Trap Analysis Based on Low-Frequency Noise for SiC Power MOSFETs Under Repetitive Short-Circuit Stress

Abstract

In this paper, the degradation behavior of the electrical characteristics was investigated, and trap analysis based on low-frequency noise (LFN) was carried out for the commercial 1.2-kV/30-A silicon carbide (SiC) power MOSFETs under repetitive short-circuit (SC) stress. The experiment results show that the on-state resistance (R dson) and threshold voltage (V th) increase significantly. Meanwhile, the drain-source current (I ds) decreases obviously with the increase of the SC cycles. Furthermore, the gatesource leakage current (I gss) of the SiC power MOSFETs increase greatly and the blocking characteristics deteriorated after 1000 SC cycles. The positive shift was observed on the gate-capacitance versus gatevoltage (C g-V g) curve, which shows that the damage region could be in channel along the SiC/SiO 2 interface after repetitive SC stress. In order to obtain the trap information, trap characterization was performed by using LFN method, and the LFN results show that the trap density increases with the SC cycles. The physical mechanism could be attributed to electrically active traps generated at SiC/SiO 2 interface and oxide layer due to the peak ionization rate, the perpendicular electrical field and high temperature during SC stress. The study may be useful to provide reference for converters design and fault protection of SiC power MOSFETs. INDEX TERMS Repetitive short-circuit (SC), low-frequency noise (LFN), traps, silicon carbide (SiC) power MOSFETs.

Development and Challenges of Reliability Modeling From Transistors to Circuits

“…The basis of studying the degradation mechanism is the analysis of the defect state inside the transistors, for which the most direct method is to measure the defect density generated by the degradation mechanism. Charge pumping and low-frequency noise 1/f measurements are widely used to evaluate the defects state [13]- [15]. Besides the study on the trap spatial distribution of high-k and ultra-thin oxide layer, charge pumping techniques based on the variation of the charge pumped with frequency and employed ring-oscillatorconnected devices are proposed in [16], [17].…”

Review of Methodologies for Evaluating Short-Circuit Robustness and Reliability of SiC Power MOSFETs

“…For instance, in Fig. 19 Another published method uses low-frequency noise (LFN) measurement for characterizing interfacial damages in the channel region of a SiC MOSFET under SC stress [109]. The method relies on the phenomenon that carbon vacancies clustering at the SiC/SiO2 interface is the most common defect responsible for the 1/f noise [110]- [112].…”

“…Because of that, it is possible to find an approximate value for the interface trap density from the LFN characteristics of the tested device [113]. However, the disadvantage of LFN measurement is that the type of injected charges cannot be distinguished [109].…”

Review of Health Prognostics and Condition Monitoring of Electronic Components

“…All the designers and users assume that failures are random and ascendable so that failure rate-based technique can be imposed. The silicon carbide power MOSFET is analyzed under short circuit stress, and its degradation behaviour is explored using trap analysis [28] It is further understood that design does not dominate any of the failure modes of the circuit. Otherwise, the manufacturers and designers need to explore advanced methods to locate a more critical failure mechanism.…”