In-operando x-ray topography analysis of SiC metal–oxide–semiconductor field-effect transistors to visualize stacking fault expansion motions dynamically during operations

Abstract

We developed an in-operando x-ray topography method for dynamically visualizing single Shockley-type stacking fault (1SSF) expansion motions in silicon carbide (SiC) metal–oxide–semiconductor field-effect transistors (MOSFETs) during their operations and investigated the effect of the operating condition applied to the body diodes in SiC MOSFETs on dislocation glide velocity. In-operando x-ray topography observations were carried out in reflection geometry, and a high-resolution x-ray camera was used as a detector to record topographies dynamically. The sequence of 1SSF expansion motions in the SiC MOSFETs was observed at a high resolution of 1 s in x-ray topographies, which is sufficient to analyze the dislocation glide velocity of a 1SSF expansion. The observation results of changing the forward current density applied to the body diodes in SiC MOSFETs revealed that each triangular and bar-shaped 1SSF expands at different forward current densities. The 1SSF expansion timings also differed, even in the same chip under the same current density. The dislocation glide velocity of each expanded 1SSF in SiC MOSFETs was extracted, and it increased with the forward current density. Our method enables the dynamic visualization of bipolar degradation in SiC MOSFETs during their operations, and we can accurately obtain the information of when, where, and which 1SSF expands in a SiC MOSFET.