The reflectivity of an etched silicon surface with pyramids: I. Theoretical model and its predictions

In the present paper, a 3D model is developed to evaluate the reflectivity of an etched surface with pyramids. This model determines primary and secondary reflections by tracing parallel light beams from the location of each surface element. The model is then applied to predict total reflectivity and area fraction of illumination as a function of the angle of incidence and mean pyramid height. The reduction in the reflectivity of a surface is obtained by increasing the mean pyramid height, or by increasing the angle of incidence, irrespective of the mean pyramid height. However, the reflectivity is asymptotic to a constant value as the angle of incidence is lowered to a sufficiently small value.