Improve the Breakdown Voltage of Silicon Pixel Sensor With Optimized Multi-Guard Rings

The silicon pixel sensor (SPS) for X-ray free electron laser detection requires ultra-high operating voltage. In this paper, for an optimized multi-guard rings, a SPS with ultra-high breakdown voltage and low leakage is obtained. The effect of the arrangement of the multi-guard rings on the SPS breakdown is investigated by TCAD simulation. It is found that SPS with a gradually increasing gap from inner ring to outer ring has a higher breakdown voltage. Guided by this, the multi-guard ring structure of SPS is optimized and applied into the manufacture of devices. Finally, the optimized SPS exhibits an ultra-high breakdown voltage of exceeding 1,800 V; and the dark current of per pixel is approximately 2.0 pA at a bias voltage of 1,000 V.