We demonstrate a method for engineering substrates for surface enhanced Raman spectroscopy (SERS) by Ag− ion implantation in Si. The implantation dose and beam current density are chosen such that the Ag concentration in Si exceeds the solid solubility limit, causes aggregation of Ag and nucleates Ag nano particles. The embedded nano particles are then partially exposed by a wet etch process. Our measurements show that the so fabricated nano-composite substrates are very effective as stable and reproducible SERS substrates. Copyright © 2013 John Wiley & Sons, Ltd.