Thin detectors have been proposed to investigate the possibility to limit the full depletion voltage and the leakage current of heavily irradiated silicon devices. In this work we compare typical silicon detectors (p–n junctions over a 300 μm thick substrate) with thinned devices (50–100 μm of thickness). In order to investigate the performances of these structures, simulations have been carried out using the ISE-TCAD DESSIS device simulator. The so called three-level model has been used to investigate the effects of the radiation fluence on charge collection efficiency of thin and thick silicon structures. For each thickness, we simulate the hit of a minimum ionizing particle and then we calculate the current at the diode's electrode. We consider a 7× 10 11 cm− 3 n-doped substrate (a high resistivity substrate); all the structures are composed of a 40 μm diode contact and a 15 μm distant …