Low-temperature technique of thin silicon ion implanted epitaxial detectors

International audienceA new technique of large-area thin ion implanted silicon detectors has been developed withinthe R&D performed by the FAZIA Collaboration. The essence of the technique is the application of a lowtemperaturebaking process instead of high-temperature annealing. This thermal treatment is performedafter B+ ion implantation and Al evaporation of detector contacts, made by using a single adjustedAl mask. Extremely thin silicon pads can be therefore obtained. The thickness distribution along theX and Y directions was measured for a prototype chip by the energy loss of α-particles from 241Am(Eα = 5.5MeV). Preliminary tests on the first thin detector (area ≈ 20 × 20mm2) were performed atthe INFN-LNS cyclotron in Catania (Italy) using products emitted in the heavy-ion reaction 84Kr(E =35AMeV)+112Sn. The ΔE−E ion identification plot was obtained using a telescope consisting of our thinΔE detector (21 μm thick) followed by a typical FAZIA 510 μm E detector of the same active area. Thecharge distribution of measured ions is presented together with a quantitative evaluation of the quality ofthe Z resolution. The threshold is lower than 2AMeV depending on the ion charge