Characterization of the first double-sided 3D radiation sensors fabricated at FBK on 6-inch silicon wafers

Following 3D pixel sensor production for the ATLAS Insertable B-Layer, Fondazione Bruno Kessler (FBK) fabrication facility has recently been upgraded to process 6-inch wafers. In 2014, a test batch was fabricated to check for possible issues relevant to this upgrade. While maintaining a double-sided fabrication technology, some process modifications have been investigated. We report here on the technology and the design of this batch, and present selected results from the electrical characterization of sensors and test structures. Notably, the breakdown voltage is shown to exceed 200V before irradiation, much higher than in earlier productions, demonstrating robustness in terms of radiation hardness for forthcoming productions aimed at High Luminosity LHC upgrades.