%0 Journal Article
%T Microcavity Silicon Photodetectors at 1.55£¿¦Ìm
%A M. Casalino
%A G. Coppola
%A M. Gioffr¨¨
%A M. Iodice
%A L. Moretti
%A I. Rendina
%A L. Sirleto
%J Advances in OptoElectronics
%D 2011
%I Hindawi Publishing Corporation
%R 10.1155/2011/965967
%X The design, the realization, and the characterization of silicon resonant cavity enhanced (RCE) photodetectors, working at 1.55£¿¦Ìm, 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. 1. Introduction In the last two decades, there has been growing interest in photonic devices based on Si-compatible materials [1, 2] in the field of both optical telecommunications and optical interconnects. In this context, tremendous progresses in the technological processes have allowed to realize effectively fully CMOS compatible optical components, such as low-loss waveguides, high-Q resonators, high speed modulators, couplers, and optically pumped lasers [3¨C8]. All these devices have been developed to operate in the wavelength range from the C optical band (1528¨C1561£¿nm) to the L optical band (1561¨C1620£¿nm) where the defect-free intrinsic bulk Si has minimal absorption. On the other hands, this transparency window limits the Si applications as absorbing material for infrared photodetection, so that the development of high-performance waveguide-integrated photodetectors on Si-CMOS platform has remained an imperative but unaccomplished task. In order to develop all Si photodetectors and to take advantage of the low-cost standard Si-CMOS processing technology without additional materials or process steps, a number of options have been proposed, in particular, the two-photon absorption (TPA) [9], the incorporation of optical dopants/defects with mid-bandgap energy levels into the Si lattice [10, 11], and the internal photoemission effect (IPE) [12]. The IPE has been recently used also in silicon photodetectors realized with plasmonics
%U http://www.hindawi.com/journals/aoe/2011/965967/