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Proceedings Paper

Flexible amorphous silicon PIN diode x-ray detectors
Author(s): Michael Marrs; Edward Bawolek; Joseph T. Smith; Gregory B. Raupp; David Morton
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Paper Abstract

A low temperature amorphous silicon (a-Si) thin film transistor (TFT) and amorphous silicon PIN photodiode technology for flexible passive pixel detector arrays has been developed using active matrix display technology. The flexible detector arrays can be conformed to non-planar surfaces with the potential to detect x-rays or other radiation with an appropriate conversion layer. The thin, lightweight, and robust backplanes may enable the use of highly portable x-ray detectors for use in the battlefield or in remote locations. We have fabricated detector arrays up to 200 millimeters along the diagonal on a Gen II (370 mm x 470 mm rectangular substrate) using plasma enhanced chemical vapor deposition (PECVD) a-Si as the active layer and PECVD silicon nitride (SiN) as the gate dielectric and passivation. The a-Si based TFTs exhibited an effective saturation mobility of 0.7 cm2/V-s, which is adequate for most sensing applications. The PIN diode material was fabricated using a low stress amorphous silicon (a-Si) PECVD process. The PIN diode dark current was 1.7 pA/mm2, the diode ideality factor was 1.36, and the diode fill factor was 0.73. We report on the critical steps in the evolution of the backplane process from qualification of the low temperature (180°C) TFT and PIN diode process on the 150 mm pilot line, the transfer of the process to flexible plastic substrates, and finally a discussion and demonstration of the scale-up to the Gen II (370 x 470 mm) panel scale pilot line.

Paper Details

Date Published: 29 May 2013
PDF: 7 pages
Proc. SPIE 8730, Flexible Electronics, 87300C (29 May 2013); doi: 10.1117/12.2015917
Show Author Affiliations
Michael Marrs, Arizona State Univ. (United States)
Edward Bawolek, Arizona State Univ. (United States)
Joseph T. Smith, Arizona State Univ. (United States)
Gregory B. Raupp, Arizona State Univ. (United States)
David Morton, U.S. Army Research Lab. (United States)

Published in SPIE Proceedings Vol. 8730:
Flexible Electronics
David R. Allee; Eric W. Forsythe, Editor(s)

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