Morphology of phosphorous-implanted p-type silicon electrochemically etched in HF electrolyte

The influence of the initial Si surface state on pore formation has been studied. For this purpose, samples were implanted by phosphorous ions at different doses and energies. Electrochemical characterisations and scanning electron microscopy (SEM) observations were made on phosphorous-implanted p-Si during the first stages of anodisation. After a short anodisation period in HF electrolyte, the topography of the implanted surface exhibits pyramidal structures, while the adjacent virgin silicon remains undisturbed. The result suggests that the anisotropic etching is associated with defects induced by the phosphorous ion implantation.