Improvement of sensitivity for power cycle degradation by a new device structure

This paper reports a demonstration of a new sensor device structure designed to increase the current change for detecting power cycle degradation. In a previous study, a low-cost and high-accuracy sensor device was proposed, which can be integrated into power device chip. The sensor device consists of a Schottky barrier MISFET. Power cycling degradation is detected by a decrease in the drain current of the SB-MISFET, as repetitive mechanical stress increases the interface state density of the MIS gate. The sensor devices demonstrated the basic operation of a decrease in drain current due to repetitive mechanical stress. However, the change in current was only 4 to 5 times smaller than initial current. In this study, it is clarified that this current change is limited by leakage current, and a new structure is proposed to suppress this leakage current. The proposed structure achieved a current change 12 to 13 times smaller than the initial current, due to the leakage current 1/8 times smaller compared to the conventional structure.