New developments on 3D detectors at IRST

We report on the latest results from the development of 3D silicon radiation detectors at IRST (Trento, Italy). A new detector concept has been defined, namely 3D-DDTC (Double-side Double-Type Column): it involves alternate etching of columnar electrodes of both doping types from both wafer sides, and stopping at a short distance (d) from the opposite surface. Simulations prove that, if d is kept small with respect to the wafer thickness, this approach can yield charge collection properties comparable to those of standard 3D detectors, with the advantage of a simpler fabrication process. Two wafer layouts (including strip detectors, pixel detectors, and test structures) have been designed with reference to this technology, and two fabrication runs have been fabricated. Simulation results and preliminary experimental results from the characterization of test structures from the first 3D-DDTC batch are reported.