Experimental demonstration of non-destructive detection of IGBT fault positions by magnetic sensor

This paper presents a method for non-destructive detection of faults in an insulated-gate bipolar transistor by magnetic sensing. The method detects the magnetic field generated by the leakage electrical current that occurs at the broken gates of an insulated-gate bipolar transistor. A high-sensitivity magnetic sensor is used to detect the magnetic field to locate the corresponding fault positions. The magnetic probe is fully integrated into a chip by a 180-nm CMOS process and includes a magnetic pick-up coil, low-noise amplifier, mixer, and a low-pass filter. Magnetic scanning is performed on an insulated-gate bipolar transistor sample to locate the broken gate position. In addition, a visual confirmation of the broken gate is performed. Several post-processing steps are applied to the sample in order to confirm the scanning result of the proposed method. The experimental results show that our method can be used for non-destructive detection of faults in an insulated-gate bipolar transistor by magnetic scanning.