Development of Radiation Hard Sensors

The trackers of the present LHC experiments mainly use silicon pixel detectors in the innermost regions close to the interaction point, while silicon micro-strip detectors are used at larger radii. The next phases of the LHC will present new challenges for the operation of the tracking detectors in terms of radiation levels and data rates. For ATLAS, CMS and LHCb radiation levels will amount to levels of the order of hundreds of Mrad and 10^16 NIEL (1 MeV neutron equivalent per cm^2) in the innermost layers. Higher granularity and a reduction in material budget especially for the layers close to the IP are under development to further improve the impact parameter resolution. The choice of sensors for the trackers will be driven by the need to meet these requirements. A short overview on the status of the R&D on silicon sensors suitable for this challenging environment will be given, covering the presently used but also newly emerging technologies such as CMOS based silicon sensors. The capabilities of technologies to meet the HL- LHC demands will be assessed.