Low energy electron detector
Mar 29, 2023
Scanning electron microscopes (SEM) are indispensable for research and development as well as for failure analysis in manufacturing. Silicon electron detectors, which record the electrons backscattered from the sample, are an important component of these systems. For a particularly surface-sensitive investigation, low-energy electron beams are used, for the detection of which only limited sensitive detectors have been available up to now. The CiS Research Institute is involved in the SiekeV project to improve such detectors.
The focus is to increase the quantum efficiency of silicon diodes with respect to the irradiation of low-energy electrons. In this project a real breakthrough could be achieved (Fig. 1). This was achieved by adapted silicon processing technologies. The depth of the doped area as well as the thickness of the top layer system are essential. Both could be significantly reduced, so that low-energy electrons in the silicon can generate electron-hole pairs with high quantum efficiency.
A comparison of the detectors produced in this research project with several competing suppliers by our partner and LOI donor Carl Zeiss Microscopy AG showed that our detectors were the best - with respect to the crucial parameters of quantum efficiency at low electron energies and plasma stability.
The research and development work described was funded by the German Federal Ministry of Economic Affairs and Climate Action (BMWK) in the research project "Silicon Detector for Electrons with Energies of 1 keV" (SiekeV).
Funding code: 49MF180076