<title>Equivalent circuit modeling of metal-semiconductor-metal photodiodes with transparent conductor electrodes</title>

Abstract

Metal-semiconductor-metal (MSM) photodiodes with electrodes fabricated from the transparent conductor cadmium tin oxide (CTO) have been shown to double photoresponsivity. Their bandwidths, however, are significantly lower than those of MSMs fabricated with standard Ti/Au contacts. Though MSMs are generally believed to be limited by the transit time of electrons, it is possible the larger resistivity of CTO has become a significant factor, making the MSMs RC time constant limited instead. Previous models of MSMs only account for one of the two back-to-back Schottky diodes. A new model which takes into account both the forward and reverse biased junctions has been developed from the small signal model of a Schottky diode. This new model was fit to data obtained from S-parameter measurements, and incorporates both the transit time response and RC time constant response.© (1997) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.