Characterization of irradiated test structures for the CMS tracker upgrade

The CMS collaboration is currently conducting a campaign to identify radiation-hard materials for the CMS tracker upgrade. Several different test structures (TS) and sensors have been designed for a 6 inch wafer layout. These wafers were produced by an industrial supplier (Hamamatsu Photonics K.K.) and differ by their bulk material (Float Zone, Magnetic Czochralski and CVD-Epi), thickness (from 50 $\mu$m to 320 $\mu$m) and N/P-type doping. These TS consist of different microelectronic devices like diodes, resistors or MOS structures. They enable the extraction of parameters which are not accessible in a silicon detector and allow the assessment of the quality of the sensors which are produced on the same wafer. The TS have been irradiated with protons and neutrons to emulate the radiation damage caused by the particle fluence inside the CMS tracker after 10 years of operation. This contribution will present measurements of non-irradiated and irradiated test structures at different fluencies. The changes of the properties of the microelectronic devices will be discussed as well as the design of the TS.