Blue enhanced vertically stacked quad junction photodetector with opto window

A vertically stacked quad junction photodetector (PD) with an enhanced spectral responsivity for blue light is presented. This PD is implemented in a 0.35 μm high voltage complementary metal-oxide semiconductor (CMOS) technology. In addition, an optical window, an antireflection coating and a modified p⁺ doping are used to attain the enhancement for blue light. The proposed PD is compared against other state of the art implementations and characterised for its spectral response.