Abstract: A three-dimensional (3D) Trench detector and a method for fabricating the detector are disclosed. The 3D-Trench detector includes a bulk of semiconductor material that has first and second surfaces separated from each other by a bulk thickness, a first electrode in the form of a 3D-Trench, and a second electrode in the form of a 3D column. The first and second electrodes extend into the bulk along the bulk thickness. The first and second electrodes are separated from each other by a predetermined electrode distance, and the first electrode completely surrounds the second electrode along essentially the entire distance that the two electrodes extend into the bulk such that the two electrodes are substantially concentric to each other. The fabrication method includes doping a first narrow and deep region around the periphery of the bulk to form the first electrode, and doping a second narrow and deep region in the center of the bulk to form the second electrode.