Analysis of displacement damage effects on MOS capacitors

Displacement damage effect on MOS capacitors is analyzed in this work with the aid of TCAD simulations. A noticeable capacitance reduction in the accumulation mode is observed in the High Frequency C–V characteristic curve after a 24 GeV proton irradiation. This effect is clearly distinguishable from ionizing damage effects, otherwise negligible under the specific conditions of the experiment. The capacitance reduction is identified with the increase of the substrate resistivity, due to the modification of its effective doping concentration. Supported on a well-established traps model, the expected displacement damage defects are simulated as a function of the fluence, allowing the identification of donor trap levels as the responsible of the phenomenon for p-type substrate MOS capacitors.