3D-Si single sided sensors for the innermost layer of the ATLAS pixel upgrade

The LHC is expected to reach luminosities up to $3000{\mathrm{fb}}^{-1}$ and the innermost layer of the ATLAS upgrade plans to cope with higher occupancy and to decrease the pixel size. 3D silicon (3D-Si) sensors are a good candidate for the innermost layer of the ATLAS pixel upgrade since they exhibit good performance under high fluences and the new designs will have smaller pixel size to fulfill the electronics specifications. Detectors located at large $\eta$ angles, far from the interaction point, will receive the particles almost perpendicularly to the column. In order to have a more precise detection at those positions, thinner 3D detectors are proposed. The thickness of the active wafer can be reduced according to the requirement of the experiments. The first production of these detectors was done on 150 $\mu$m p-type Silicon On Insulator (SOI) wafer with a p-type backside implant and the electrical characteristics and charge collection measurements are reported in this paper.