Technology development of 3D detectors for high-energy physics and imaging

Various fabrications routes to create ‘3D’ detectors have been investigated and the electrical characteristics of these structures have been compared to simulations. The geometry of the detectors is hexagonal with a central anode surrounded by six cathode contacts. A uniform electric field is obtained with the maximum drift and depletion distance set by electrode spacings rather than detector thickness. This should improve the ability of silicon to operate in the presence of the severe bulk radiation damage expected in high-energy colliders. Moreover, 3D detectors made with other materials (e.g. GaAs, SiC) may be used, for example, in X-ray detection for medical imaging. Holes in the substrate were made either by etching with an inductively coupled plasma machine, by laser drilling or by photochemical etching. A number of different hole diameters and thickness have been investigated. Experimental characteristics have been compared to MEDICI simulations.