Critically coupled silicon Fabry-Perot photodetectors based on the internal photoemission effect at 1550 nm

• Published in: Optics express Vol. 20; no. 11; p. 12599
• Main Authors: Casalino, Maurizio, Coppola, Giuseppe, Iodice, Mario, Rendina, Ivo, Sirleto, Luigi
• Format: Journal Article
• Language: English
• Published: United States 21.05.2012
• Subjects: Equipment Design; Equipment Failure Analysis; Interferometry - instrumentation; Miniaturization; Photometry - instrumentation; Semiconductors; Silicon - chemistry
• ISSN: 1094-4087; 1094-4087
• DOI: 10.1364/OE.20.012599

In this paper, design, fabrication and characterization of an all-silicon photodetector (PD) at 1550 nm, have been reported. Our device is a surface-illuminated PD constituted by a Fabry-Perot microcavity incorporating a Cu/p-Si Schottky diode. Its absorption mechanism, based on the internal photoemission effect (IPE), has been enhanced by critical coupling condition. Our experimental findings prove a peak responsivity of 0.063 mA/W, which is the highest value obtained in a surface-illuminated IPE-based Si PD around 1550 nm. Finally, device capacitance measurements have been carried out demonstrating a capacitance < 5 pF which has the potential for GHz operation subject to a reduction of the series resistance of the ohmic contact.