Novel Ultrafast Backscattered Electron Detector With Field-Effect Transistor Enhanced In Situ Signal Amplification

• Published in: IEEE transactions on electron devices 2023-03, Vol.70 (3), p.1-6
• Main Authors: Chen, Zhu, Hu, Lilei, Zhang, Li, Shen, Jingxuan, Chen, Chang
• Format: Article
• Language: English
• Subjects: Absorption; Amplification; Anodes; Backscattered electron detectors (BSDs); backscattered electrons (BSEs); Backscattering; Biological properties; Biomedical materials; Cathodes; Detectors; Electric potential; Field effect transistors; field-effect transistor (FET); High energy electrons; High gain; high sensitivity; nonlinear doping; nonuniform gating oxide; Photonics; Semiconductor devices; Sensors; Transistors; ultrafast response
• ISSN: 0018-9383; 1557-9646
• DOI: 10.1109/TED.2023.3236907

For electron microscopy, ultrafast detectors with high sensitivity are intrinsically demanded, especially for biomedical applications, where probing electrons can damage biological samples under investigation. Addressing this, a novel ultrafast electron detector with field-effect transistor (FET) enhanced in situ signal amplification is proposed and verified in this study. Through Silvaco-based simulation, the detector demonstrates a high gain of over sevenfold of the current generated in conventional p-i-n-based detectors and an ultrafast response with a cutoff frequency of over 500 MHz. Furthermore, a proposed nonuniform gating oxide design shows an improvement in the detector output current from 61 to 87 \mu A/ \mu m. Besides, a nonlinear doping profile of the electron absorption layer is also proven effective in enhancing the in situ signal amplification effects. Particularly, a detector with a thick electron absorption layer of 50 \mu m exhibits excellent performances with an output current over 16 \mu A/ \mu m and a cutoff frequency of approximately 200 MHz, making it possible to detect high-energy electrons.