An embodiment of a Geiger-mode avalanche photodiode, having: a body made of semiconductor material of a first type of conductivity, provided with a first surface and a second surface and forming a cathode region; and an anode region of a second type of conductivity, extending inside the body on top of the cathode region and facing the first surface. The photodiode moreover has: a buried region of the second type of conductivity, extending inside the body and surrounding an internal region of the body, which extends underneath the anode region and includes the internal region and defines a vertical quenching resistor; a sinker region extending through the body starting from the first surface and in direct contact with the buried region; and a contact region made of conductive material, overlying the first surface and in direct contact with the sinker region.