Mechanism of breakdown voltage wavering in power MOSFET induced by silicon crystalline defect

This paper presents the impact of silicon crystalline defects generating mechanism of breakdown voltage degradation on low voltage vertical Power N-MOSFETs, functioning in avalanche mode. The physical defect determination is presented through a full failure analysis: it includes specific sample preparation, electrical characterization using EMMI techniques and physical characterizations using Scanning Electron Microscope, Transmission Electron Microscope and chemical delineation etches. Silicon crystal defects (edge dislocation and stacking fault) are found to be at the origin of the failure. Then, a discussion presents how the failure mechanism impacts the device structure and some possible root cause at the origin of the defect.