Failure Analysis of Dielectric Material Defects Inside IGBT Chips

In this paper, the failure analysis of IGBT chips was conducted via comprehensive techniques, the micron-scale dielectric material defects inside the IGBT chips of IGBT modules were exposed and analyzed. Meanwhile, the physics of failure was discussed briefly, with the failure mechanism derived. For the first failed IGBT chip, the gate oxide layer and dielectric layer defects were characterized as a cavity located in the active area, which might result in partial discharge after the high temperature screening test. While for the second failed IGBT chip, a crack across between the dielectric layer and polysilicon field plate in the field limiting rings of the termination zone, this probably leads to electric field modification, which is further enhanced by moisture penetration.