Investigation of BVdss instability in trench power MOSFET through DLTS, electrical characterization and TCAD simulations

In this paper, we investigated the drain to source breakdown voltage (BVdss) instability during avalanche current drain stress of Shielded Gate MOSFET (SG-MOSFET) structure and we propose a new methodology to correlate electrical results to TCAD simulations. The presence of positive charged states at the Field Plate (FP) oxide/Si interface was confirmed by Capacitance Deep Level Transient Spectroscopy (C-DLTS). Thus, it was implemented in TCAD simulations that predict the experimental behavior of two architectures. Thanks to these results, walk-in contributors were discriminated to suggest a pathway to increase device robustness with a slight Ron impact.