A semiconductor sensor device, comprising: - a semiconductor substrate having a main surface, - a photodiode arranged in the substrate at or near the main surface, the photodiode generating an electric signal in response to incident radiation, - a further photodiode, the further photodiode generating a further electric signal in response to the incident radiation, - the photodiode and the further photodiode being formed and arranged in such a manner that in case of incident ultraviolet radiation the electric signal from the photodiode is larger than the further electric signal from the further photodiode, and - the electric signal from the photodiode being attenuated by the further electric signal and thus yielding an electric signal primarily measuring the incident ultraviolet radiation, characterized in that - the further photodiode is arranged in the substrate at or near the main surface, - doped wells of a first type of electric conductivity are formed in the substrate at or near the main surface, - pn-junctions are arranged in or at the doped wells, the pn-junctions forming the photodiode and the further photodiode, - a contact region or a channel-B-region is arranged in the doped well of the further photodiode, the contact region or the channel-B-region being doped with a doping concentration that increases towards the main surface, - a contact region doped for the second type of conductivity is arranged outside the doped well, and - if the contact region is provided, the pn-junctions are formed at boundaries of the doped wells, and the contact region is doped for the first type of conductivity and extends over most of the area occupied by the doped well, and if the channel-B-region is provided, the pn-junction of the further photodiode is formed at a boundary of the channel-B-region, which is doped for a second type of conductivity opposite to the first type of conductivity and extends over most of the area occupied by the doped well or comprises a pattern of stripes or islands. - a semiconductor substrate having a main surface, - a photodiode arranged in the substrate at or near the main surface, the photodiode generating an electric signal in response to incident radiation, - a further photodiode, the further photodiode generating a further electric signal in response to the incident radiation, - the photodiode and the further photodiode being formed and arranged in such a manner that in case of incident ultraviolet radiation the electric signal from the photodiode is larger than the further electric signal from the further photodiode, and - the electric signal from the photodiode being attenuated by the further electric signal and thus yielding an electric signal primarily measuring the incident ultraviolet radiation, characterized in that - the further photodiode is arranged in the substrate at or near the main surface, - doped wells of a first type of electric conductivity are formed in the substrate at or near the main surface, - pn-junctions are arranged in or at the doped wells, the pn-junctions forming the photodiode and the further photodiode, - a contact region or a channel-B-region is arranged in the doped well of the further photodiode, the contact region or the channel-B-region being doped with a doping concentration that increases towards the main surface, - a contact region doped for the second type of conductivity is arranged outside the doped well, and - if the contact region is provided, the pn-junctions are formed at boundaries of the doped wells, and the contact region is doped for the first type of conductivity and extends over most of the area occupied by the doped well, and if the channel-B-region is provided, the pn-junction of the further photodiode is formed at a boundary of the channel-B-region, which is doped for a second type of conductivity opposite to the first type of conductivity and extends over most of the area occupied by the doped well or comprises a pattern of stripes or islands.