Electrochemical Etching Methods for Producing Porous Silicon

Porous silicon produced by electrochemical etching of silicon has become one of the most popular materials used in many scientific disciplines as a result of its outstanding and unique set of chemical and physical properties and cost-competitive fabrication processes. To understand the electrochemical mechanisms taking place in the course of the etching of silicon is a key factor to control and modify the structure of this versatile porous material. This makes it possible to produce a broad range of structures, which can range from a porous matrix to arrays of nanowires. These structures are unique and bring new opportunities for multiple research fields and applications such as biotechnology, medicine, optoelectronics, chemistry and so forth. This chapter is aimed at compiling and summarising the fundamental aspects behind the production of porous silicon structures by electrochemical and metal-assisted etching of silicon wafers. Our objective is to provide a simple but detailed overview about the fabrication process of porous silicon, with special emphasis on the different fabrication conditions and geometric and morphological features of the resulting silicon nanostructures.