Porous semiconductor micropatterns formed on focussed ion beam implants

In this work we report a principle that allows one to write visible light e mitting silicon patterns of arbitrary shape down to the sub-micrometer scal e. We demonstrate that porous Si growth can electrochemically be initiated preferentially at surface defects created in an n-type Si substrate by Si+ ion bombardment. Using a focused ion beam (FIB) as a source of ions, arbit rary defect patterns can be written into a substrate. The growth of light e mitting porous silicon is then selectively achieved by an electrochemical t reatment which triggers Si dissolution only at these defect sites. The sele ctivity of the electrochemical dissolution reaction can be attributed to a facilitated Schottky barrier breakdown at the implanted surface defects whi ch leads to the desired pore formation in confined surface areas.