Fabrication of a thin silicon detector with excellent thickness uniformity

• Published in: Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment Accelerators, spectrometers, detectors and associated equipment, 2016-02, Vol.810, p.27-31
• Main Authors: Valtonen, E., Eronen, T., Nenonen, S., Andersson, H., Miikkulainen, K., Eränen, S., Ronkainen, H., Mäkinen, J., Husu, H., Lassila, A., Punkkinen, R., Hirvonen, M.
• Format: Article
• Language: English
• Subjects: Accelerators; Detectors; Energetic particles; Fizeau interferometer; Segments; Silicon; Silicon detector; SOI technology; Solar energetic particles; Space telescopes; Specifications; Thickness uniformity; Variability; ΔE-E
• ISSN: 0168-9002; 1872-9576
• DOI: 10.1016/j.nima.2015.11.124

We have fabricated and tested a thin silicon detector with the specific goal of having a very good thickness uniformity. SOI technology was used in the detector fabrication. The detector was designed to be used as a ΔE detector in a silicon telescope for measuring solar energetic particles in space. The detector thickness was specified to be 20μm with an rms thickness uniformity of±0.5%. The active area consists of three separate elements, a round centre area and two surrounding annular segments. A new method was developed for measuring the thickness uniformity based on a modified Fizeau interferometer. The thickness uniformity specification was well met with the measured rms thickness variation of 43nm. The detector was electrically characterized by measuring the I–V and C–V curves and the performance was verified using a 241Am alpha source.