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Proceedings Paper

Exploration of the potential performance of polycrystalline silicon-based active matrix flat-panel imagers incorporating active pixel sensor architectures
Author(s): Larry E. Antonuk; Youcef El-Mohri; Qihua Zhao; Martin Koniczek; John McDonald; Mike Yeakey; Yi Wang; Mahdokht Behravan; Robert A. Street; JengPing Lu
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Paper Abstract

Conventional active matrix flat-panel imagers (AMFPIs), employing amorphous silicon (a-Si:H) semiconductors, are based on a relatively simple pixel architecture, commonly taking the form of a single, thin-film transistor (TFT) coupled to a pixel storage capacitor. Although this semiconductor-architecture combination has led to the successful creation of x-ray imagers for many applications, a variety of significant performance limitations related to DQE, frame rate and charge trapping have also become apparent. While prospects for designing solutions to these restrictions based on a-Si:H TFTs are uncertain, progress in the development of high-quality polycrystalline silicon (poly-Si) TFTs is opening up new possibilities for large area x-ray imager design. Recently, initial prototype imagers have been developed using poly-Si TFTs in the form of 1-stage and 2-stage pixel amplifiers-ircuit architectures that can generally be referred to as active pixel sensors (APS). The insight gained from empirical evaluations of such prototypes, coupled with theoretical studies, can inspire increasingly sophisticated APS architectures that overcome the limitations, while preserving the advantages, of conventional AMFPIs. In this paper, cascaded systems analysis and circuit simulation are used to explore potential performance improvements enabled by APS architectures based on poly-Si TFTs. These studies suggest that it is possible to achieve significant improvements in DQE at low exposures or very small pixel sizes, higher maximum frame rates, and reduced charge trapping effects through implementation of such architectures.

Paper Details

Date Published: 25 March 2008
PDF: 13 pages
Proc. SPIE 6913, Medical Imaging 2008: Physics of Medical Imaging, 69130I (25 March 2008); doi: 10.1117/12.771406
Show Author Affiliations
Larry E. Antonuk, Univ. of Michigan (United States)
Youcef El-Mohri, Univ. of Michigan (United States)
Qihua Zhao, Univ. of Michigan (United States)
Martin Koniczek, Univ. of Michigan (United States)
John McDonald, Univ. of Michigan (United States)
Mike Yeakey, Univ. of Michigan (United States)
Yi Wang, Univ. of Michigan (United States)
Mahdokht Behravan, Univ. of Michigan (United States)
Robert A. Street, Palo Alto Research Ctr. (United States)
JengPing Lu, Palo Alto Research Ctr. (United States)


Published in SPIE Proceedings Vol. 6913:
Medical Imaging 2008: Physics of Medical Imaging
Jiang Hsieh; Ehsan Samei, Editor(s)

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