3D simulations and modeling of new low capacitance silicon pixel detectors

With signal to noise ratio (S/N) being a key parameter of a high performance detector, reducing the detector noise has been one of the main tasks in detector development. A new low capacitance silicon pixel detector is proposed, which is based on a new electrode geometry with reduced effective electrode area while keeping the sensitive volume unchanged. Detector electrical characteristics including electrostatic potential, electric field, full depletion voltage, and capacitance have been simulated in detail using a 3D TCAD tool. From these simulations and calculations, we confirm that the new detector structure has a much reduced capacitance (by a factor of 3) as compared to the traditional pixel detectors with the same sensitive volume. This reduction in detector capacitance can certainly improve the detector signal to noise ratio. However, the full depletion voltage for the new structure is larger than that of the traditional one due to the small electrode effect.