Optical method for calculating the dopant concentration of doped amorphous semiconductors

An optical method is proposed to calculate the dopant (e.g., boron or phosphorus) concentration in doped amorphous semiconductors. The basic principle of this method is that the effective density of valence electrons and the coordination number of the samples could be obtained by f -sum rule and dispersion energy model, respectively. A computational model is derived from this method and applied to doped amorphous silicon (a-Si:H) films with the results of spectroscopic ellipsometry and Fourier transform infrared spectroscopy measurements. It is found that the predicted concentrations of boron and phosphorus in doped a-Si:H samples are quite consistent with the actual results from secondary ion mass spectroscopy test, for the samples with the dopant content higher than 10 21 cm −3 .