Similarities and Differences of BTI in SiC and Si Power MOSFETs
Judith Berens, Magdalena Weger, Gregor Pobegen, Thomas Aichinger, Gerald Rescher, Christian Schleich, Tibor Grasser
Abstract
Bias temperature instability (BTI) is a serious reliability concern not only in 4H silicon carbide (4H-SiC) power MOSFETs, but also in Si technology. Even though previous studies presented large BTI drifts for some SiC devices compared to Si, we show that BTI in modern SiC may become uncritical by improved device processing. As will be shown, NBTI can even be reduced to a similar drift level as in Si power MOSFETs. Furthermore, we demonstrate that BTI in SiC and Si devices share many features such as a comparable time and voltage evolution. Thus, BTI in SiC MOSFETs can be described with the same empirical and simple physical models, and is therefore as predictable as for Si-based devices. In addition, this indicates that BTI in SiC and Si power MOSFETs is caused by the same physical origin of the degradation.