Gate-controlled diodes for characterization of the Si–SiO2 interface with respect to surface effects of silicon detectors

In future high-energy physics experiments silicon detectors with a high spatial resolution will be used for tracking close to the interaction point. Besides crystal damage, the surface damage caused by ionizing irradiation is very important for the long-term performance of these devices. Therefore, systematic characterization of surface effects is necessary. For these investigations we designed a test field consistent of MOS structures and gate-controlled diodes to be produced with different vendors. A new gate-controlled diode with different current and capacitance measurement options will be introduced and first results of parameters evaluated on the unirradiated device as well as after irradiation with low energetic electrons, neutrons and charged hadrons will be presented. The gate-controlled diode with new features has been shown to be a powerful tool to investigate the oxide and interface quality before and after irradiation.