Study of various high voltage protection structures for reduction of the insensitive region of silicon sensors designed for extreme radiation tolerance

Abstract

We studied several devices with different distances of the sensitive region to the cut edge after severe hadron irradiation. They have been characterized in term of the bias voltage drop on the various guard ring (GR) structures and their charge collection performance.Current pixel detectors are made with n-type silicon with n-side readout. This geometry requires backplane processing for implanting GR structures on the backplane of the sensor. This increases the cost and the complexity of the device, but on the other hand offers GR structures on both sides, with possibly a more efficient reduction of the edge potential and beneficial effects on reducing the insensitive area. We present the comparison of n-in-p and n-in-n detectors with similar geometry to show the effect of the double GR structure before and after hadron irradiation.