Microstructure evolution during silicon oxidation at room temperature under composite ion beam irradiation

In this work, we studied the silicon microstructure evolution during its oxidation under composite beam ion irradiation at room temperature. It was found that when the composite ion beam was formed by hydrogen and dry oxygen mixture at low doses (∼1018 cm−2), a porous silicon layer was formed. During irradiation, the pore size gradually reduced and at a dose of ∼1020 cm−2 pores disappear completely, and an uniform layer of silicon oxide was formed. If residual gases and hydrogen are used to generate a composite ion beam, the formation of porous silicon is not found. The final thickness of irradiation-induced silicon oxide corresponded to the projected range of protons at a given energy in both cases.