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

• We have fabricated two- and three-dimensions silicon shapes and structures.
• The process is based on ion beam irradiation followed by electrochemical anodization.
• These structures are fabricated after a single step of etching of bulk silicon.
• Complex patterns are fabricated by controlling irradiation and anodization conditions.
• Thermal oxidation is very effective in reducing the surface roughness.

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.

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