Progress in Development of Monolithic Active Pixel Detector for X-ray Astronomy with SOI CMOS Technology

We have been developing an active pixel sensor for X-ray astronomy. In this paper, we report on the design and the characterization of the recently-developed device named XRPIX1-FZ. We applied the high-resistivity Si wafer (similar to 7 k Omega cm) to the sensor layer for a thick depletion layer. The chemical-mechanical polishing, which we applied to smooth the rough backside of the Si wafer, successfully reduced the dark current. We used the single-pixel readout mode and achieved the energy resolution of 260 eV in FWHM at 8 keV. Moreover, we developed the 3 x 3 pixel readout mode for the evaluation of split events and confirmed the full depletion of 250 mu m thick at the reverse-bias voltage of 30 V. (C) 2012 Published by Elsevier B.V. Selection and/or peer review under responsibility of the organizing committee for TIPP 11.