Temperature-Dependent Short-Circuit Capability of Silicon Carbide Power MOSFETs

Abstract

This paper presents a comprehensive short circuit ruggedness evaluation and numerical investigation of up-to-date commercial silicon carbide (SiC) MOSFETs. The short circuit capability of three types of commercial 1200 V SiC MOSFETs is tested under various conditions, with case temperatures from 25 o C to 200 o C and DC bus voltages from 400 V to 750 V. It is found that the commercial SiC MOSFETs can withstand short circuit current for only several microseconds with a DC bus voltage of 750 V and case temperature of 200 o C. The experimental short circuit behaviors are compared and analyzed through numerical thermal dynamic simulation. Specifically, an electro-thermal model is built to estimate the device internal temperature distribution, considering the temperature dependent thermal properties of SiC material. Based on the temperature information, a leakage current model is derived to calculate the main leakage current components (i.e. thermal, diffusion, and avalanche generation currents). Numerical results show that the short circuit failure mechanisms of SiC MOSFETs can be thermal generation current induced thermal runaway or high temperature related gate oxide damage.

A Structural Based Thermal Model Description for Vertical SiC Power MOSFETs under Fault Conditions

“…From both diagrams in Figure 5, one can see that IGBT model A is delivering the lowest and model C is delivering a value which is unrealistically high. Model B in Figure 5(b) shows that the critical temperature ,crit at failure is around 800 ∘ C, which is in line with numerical calculations on the SC capability of SiC MOSFETs in [3].…”

“…In the literature, some values of crit at specific boundary conditions can also be found in [2][3][4][5][6][7][8] with devices of the same chip generations and manufacturer. They are in accordance with the displayed results in this article but often there is only one value of crit at completely different operating points or without concrete testing conditions given.…”

“…At the same time, reliability of these devices under harsh operating conditions is still an issue [2][3][4][5][6][7][8]. One of its most important issues is the short-circuit (SC) robustness against single or repetitive faults events and overcurrent conditions.…”

Comparative evaluation of the short-circuit withstand capability of 1.2kV silicon carbide (SiC) power transistors in real life applications

“…Note that the ΔT OFF = 10 μs N 3.3 μs. It is, thus, evident that the gate and source terminals are shorted due to the extensive thermal stress, as also observed by authors of [25]. v GS is slightly decreasing before destruction due to leakage currents flowing through the gate oxide.…”

A Comprehensive Study of Short-Circuit Ruggedness of Silicon Carbide Power MOSFETs

“…62 The device temperature was also estimated to be very high, 63 leading to melting of aluminum and finally to device failure. 64 Wide experimental data on different commercial devices and 65 numerical investigations through electrically and thermally 66 coupled models were exploited to analyze the temperature 67 dependence of SC withstanding capability in [21]. In [22], 68 electrothermal simulations are shown to analyze the SC SOA 69 using compact models.…”