Profiling the boron distribution in asymmetric n +-p silicon photodiodes and a new concept for creating selectively sensitive photocells for megapixel color-image receivers

Abstract

The spectral photosensitivity of n+-p silicon photodiodes with a p+ layer implanted in the substrate is studied experimentally. It is demonstrated that such p+ doping effectively shifts the long-wavelength edge of the photosensitivity in the optical spectral range and the shift depends on the depth of the p+ layer. A new concept for creating selectively sensitive photocells for megapixel color-image receivers is proposed. The receivers are based on n+-p photodiode structures containing a few layers that are implanted at different depths and form desired color-separating potential barriers and lateral diffusion channels for collection of the minority carriers generated by photons of different colors.