impacting the subsequent wafer processing,because they are adsorbed and nucleated on the surface of 4H-SiC without undergoing any chemical reaction with SiC substrates.

关 键 词：4H-SIC 微划痕 KCl溶液 成核理论 高指数晶面 表面能 

分 类 号：O766[理学—晶体学]