Influence of design parameters on the short-circuit ruggedness of SiC power MOSFETs

Abstract

Abstract-This work aims to present an investigation on short-circuit (SC) failure behaviour of SiC Power MOSFETs due to the onset of thermal runaway. As inferable from experimental outcomes, it is related to the formation of hotspot, whose exact location is mainly unpredictable and dictated by device structure and design parameters non-uniformities. TCAD simulations were performed to examine the impact of some parameters mismatch on hotspot formation and failure occurrence.

Thermal simulations of SiC MOSFETs under short-circuit conditions: influence of various simulation parameters

“…In [2], the same team studied the influence of cell-to-cell mismatch (channel doping, length, etc.) on the robustness.…”

“…They can be useful to identify hotspots in cells. Though, high computational cost makes it difficult to study numerous cells except in papers such as [2] where the method can be used to simulate local mismatches. s can be used to analyse the effects of die wire feet, and local irregularities (e.g.…”

“…As a matter of fact, it could be used to predict the robustness of a circuit and to help understand failure mechanisms such as critical temperatures and heating rates, current crowding, etc. [1], [2]. It could also be used for dieand packaging-design so as to optimise robustness, e.g.…”

“…SPICE) [5]- [7] or using a dedicated Finite Element (FE) software (e.g. Ansys) [2], [4], [8]- [10]. Although the first approach is a priori much faster, it is usually limited to a few thousands nodes (and often far less), leading to moderate accuracy.…”

Compact electro-thermal modeling of a SiC MOSFET power module under short-circuit conditions

“…Nevertheless, the reliability evaluation and fault-mode analysis, as well as the availability of compact physicsbased models, is still quite scarce for these modules, which in fact hinder their use in the design of power converters. The short circuit (SC) capability and robustness of discrete SiC MOSFETs have been extensively investigated [6]- [8] and modeled [9], while an assessment of the SC safe operating area for 1.2 kV modules is available in [10]. A number of compact behavioral and physical based models are available for discrete SiC MOSFETs and diodes [11], [12].…”