## 4 Conclusions  
In order to analyze the particles remaining in the epitaxial growth chamber after the process, an ELII was applied. As a result of measuring the concentrations of residual particles in the epitaxial growth chamber during the N\({}_{2}\) purge using ELII, it was possible to obtain particle size distribution and see the distribution trend for both the number concentration and mass concentration. Using the advantage of real-time measurement, it was confirmed that N\({}_{2}\) purge operation was well performed after the process. The particle shape and composition were confirmed by SEM analysis of particles collected at each stage of the cascade impactor. Since various substrates could be mounted on each stage of the cascade impactor of the ELII, a substrate with a low surface roughness is recommended when detecting particle shape images. To accurately identify the occurrence and inflow paths of each component, after collecting a large number of particles using a sufficient collection time, various in-depth additional analyses are required.  
We performed a cornerstone study of the application of ELII for particle analysis for process equipment in the semiconductor industry and other industries. The first application point found in this study is the real-time monitoring of chamber purge performance after the process for preventive maintenance using the advantage of real-time measurement. After confirming that the number of particles has fallen to a certain level before proceeding to the next process, it is possible to prevent the possible influence of residual particles on the process. This novel measurement mechanism provides critical information allowing us to reduce impurities and increase the rate of crystal growth. In addition, as this is a process that does not use explosive gas and which is conducted at normal pressure and room temperature, the concentration of the particles generated during the process can be monitored in real time. In addition, the ELII method has a clear advantage of real-time particle concentration measurement and simultaneous collection. Thus, it can be more actively used for particle measurement and analysis in the semiconductor industry, which is plagued by many micro/nanoparticle issues.  
Conceptualization, S.L., D.K.; Methodology, S.L., D.K., S.K., H.L.; Formal analysis, S.L., E.K., P.L.; Investigation, S.L., D.K., E.K., D.-B.K.; Resources, S.K., H.L.; Data curation, S.L., Y.C.; Writing--original draft preparation, S.L.; Writing--review and editing, S.L., D.K., Y.C., T.K., D.-B.K.; Visualization, S.L., P.L., Y.C.; Supervision, T.K.; Project administration, S.L., T.K., S.K., H.L.; Funding acquisition, D.K., T.K., H.L. All authors have read and agreed to the published version of the manuscript.  
This research was funded by Korean government (MSIT), grant number 2020 MSHIA1077095, MOTIE (Ministry of Trade, Industry, and Energy), grant number P0008746, SK Siltron Co. Ltd. of funder, grant number 201807059.  
Not applicable.  
This research was supported by Korea Initiative for fostering University of Research and Innovation Program of the National Research Foundation (NRF) funded by the Korean government (MSIT) (No.2020M3H1A1077095). This research was also supported by the MOTIE (Ministry of Trade, Industry, and Energy) of Korea under the Fostering Global Talents for Innovative Growth Program (P0008746) supervised by the Korea Institute for Advancement of Technology (KIAT). We also give our deepest appreciation to SK Siltron Co., Ltd. for their support and cooperation.  
The authors have no conflict of interest relevant to this study to disclose.