SINGLE PHOTON AVALANCHE DIODE AND ARRAY OF SINGLE PHOTON AVALANCHE DIODES

摘要

A single photon avalanche diode, SPAD, comprises an active area (10) which is arranged to generate a photon triggered avalanche current. A cover (12) is arranged on or above the active area (10). The cover (12) shields the active area (10) from incident photons. The cover (12) comprises a stack of at least the first and a second metal layer (13, 14). At least one of the metal layers (13, 14), e.g. the first metal layer (13), comprises an aperture (15). The metal layers (13, 14) are arranged in the stack with respect to an optical axis (OA) such as to open an effective aperture (18) along the optical axis (OA). By way of the effective aperture (18) a portion (19) of the active area (10) is exposed to incident photons being incident along the optical axis (OA). The effective aperture (18) is smaller than the aperture (15) arranged in the first metal layer (13).