A semiconductor sensor of ionizing radiation and/or particles, comprising: a substrate of a semiconductor material having a first doping; a bias layer formed upon a backside of said substrate, having a second doping of a type opposite to a type of said first doping; a backside bias electrode, formed on a free surface of said bias layer opposite to a surface of said bias layer in contact with said substrate; an intermediate layer formed upon a front side of said substrate, having a third doping greater than said first doping and of the same type thereof; first doped buried regions formed in depth in said intermediate layer, separated one from the other by spacing portions of said intermediate layer, said doped buried regions having a fourth doping of a type opposite to the type of said first doping; carrier collection regions formed in a front side of said spacing portions of the intermediate layer, fully surrounded therefrom and at a distance from said doped buried regions, said collection regions having a fifth doping greater than said third doping and of a same type thereof, and being extended in depth in said intermediate layer not more than said doped buried regions; collection electrodes, each formed upon a front side of a respective region of said carrier collection regions; first doped superficial regions (5p, 5n) formed upon said first doped buried regions up to a front-side of said intermediate layer; readout electronic circuits defined in a front side of said first doped superficial regions (5p, 5n), having electric terminals functionally connected with said collection electrodes to detect carriers, generated by ionizing radiation and/or particles into said substrate, collected by said collection regions. a substrate of a semiconductor material having a first doping; a bias layer formed upon a backside of said substrate, having a second doping of a type opposite to a type of said first doping; a backside bias electrode, formed on a free surface of said bias layer opposite to a surface of said bias layer in contact with said substrate; an intermediate layer formed upon a front side of said substrate, having a third doping greater than said first doping and of the same type thereof; first doped buried regions formed in depth in said intermediate layer, separated one from the other by spacing portions of said intermediate layer, said doped buried regions having a fourth doping of a type opposite to the type of said first doping; carrier collection regions formed in a front side of said spacing portions of the intermediate layer, fully surrounded therefrom and at a distance from said doped buried regions, said collection regions having a fifth doping greater than said third doping and of a same type thereof, and being extended in depth in said intermediate layer not more than said doped buried regions; collection electrodes, each formed upon a front side of a respective region of said carrier collection regions; first doped superficial regions (5p, 5n) formed upon said first doped buried regions up to a front-side of said intermediate layer; readout electronic circuits defined in a front side of said first doped superficial regions (5p, 5n), having electric terminals functionally connected with said collection electrodes to detect carriers, generated by ionizing radiation and/or particles into said substrate, collected by said collection regions.