Development of multi-guard ring-equipped p+–n Si microstrip sensors for the SiD detector at the ILC

Si sensors in future high-energy physics experiments will encounter an extremely harsh radiation environment. In lepton colliders, the dominant background from electron–positron pairs can be managed with modern Si technology, but there is also a potentially dangerous neutron background. Specifically, the estimated neutron background is around 1–1.6 × 1010 1-MeV equivalent neutrons cm−2 year−1 for the Si microstrip sensors to be used in the innermost vertex detectors of the International Linear Collider (ILC). This causes bulk damage in the Si sensors due to the non-ionization energy loss and is of much greater importance in determining the viability of their long-term operation. For reliable operation, such sensors will need to operate at high reverse biases, far beyond the full depletion voltages, which can lead to the sensor breakdown. Multi-guard ring structures have evolved as a powerful technique to improve the breakdown performance of these sensors. In this work, a comprehensive approach towards the understanding of multi-guard ring structures is followed by simulating several structures with different layouts. The potential and field distributions help in optimizing design parameters