Scanning tunneling microscope to evaluate supersmooth surface roughness

Our group has developed a surface roughness measuring system for supersmooth optics based on scanning tunneling microscopy techniques, which includes the assessment of two dimensional and three dimensional surface roughness parameters. The system has been applied to topographic mapping of superpolished Si wafer coated with single layer Mo film. The measuring precision of measured Rms, Ra and P-V value, if expressed with standards deviation (sigma) s, is 0.06 nm, 0.05 nm and 0.19 nm, respectively, which has achieved atomic resolution.