Effect of electric field on primary dark pulses in SPADs for advanced radiation detection applications

In this paper, the single-photon avalanche diodes (SPADs) featuring three different p-well implantation doses (∅p−well) of 5.0×1012, 4.0×1012, and 3.0×1012 atoms/cm2 under the identical device layouts were fabricated and characterized to evaluate the effects of field enhanced mechanisms on primary dark pulses due to the maximum electric field. From the I–V curves, the breakdown voltages were found as 23.2 V, 40.5 V, and 63.1 V with decreasing ∅p−well, respectively. By measuring DCRs as a function of temperature, we found a reduction of approximately 8% in the maximum electric field lead to a nearly 72% decrease in the DCR at Vex = 5 V and T = 25 °C. Also, the activation energy increased from 0.43 eV to 0.50 eV, as decreasing the maximum electric field. Finally, we discuss the importance of electric field engineering in reducing the field-enhanced mechanisms contributing to the DCR in SPADs and the benefits on the SPADs related to different types of radiation detection applications.