Silicon Sensor Developments for the CMS Tracker Upgrade

As the high luminosity phase of the LHC is approaching, the CMS collaboration started research for the future silicon sensor baseline for the CMS Tracker phase II upgrade. Wafers of various materials (float-zone, magnetic czochralski and epitaxial), thicknesses from $320{\rm \mu m}$ down to $50{\rm \mu m}$ and n-bulk or p-bulk doping have been ordered at one manufacturer, HPK, for good comparison. Alongside, the feasibility of processing sensors with double metal routing on 6'' wafers is explored. Different structures answer different questions covering aspects from radiation hardness to layout issues in this evaluation. A mixed irradiation program with protons and neutrons probes radiation hardness representing a mixture of charged and neutral hadrons expected in the CMS tracker after an integrated luminosity of $3000{\rm fb^{-1}}$ at several radii. This contribution gives an overview of the first proton irradiated diodes. Furthermore, a sensor with integrated pitch adapter on a second metal layer is characterised and presented for the first time.