Scaling analysis of SiO₂/Si interface roughness by atomic force microscopy

The scaling behavior of SiO₂/Si interface roughness was investigated by atomic force microscopy. The rms value of the roughness increased as a power of the scale up to 100 nm with the scaling exponent of 0.3–0.5, and saturated at about 0.3 nm above the 100 nm scale. The scaling behavior of the observed roughness was well approximated by an exponential autocorrelation function with the correlation length of about 15 nm, but not by a Gaussian one. Such scaling behavior should be taken into account in theoretical calculation of surface roughness scattering, and also in metrology of roughness parameters.