Avalanche photodiode semiconductor structure for receiving electromagnetic radiation in a given wavelength range and comprising: - a first so-called absorption semiconductor area, of a first type of conductivity having a first face for receiving the electromagnetic radiation and a second face opposite the first face, the semiconductor material in which is formed said first area having an energy band gap suitable for allowing the absorption of the electromagnetic radiation, - a second so-called multiplication semiconductor area, in contact with the second face of the first area, the second area having a majority carrier concentration that is less than that of the first area, said second area being suitable for providing a multiplication of carriers by impact ionisation that is preponderant for one type of carrier, - a third so-called collection semiconductor area, in contact with the second semiconductor area 310), said third area being of a second type of conductivity opposite the first type of conductivity and having a majority carrier concentration that is greater than that of the second semiconductor area, the structure being characterised in that the second area comprises at least two subparts (321, 322), a first subpart through which the second area is in contact with the first area and a second subpart connecting the first subpart to the third area, the second subpart being suitable for having a mean carrier multiplication rate by micrometre that is greater than the mean carrier multiplication rate of the first subpart, and preferentially greater than 3 times, 5 times, even 10 times the mean carrier multiplication rate by micrometre of the first subpart, wherein the second subpart is made from a semiconductor material having an energy band gap that is less than that of the semiconductor material in which is formed the first subpart in such a way as to have the mean carrier multiplication rate by micrometre greater than that of the first subpart, wherein the first and the second subpart (321, 322) are made from mercury-cadmium tellurides of the Cd x Hg 1-x Te type with proportions x in cadmium that are different from one another, and wherein the first and the second subpart (321, 322) of the first area are both layers of which the minimum thickness is greater than 200 nm. - a first so-called absorption semiconductor area, of a first type of conductivity having a first face for receiving the electromagnetic radiation and a second face opposite the first face, the semiconductor material in which is formed said first area having an energy band gap suitable for allowing the absorption of the electromagnetic radiation, - a second so-called multiplication semiconductor area, in contact with the second face of the first area, the second area having a majority carrier concentration that is less than that of the first area, said second area being suitable for providing a multiplication of carriers by impact ionisation that is preponderant for one type of carrier, - a third so-called collection semiconductor area, in contact with the second semiconductor area 310), said third area being of a second type of conductivity opposite the first type of conductivity and having a majority carrier concentration that is greater than that of the second semiconductor area,