Ultra-large scale array silicon pixel sensors with uniform and low leakage current for advanced X-ray light sources

Abstract

The development of silicon pixel sensors (SPS) with high operating voltage, low leakage currents, and large arrays can contribute to improving the energy and spatial resolution of advanced X-ray light source detection systems. The Future Detection System comprises a hybrid-pixel detector with a collective resolution of 2048 × 2048 pixels, each measuring 100 μm× 100 μm. It consists of 16 p-i-n SPSs, where each sensor has an array size of 1024× 256 pixels. In this paper, the design of the pixel and guard rings is optimized to achieve uniform and ultra-low pixels leakage currents under high operating voltage. The high leakage current uniformity of the designed sensor is demonstrated through several tests conducted on small scale array SPS. The leakage current of the tested pixels is in the range of 0.50–0.55 pA at room temperature with less than 5% leakage deviation on the whole array. It is accompanied by breakdown voltages greater than 1000 V. The optimized 256× 128 pixel SPS showcases uniform leakage currents below 0.6 pA per pixel at room temperature, as evidence in both the edge and central pixels. The 1024× 256 pixels SPS is then manufactured based on the optimized design results. The obtained results show that the breakdown voltage is greater than 1000 V and the leakage current of the pixel is less than 2.5 pA. In addition, the interpixel capacitance of the sensor also reach an ultra-low level of 16 fF. This study paves the way for the development of a robust semiconductor device solution for applications where ultra-fast and large panel-pixel detectors in advanced X-ray light source detection systems are required.