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Proceedings Paper

Development of silicon-germanium visible-near infrared arrays
Author(s): John W. Zeller; Caitlin Rouse; Harry Efstathiadis; Pradeep Haldar; Jay S. Lewis; Nibir K. Dhar; Priyalal Wijewarnasuriya; Yash R. Puri; Ashok K. Sood
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Paper Abstract

Photodetectors based on germanium which do not require cooling and can provide good near-infrared (NIR) detection performance offer a low-cost alternative to conventional infrared sensors based on material systems such as InGaAs, InSb, and HgCdTe. As a result of the significant difference in thermal expansion coefficients between germanium and silicon, tensile strain incorporated into Ge epitaxial layers deposited on Si utilizing specialized growth processes can extend the operational range of detection to 1600 nm and longer wavelengths. We have fabricated Ge based PIN photodetectors on 300 mm diameter Si wafers to take advantage of high throughput, large-area complementary metal-oxide semiconductor (CMOS) technology. This device fabrication process involves low temperature epitaxial deposition of Ge to form a thin p+ (boron) Ge seed/buffer layer, and subsequent higher temperature deposition of a thicker Ge intrinsic layer. This is followed by selective ion implantation of phosphorus of various concentrations to form n+ Ge regions, deposition of a passivating oxide cap, and then top copper contacts to complete the PIN detector devices. Various techniques including transmission electron microscopy (TEM) and secondary ion mass spectrometry (SIMS) have been employed to characterize the material and structural properties of the epitaxially grown layers and fabricated detector devices, and these results are presented. The I-V response of the photodetector devices with and without illumination was also measured, for which the Ge based photodetectors consistently exhibited low dark currents of around ~1 nA at -1 V bias.

Paper Details

Date Published: 26 May 2016
PDF: 9 pages
Proc. SPIE 9854, Image Sensing Technologies: Materials, Devices, Systems, and Applications III, 985408 (26 May 2016); doi: 10.1117/12.2229650
Show Author Affiliations
John W. Zeller, Magnolia Optical Technologies Inc. (United States)
Caitlin Rouse, State Univ. of New York Polytechnic Institute (United States)
Harry Efstathiadis, State Univ. of New York Polytechnic Institute (United States)
Pradeep Haldar, State Univ. of New York Polytechnic Institute (United States)
Jay S. Lewis, DARPA/MTO (United States)
Nibir K. Dhar, U.S. Army Night Vision Sensors and Electronic Division (United States)
Priyalal Wijewarnasuriya, U.S. Army Research Lab. (United States)
Yash R. Puri, Magnolia Optical Technologies Inc. (United States)
Ashok K. Sood, Magnolia Optical Technologies Inc. (United States)

Published in SPIE Proceedings Vol. 9854:
Image Sensing Technologies: Materials, Devices, Systems, and Applications III
Nibir K. Dhar; Achyut K. Dutta, Editor(s)

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