{"title":"低真空扫描电镜中二次电子超变压探测器的表征。","authors":"Yuanzhao Yao, Ryosuke Sonoda, Yasunari Sohda, Takashi Sekiguchi","doi":"10.1093/jmicro/dfaf037","DOIUrl":null,"url":null,"abstract":"<p><p>Scanning electron microscope (SEM) observation in low vacuum can overcome the issue of charge-up at the specimen surface, allowing for the observation of insulating samples without sample pretreatment. The ultra-variable-pressure detector (UVD) was developed as a secondary electron (SE) detector for the low vacuum observation in SEM. It works by collecting the light signal released from the collision between secondary electrons and gas molecules. In this study, we propose a simple method using a stainless steel (SUS) sphere to characterize the feature of UVD signal in low vacuum SEM, and compare it with the traditional Everhart-Thornley (E-T) detector in normal SEM. The UVD signal showed characteristic features, namely a two-round-peak feature in the profile, which is different from that of E-T detector. By experiment and simulation, we revealed that at higher vacuum levels (as a few Pa), SEs provide the primary contribution to the UVD signal, exhibiting a profile similar to that of the E-T signal. As the vacuum deteriorates, as 30 Pa, the main contribution to the UVD signal shifts from SEs to low energy backscattered electrons (BSE). Our finding indicates that by tuning the chamber pressure, we can vary the UVD image between SE and low energy BSE features.</p>","PeriodicalId":74193,"journal":{"name":"Microscopy (Oxford, England)","volume":" ","pages":""},"PeriodicalIF":1.9000,"publicationDate":"2025-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Characterization of ultra-variable-pressure detector for secondary electrons in low vacuum SEM.\",\"authors\":\"Yuanzhao Yao, Ryosuke Sonoda, Yasunari Sohda, Takashi Sekiguchi\",\"doi\":\"10.1093/jmicro/dfaf037\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p><p>Scanning electron microscope (SEM) observation in low vacuum can overcome the issue of charge-up at the specimen surface, allowing for the observation of insulating samples without sample pretreatment. The ultra-variable-pressure detector (UVD) was developed as a secondary electron (SE) detector for the low vacuum observation in SEM. It works by collecting the light signal released from the collision between secondary electrons and gas molecules. In this study, we propose a simple method using a stainless steel (SUS) sphere to characterize the feature of UVD signal in low vacuum SEM, and compare it with the traditional Everhart-Thornley (E-T) detector in normal SEM. The UVD signal showed characteristic features, namely a two-round-peak feature in the profile, which is different from that of E-T detector. By experiment and simulation, we revealed that at higher vacuum levels (as a few Pa), SEs provide the primary contribution to the UVD signal, exhibiting a profile similar to that of the E-T signal. As the vacuum deteriorates, as 30 Pa, the main contribution to the UVD signal shifts from SEs to low energy backscattered electrons (BSE). Our finding indicates that by tuning the chamber pressure, we can vary the UVD image between SE and low energy BSE features.</p>\",\"PeriodicalId\":74193,\"journal\":{\"name\":\"Microscopy (Oxford, England)\",\"volume\":\" \",\"pages\":\"\"},\"PeriodicalIF\":1.9000,\"publicationDate\":\"2025-09-04\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Microscopy (Oxford, England)\",\"FirstCategoryId\":\"1085\",\"ListUrlMain\":\"https://doi.org/10.1093/jmicro/dfaf037\",\"RegionNum\":0,\"RegionCategory\":null,\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"\",\"JCRName\":\"\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Microscopy (Oxford, England)","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.1093/jmicro/dfaf037","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
Characterization of ultra-variable-pressure detector for secondary electrons in low vacuum SEM.
Scanning electron microscope (SEM) observation in low vacuum can overcome the issue of charge-up at the specimen surface, allowing for the observation of insulating samples without sample pretreatment. The ultra-variable-pressure detector (UVD) was developed as a secondary electron (SE) detector for the low vacuum observation in SEM. It works by collecting the light signal released from the collision between secondary electrons and gas molecules. In this study, we propose a simple method using a stainless steel (SUS) sphere to characterize the feature of UVD signal in low vacuum SEM, and compare it with the traditional Everhart-Thornley (E-T) detector in normal SEM. The UVD signal showed characteristic features, namely a two-round-peak feature in the profile, which is different from that of E-T detector. By experiment and simulation, we revealed that at higher vacuum levels (as a few Pa), SEs provide the primary contribution to the UVD signal, exhibiting a profile similar to that of the E-T signal. As the vacuum deteriorates, as 30 Pa, the main contribution to the UVD signal shifts from SEs to low energy backscattered electrons (BSE). Our finding indicates that by tuning the chamber pressure, we can vary the UVD image between SE and low energy BSE features.