CMOS PHOTODETECTOR ELEMENT WITH HIGH FILL FACTOR Russian patent published in 2009 - IPC H01L27/14 

FIELD: physics; conductors.

SUBSTANCE: invention can be used for making photosensitive digital and analogue devices. According to the invention, the CMOS photodetector element comprises a photodiode and transistors of the photodiode control circuit. According to the invention, the photodiode is formed by two layers: an embedded low-doped n-type layer (grown on a blank substrate of p-type conductivity, a p-type pocket forms on the surface of the given n-epitaxial layer), which serves as the body of the photodiode, and a surface n⁺-layer which is aligned with the embedded photodiode layer at a certain depth. The substrate and the p-type pocket are connected to an earth bus and the n-region of the photodiode is connected to the positive supply potential bus. The n⁺-region of the photodiode is the source of the control transistor of the photodetector element circuit. With the respective selection of doping levels of diffused layers and control voltages, the n-layer of the photodiode in accumulation mode appears completely depleted, which enables transfer of photogenerated charge carriers into the n⁺-layer of the photodiode through directed electric fields surrounding a considerable part of the body of the photodetector element.

EFFECT: increased sensitivity of the CMOS photodetector element and reduced noise.

6 dwg