Influence of Boron Diffusion on Photovoltaic Parameters of n+-p-p+ Silicone Structures and Based Photodetectors

The paper investigates the photovoltaic properties of the silicon n+-p-p+-structures and photodiodes made on their basis. It was found that boron diffusion to the reverse side of the substrate, in addition to creating an ohmic contact, generates generation-recombination centers, which allows to reduce the dark current of photodiodes and increase their responsivity. It was also found that chemical dynamic polishing of the back side of the substrates before boron diffusion allows to eliminate a significant number of defects and improve the final parameters of the products. In samples without a p+-layer and samples not polished from the back side, a breakdown of the p-n junction is observed on the back side, which is caused by the expansion of the space charge region to the entire thickness of the substrate and the achievement of a defective back side of the crystal.