15 June 2006 Development of fully depleted and back-illuminated charge coupled devices for soft x-ray imager onboard the NeXT satellite
Author Affiliations +
The NeXT (New X-ray Telescope) satellite to be launched around 2010, has a large effective area in the 0.1-80 keV band with the use of the multilayer super mirror (HXT). As one of the focal plane detectors for NeXT, we have been developing the Soft X-ray Imager (SXI). SXI consists of charge coupled devices (CCDs). In order to increase the quantum efficiency (Q.E.) as high as possible, i.e., to detect X-rays collected by HXT as many as possible, we developed a "fully-depleted and back-illuminated CCD" in the attempt to improve the Q.E. of soft X-rays by the back-illuminated structure and that of hard X-rays by thickening of a depletion layer. Thanks to a high-resistivity (over 10kΩ•cm) n-type Si, we have successfully developed Pch CCDs with very thick depletion layer of over 300 micron, which is 4 times thicker than that of established X-ray MOS CCDs (for example XIS, EPIC-MOS and ACIS-I). Furthermore, we have already confirmed we can thin a wafer down to 150 micron independent of its resistivity from the experience of the development of the back supportless CCD. Based on these successful results, we fabricated a test device of "fully depleted and back-illuminated CCD" with the high resistivity (10kOhm cm) N-type Si thinned down to 200 micron. The pixel number and size are 512 x 512 and 24 x 24 μm, respectively. For optical blocking, we coated the surface with Al. We evaluated this test device and confirmed the thickness of depletion layer reaches 200 micron as we expected. In this paper, we present progress in development of these devices for SXI.
© (2006) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Shin-ichiro Takagi, Shin-ichiro Takagi, Takeshi Go Tsuru, Takeshi Go Tsuru, Tatsuya Inui, Tatsuya Inui, Midori Ozawa, Midori Ozawa, Hironori Matsumoto, Hironori Matsumoto, Katsuji Koyama, Katsuji Koyama, Hiroshi Tsunemi, Hiroshi Tsunemi, Emi Miyata, Emi Miyata, Hideki Ozawa, Hideki Ozawa, Daisuke Matsuura, Daisuke Matsuura, Masakuni Tohiguchi, Masakuni Tohiguchi, Satoshi Miyazaki, Satoshi Miyazaki, Yukiko Kamata, Yukiko Kamata, Kazuhisa Miyaguchi, Kazuhisa Miyaguchi, Masaharu Muramatsu, Masaharu Muramatsu, Hisanori Suzuki, Hisanori Suzuki, "Development of fully depleted and back-illuminated charge coupled devices for soft x-ray imager onboard the NeXT satellite", Proc. SPIE 6266, Space Telescopes and Instrumentation II: Ultraviolet to Gamma Ray, 62663V (15 June 2006); doi: 10.1117/12.672657; https://doi.org/10.1117/12.672657


Back to Top