Integrated X-ray and charged particle active pixel CMOS sensor arrays using an epitaxial silicon sensitive region
Integrated CMOS Active Pixel Sensor (APS) arrays have been fabricated and tested using X-ray and electron sources. The 128 by 128 pixel arrays, designed in a standard 0.25 micron process, use a {approx}10 micron epitaxial silicon layer as a deep detection region. The epitaxial layer has a much greater thickness than the surface features used by standard CMOS APS, leading to stronger signals and potentially better signal-to-noise ratio (SNR). On the other hand, minority carriers confined within the epitaxial region may diffuse to neighboring pixels, blur images and reduce peak signal intensity. But for low-rate, sparse-event images, centroid analysis of this diffusion may be used to increase position resolution. Careful trade-offs involving pixel size and sense-node area verses capacitance must be made to optimize overall performance. The prototype sensor arrays, therefore, include a range of different pixel designs, including different APS circuits and a range of different epitaxial layer contact structures. The fabricated arrays were tested with 1.5 GeV electrons and Fe-55 X-ray sources, yielding a measured noise of 13 electrons RMS and an SNR for single Fe-55 X-rays of greater than 38.
- Research Organization:
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
- Sponsoring Organization:
- USDOE Director. Office of Science. Office of High Energy and Nuclear Physics. Division of Nuclear Physics (US)
- DOE Contract Number:
- AC03-76SF00098
- OSTI ID:
- 834920
- Report Number(s):
- LBNL-51417; R&D Project: NRNC; TRN: US0407371
- Resource Relation:
- Conference: 2002 SPIE Conference on Visualization and Data Analysis, San Jose, CA (US), 07/08/2002--07/09/2002; Other Information: PBD: 1 Jul 2002
- Country of Publication:
- United States
- Language:
- English
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