Roughening of the Si/SiO2 interface during SC1-chemical treatment studied by scanning tunneling microscopy

The ${\mathrm{Si/SiO}}_{\mathrm{2}}$ interface morphology is observed with subnanometer resolution by an ultrahigh vacuum scanning tunneling microscope (STM). We analyze the roughness of the ${\mathrm{Si/SiO}}_{\mathrm{2}}$ interface for a chemical oxide film formed by a wet chemical process $({\mathrm{NH}}_{\mathrm{4}}{\mathrm{OH/H}}_{\mathrm{2}}{\mathrm{O}}_{\mathrm{2}}/{\mathrm{H}}_{\mathrm{2}}\mathrm{O}$ treatment). The oxide film is selectively removed by irradiating a field emission electron beam extracted from a STM tip at a temperature of 300–350 °C. We find that during the chemical process the roughness of the ${\mathrm{Si/SiO}}_{\mathrm{2}}$ interface increases with the treatment time.