Oxidation smoothening of silicon machined micro- and nano-scale structures

We have developed a process to machine bulk silicon in two- and three-dimensions shapes and structures. Here we briefly introduce this process and give examples of the types of surface profiles and three-dimensional geometries which can be fabricated. One of the limitations, as with all forms of silicon machining is the final surface roughness, as this introduces losses, for example in light propagation through photonic devices. Here we describe various contributing factors to the surface roughness and options to reducing it. Under optimized conditions roughness values of less than 1 nm can be achieved. (C) 2014 Elsevier B.V. All rights reserved.