In this work, Si pn junction diode-based electron beam detector with high sensitivity for low acceleration voltage and high readout speed is reported, by using steep pn junction formation technology, low dopant concentration Si substrate and multiple signal outputs. The electron quantum efficiency of fabricated detector at acceleration voltage of 1.0kV, 10kV, 20kV are 51.8%, 70.3% and 90.8%, respectively, which is suitable for low acceleration voltage scanning electron microscope. Also, by dividing the detector area into multiple regions, the pn junction capacitance is significantly reduced to 1/3 and 1/7 compared to the conventional structure, which is suitable for high signal readout speed that is limited by RC delay of pn junction.
Yasumasa Koda, Rihito Kuroda, Masaya Hara, Hiroyuki Tsunoda, Shigetoshi Sugawa, "High Sensitivity and High Readout Speed Electron Beam Detector using Steep pn Junction Si diode for Low Acceleration Voltage" in Proc. IS&T Int’l. Symp. on Electronic Imaging: Image Sensors and Imaging Systems, 2017, pp 14 - 17, https://doi.org/10.2352/ISSN.2470-1173.2017.11.IMSE-178