Breakdown Characteristics of CMOS Schottky Barrier Diode with Guard Ring

This study investigates the impact of guard ring installation on the breakdown performance of CMOS Schottky barrier diodes for the first time. Generally, a guard ring is adopted to improve leakage and breakdown characteristics, which define diode behavior under reverse bias. Measurement results showed that the breakdown voltage was -11.4 V for Schottky barrier diode with guard ring, approximately 16% lower than the -13.6 V of Schottky barrier diode without guard ring. This indicates that while the guard ring helps reduce leakage current, it slightly degrades breakdown performance in the CMOS Schottky barrier diode. To understand the cause of this breakdown voltage reduction, TCAD simulations were conducted. The simulation also showed a 16% reduction in breakdown voltage. Additionally, the simulation revealed a stronger electric field between the cathode and the separator with the installation of a guard ring. This increased electric field may account for the slightly lower breakdown voltage observed in the Schottky barrier diode with guard ring. Further analysis and design optimization are needed to enhance breakdown voltage while maintaining the leakage-reducing benefits of the guard ring.