Room temperature writing of electrically conductive and insulating zones in silicon by nanoindentation

Conventional silicon devices are fabricated in the diamond cubic phase of silicon, so-called Si-I. Other phases of silicon such as Si-XII and Si-III can be formed under pressure applied by nanoindentation and these phases are metastable at room temperature and pressure. We demonstrate in this letter that such phases exhibit different electrical properties to normal (diamond cubic) silicon and exploit this to perform maskless, room temperature, electrical patterning of silicon by writing both conductive and insulating zones directly into silicon substrates by nanoindentation. Such processing opens up a number of potentially new applications without the need for high temperature processing steps.