Processing and characterization of edgeless radiation detectors for large area detection

Juha Kalliopuska (1), Xiaopeng. Wu (2), Jan Jakubek (3), Simo Eränen (2), Tuula Virolainen (2)

(1) Advacam Oy Ltd, Espoo, Finland

(2) VTT Technical Research Centre of Finland, Espoo, Finland

(3) Institure of Experimental and Applied Physics, IEAP-CTU, Prague, Czech Republic

The edgeless or active edge silicon pixel detectors have been gaining a lot of interest due to improved silicon processing capabilities. At VTT, we have recently triggered a multi-project wafer process of edgeless silicon detectors. Totally 80 pieces of 150 mm wafers were processed to provide a given number of detector variations. Fabricated detector thicknesses were 100, 200, 300 and 500 µm. The polarities of the fabricated detectors on the given thicknesses were n-in-n, p-in-n, n-in-p and p-in-p. On the n-in-n and n-in-p wafers the pixel isolation was made either with a common p-stop grid or with a shallow p-spray doping. The wafer materials were high resistivity Float Zone and Magnetic Czochralski silicon with crystal orientation of <100>. In this paper, the electric properties on various types of detectors are presented. The results from spectroscopic measurement show a good energy resolution of the edge pixels, indicating an excellent charge collection near the edge pixels of the edgeless detector.


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