The invention concerns an image sensor comprising: a depth pixel (PZ) having: a detection zone (PD); a first memory (mem1) electrically coupled to the detection zone by a first gate (310); a second memory (mem2) electrically coupled to the detection zone by a second gate (314); and a third memory (mem3) electrically coupled to the detection zone by a third gate (316), wherein the first, second and third memories are each formed by a doped region sandwiched between first and second parallel straight walls (404, 406), the first and second walls of each memory having a conductive core adapted to receive a biasing voltage; and a plurality of 2D image pixels (P1 to P8) positioned adjacent to the depth pixel, wherein the first, second and third memories extend to form at least partial isolation walls between corresponding adjacent pairs of the 2D image pixels.