The invention provides a semiconductor device (11) for radiation detection, which comprises a substrate region (1) of a substrate semiconductor material, such as silicon, and a detection region (3) at a surface of the semiconductor device (11), in which detection region (3) charge carriers of a first conductivity type, such as electrons, are generated and detected upon incidence of electromagnetic radiation (L) on the semiconductor device (11). The semiconductor device (11) further comprises a barrier region (2,5,14) of a barrier semiconductor material or an isolation material, which barrier region (2,5,14) is an obstacle between the substrate region (1) and the detection region (3) for charge carriers that are generated in the substrate region (1) by penetration of ionizing radiation (X), such as X-rays, into the substrate region (1). This way the invention provides a semiconductor device (11) for radiation detection in which the influence on the performance of the semiconductor device (11) of ionizing radiation (X), such as X-rays, that penetrates into the substrate region (1) is reduced.