Fast Optical Characterization of Microvoid Size in Hydrogenated Amorphous Silicon: Study on the Universal Applicability of the Correlation between the Microvoid Size and the Optical Constant

Recently, we have found that the microvoid size in a-Si:H, determined via positron annihilation lifetime spectroscopy (PALS), is systematically correlated with the optical constant, the peak value of ε2;ε2peak, obtained from spectroscopic ellipsometry. This indicates a possibility to establish a novel characterization method that allows the average size and density of microvoid to be estimated readily via spectroscopic ellipsometry. In this presentation, we demonstrate a new finding that the microvoid size and the ε2peak of a-Si:H films deposited under different conditions, even including the sort of apparatus, are on an identical curve if a-Si:H films are prepared without doping.