Surface-roughness effect on capacitance and leakage current of an insulating film

Effects of surface roughness on electrical properties of a thin insulating film capacitor with one smooth electrode plate and one rough electrode plate are investigated. The electrode plate roughness is described in terms of self-affine fractal scaling through the roughness exponent α, the root-mean square (rms) roughness amplitude w, and the correlation length ξ. The electric field, capacitance, and leakage current show similar qualitative changes with the roughness parameters: they all increase as w increases, and also increase as either ξ or α decreases.