Photosensitive structure with charge amplification

Abstract

Presented invention describes the approach for manufacturing of the pixels for solid state imaging devices possessing a photon detection efficiency superior to those currently available. Formation of a bipolar junction transistor (BJT) in close vicinity of the photodiode in such a way that accumulation area of the photodiode also represents its collector region allows for conversion of the photo carriers which cannot be accumulated in a regular 4T pixel, usually holes, into complimentary type carriers, usually electrons, that can be stored, read out and converted to electric signal. This transistor can be formed, for example, by creating a n+ region inside the surface p layer of the pinned photodiode. In the described structure the accumulation region is isolated from the surface and operation of the new pixel is otherwise similar to the 4T pixel operation. As a result, both main advantages of 4T pixel: low dark current and kTC noise cancellation are, therefore, preserved.

Dependencies are inferred from the claim text.