Very small pixel pitch focal plane array and method for manufacturing thereof

An imaging device comprising:

• a first semiconductor layer having a first surface and a second surface;
• a first photodetector having a first implanted region formed in the first semiconductor layer and a pad formed over the first implanted region, the pad having a malleable metallic material;
• a readout circuit disposed over the first surface of the first semiconductor layer, the readout circuit having a plurality of contact plugs facing the first surface of the first semiconductor layer, a first of the contact plugs having a first base and a first prong extending from the first base and into the malleable metallic material of the pad of the first photodetector;
• a second semiconductor layer disposed below the second surface of the first semiconductor;
• a second photodetector having a second implanted region formed in the second semiconductor layer;
• and
• a metalized via extending through the first semiconductor layer and the second semiconductor layer and electrically connecting the second implanted region to a second of the contact plugs of the readout circuit.