Study of surface effects in the operation of 3D microstrip detectors with ultra-thin silicon substrates

U3DTHIN silicon is a proficient candidate for the particle analyzers for plasma diagnosis for the future ITER fusion reactor. The low full depletion of the 3D electrodes geometry implemented in these detectors as well as their low capacitances make them suitable for the tasks of ion detection they are being proposed in this work. Their electrical properties have been simulated in different configurations to know their working behavior. Both aluminum strips and oxide surface charge play important roles in the electrical behavior of these detectors. The field plate effect provided by the metallizations makes the potential and electric field to have distributions parallel to the aluminum strips, while the electron channels formed by electrons attracted by the positive charge located at the Si/SiO₂ interface make the detectors require higher voltages to deplete those inversion layers to effectively fully deplete the sensors. This surface effect is more important if the sensor is thinner due to the proximity of both top and bottom electron layers.