R&D for new silicon pixel sensors for the High Luminosity phase of the CMS experiment at LHC

The High Luminosity upgrade of the CERN LHC collider (HL-LHC) demands a new high-radiation-tolerant solid-state pixel sensor capable of surviving fluencies up to a few 10(16) n(eq)/cm(2) at similar to 3cm from the interaction point. To this extent. the INFN ATLAS-CMS joint research activity, in collaboration with Fondazione Bruno Kessler (FBK), is aiming at the development of thin n-in-p-type pixel sensors for the HL-LHC. The R&D covers both planar and single-sided 3D columnar pixel devices made with the Si-Si Direct Wafer Bonding technique, which allows for the production of sensors with 100 mu m and 130 mu m active thickness for planar sensors, and 130 mu m for 3D sensors, the thinnest ones ever produced so far. The first prototypes of hybrid modules, bump-bonded to the present CMS readout chip, have been tested on beam. The first results on their performance before and after irradiation are presented.