Bispectral multilayer photodiode detector and method for manufacturing such a detector

A bispectral detector for detecting a first and a second electromagnetic radiation ranges, comprising:

• a stack of upper and lower semiconductor layers of a first conductivity type in order to absorb a first and a second electromagnetic radiation ranges respectively, separated by an intermediate layer that forms a potential barrier between the upper and lower layers;
• semiconductor zones of a second conductivity type opposite to the first conductivity type and implanted in the upper layer and in the lower layer, each semiconductor zone in the lower layer being implanted at least partially in the bottom of an opening that passes through the upper layer and intermediate layer;
• and
• electrical conductor elements connected respectively to semiconductor zones in order to collect the electrical charges in these zones;
• wherein at least part of each opening that passes through the upper layer is separated from said upper layer by a semiconductor cap layer of the second conductivity type:
• whereof the concentration of dopants of the second conductivity type is greater than 1017 cm−3;
• and
• whereof the thickness is chosen as a function of said concentration so that it exceeds the minority carrier diffusion length in the cap layer.