A new approach to the optimal design of multiple field-limiting ring structures

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 maximum breakdown voltage for Si detectors operating at very high bias due to the extremely hostile radiation environment of next generation experiments such as LHC. The performance of Si-microstrip detectors can be improved by implementing floating field-limiting rings around the active detector area. A simulation study has been carried out to evaluate the distribution of breakdown voltage as a function of guard-ring spacing (GS). The purpose of this work is to find a criterion to optimize GS for multiple ring structures incorporating various physical and geometrical parameters as an aid to design optimization. Using this criterion the optimum spacing of guard rings for multiple ring structures was obtained. The proposed criterion is very robust and is insensitive to the number of guard rings, junction depth and radiation damage. The simulation results for the seven-ring design agree well with experimental measurements. (21 refs)