Techniques of Improving the Breakdown Voltage of Si Microstrip Preshower Detector

In this paper, a computer based analysis is performed to study layout solutions aimed at increasing the breakdown voltage in Si microstrip detectors. For optimum performance, it is crucial to achieve the maximum breakdown voltage for Si detectors that operate at very high bias due to extremely hostile radiation environment of LHC. The breakdown performance of Si microstrip detectors can be improved by implementing floating field-limiting rings (FLR) and metal-overhang structures around the active detector area. In the present work, we optimize various physical and geometrical parameters for improving the breakdown voltage. In order to optimize the guard ring spacing for multiple ring structure, we have studied the electrical properties of Si detector with seven guard rings in six different layouts. It is shown that an optimum value exists for oxide thickness and junction depth to realize maximum breakdown voltage in structures with overhanging metal strips. The simulated results are compared with the experimental data and good agreement between the two is observed.