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Advances in OptoElectronics
Volume 2011 (2011), Article ID 965967, 10 pages
http://dx.doi.org/10.1155/2011/965967
Research Article

Microcavity Silicon Photodetectors at 1.55 μm

1Department of Naples, Institute for Microelectronics and Microsystems, National Council of Research, Via P. Castellino 111, 80131 Naples, Italy
2Department of Mathematics, Seconda Università degli Studi di Napoli, Via Vivaldi 43, 81100 Caserta, Italy

Received 25 June 2010; Revised 16 September 2010; Accepted 22 October 2010

Academic Editor: Snjezana Tomljenovic-Hanic

Copyright © 2011 M. Casalino et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The design, the realization, and the characterization of silicon resonant cavity enhanced (RCE) photodetectors, working at 1.55 μm, are reported. The photodetectors are constituted by a Fabry-Perot microcavity incorporating a Schottky diode. The working principle is based on the internal photoemission effect. We investigated two types of structures: top and back-illuminated. Concerning the top-illuminated photodetectors, a theoretical and numerical analysis has been provided and the device quantum efficiency has been calculated. Moreover, a comparison among three different photodetectors, having as Schottky metal: gold, silver, or copper, was proposed. Concerning the back-illuminated devices, two kinds of Cu/p-Si RCE photodetectors, having various bottom-mirror reflectivities, were realized and characterized. Device performances in terms of responsivity, free spectral range, and finesse were theoretically and experimentally calculated in order to prove an enhancement in efficiency due to the cavity effect. The back-illuminated device fabrication process is completely compatible with the standard silicon technology.