An optical semiconductor device includes, in a zone (5), a structure of photosensitive diodes including a matrix (6) of lower electrodes (7), an intermediate layer (9) made of a photosensitive material formed on the matrix of lower electrodes and at least one upper electrode (10a) formed on the intermediate layer, in which an electrical connection (3a) includes at least one electrical contact pad (7a) and at least one electrical connection pad (16a) are produced beneath the intermediate layer, at least one electrical connection via (14) is produced through the intermediate layer and connects the upper electrode to the electrical contact pad and at least one well (15a) is formed outside the zone (5) and passes through at least the intermediate layer (9) in order to expose the electrical connection pad (16a). Also provided is a process for fabricating such a device.