RD50 Collaboration: Recent results on developing very high radiation resistant silicon detectors

For the luminosity upgrade of the Large Hadron Collider (SLHC), the present LHC experiment tracking systems, based on semiconductor detectors, need to be replaced. The new challenge will be the extreme radiation hardness requirement of up to $1 \times 10^{16} \rm{n}_{eq} /cm^2$. The detectors will suffer from high radiation damage during their life time and will require radiation hard technologies to guarantee accurate track reconstruction. Current silicon sensors can operate up to $10^{15} \rm{n}_{eq} /cm^2$ because their radiation degradation could be balanced by increasing the oxygen amount of Float-Zone silicon substrates and high operating voltages are possible due to multi guard-rings geometry. Such devices are installed and running in the CERN Large Hadrons Collider (LHC) experiments. In the frame of the RD50-CERN Collaboration much work is in progress to extend this limit to $10^{16} \rm{n}_{eq} /cm^2$ in order to use silicon technology also in experiments at the proposed SLHC. This paper presents recent results of the RD50- Collaboration on radiation hard technologies developed on Float Zone, epitaxial and Magnetic Czochralski n- and p-type silicon sensors. Their charge collection efficiency after proton, neutron and mixed irradiation has been determined and new technology 3D detectors have been produced and studied as well. For high fluences microscopic defects have been also investigated and compared to the detection capability of the irradiated sensors