Developments in the FBK Production of Ultra -Fast Silicon Detectors

In this contribution we present new developments in the production of Ultra Fast Silicon Detectors (UFSD) at Fondazione Bruno Kessler (FBK) in Trento, Italy. FBK after having in 2016 a successfully first production of UFSD sensors 300-micrometer thick, has produced in 2017 its first 50-micrometer thick UFSD sensors. These sensors use high resistivity Silicon on Silicon substrate and have different doping profile configurations of the gain layer based on Boron, Gallium, Carbonated Boron and Carbonated Gallium to obtain a controlled multiplication mechanism. The motivation of variety of gain layers it is to identify the most radiation hard technology to be employed in the production of UFSD for applications in high-radiation environments.