Properties of bilayer contacts to porous silicon

• DOI: 10.1007/s00339-012-6851-4
• Publication Date: 2012-03-14T09:02:36Z
• Authors: D. Gallach; V. Torres-Costa; L. García-Pelayo; A. Climent-Font; R. J. Martín-Palma; M. Barreiros-das-...; C. Sporer; J. Samitier; M. Manso
• Keywords: 0103 physical sciences; 01 natural sciences

The aim of the present work is the growth by PVD techniques and ulterior characterization of electrical contacts to columnar porous silicon (PSi) as an approach to reliable PSi sensor devices. Contacts consist of a NiCr (40:60) and Au bilayer on the PSi surface deposited by magnetron sputtering. These structures show a good adhesion to the rough surface of columnar PSi. The morphology of these electrical contacts is characterized by electron microscopy and their crystalline structure by X-ray diffraction. Compositional profiles are determined by Rutherford backscattering spectroscopy and energy dispersive X-ray spectroscopy, which demonstrate that the infiltration of NiCr into the PSi is at the origin of the metallic thin film adhesion improvement. I–V characteristics and impedance spectroscopy measurements show that this configuration provides rectifying electrical contacts to PSi, for which a simple equivalent circuit based on one resistor and two capacitors can be modeled. These results further support the use of PSi electrical structures for sensing purposes.