Ultrafast Si-based MSM mesa photodetectors with optical waveguide connection

We have fabricated ultrafast Si metal-semiconductor-metal photodetectors an d connected them to optical waveguides. The photodetectors are fabricated i n a vertical structure consisting of a top metallization (M1), epitaxial si licon, epitaxial metallic CoSi2 (M2) and a Si substrate. In the visible reg ion, photons create electron-hole pairs in the epitaxial Si. At infrared wa velength the energy of the photons is not sufficient to create electron-hol e pairs in the Si. In this case, the Schottky contacts of both metallizatio ns provide electron and holes from internal photoemission. The best detecto rs show a pulse width of 3.2 ps full-width at half-maximum at 1.25 mum wave length and room temperature. We present data for the coupling of the detect ors to a monomode glass fiber and to polymer-based waveguides on the Si chi p. (C) 2001 Elsevier Science Ltd. Al rights reserved.