Well structure engineering to improve the responsivity of p-on-n SiPM developed at KAIST-NNFC

This paper describes the electrical and optical properties of the p-on-n silicon photomultiplier (SiPM) developed at KAIST-NNFC. In particular, we present a comparison of the new and old versions in terms of several SiPM characteristics to highlight the improvements achieved through internal structure engineering. The new-version sensors were fabricated on a 200 mm n-doped epitaxial silicon wafer with an abrupt p+/n junction structure identical to that used in the old-version sensors using 0.18μm CMOS technology. Based on the previous work, several changes were applied to the improved sensors, such as rapid thermal processing (RTP) conditions and ion implantation conditions for junction formation. In the work, we demonstrate that the reverse current is reduced by more than a factor of 104 with the modified RTP conditions. Furthermore, we show that the breakdown voltage is decreased by nearly 20% and the PDE in the blue-light regime is enhanced by nearly a factor of two as a result of internal structure engineering.