Impact of temperature and switching rate on forward and reverse conduction of GaN and SiC cascode devices:A technology evaluation

This paper provides the first comprehensive study on the forward and reverse conduction and reliability performance of the Gallium Nitride (GaN) and Silicon Carbide (SiC) power cascode devices, in comparison with standard silicon & SiC power MOSFETs and the silicon superjunction MOSFETs. The impact of temperature and the external gate resistance are investigated, and a practical yet accurate analytical model has been developed to calculate the switching rate of cascode devices. The 3 rd quadrant operation devices through the body diodes is also studied along with unclamped switching properties for avalanche breakdown limits of GaN and SiC cascodes

Unclamped inductive stressing of GaN and SiC Cascode power devices to failure at elevated temperatures

In this paper, the ruggedness performance of GaN HEMT and SiC JFET devices in cascode configuration with a low voltage silicon power MOSFET has been evaluated experimentally. The impact of the bus voltage on the drain current and avalanche energy are investigated as well as the temperature sweep to enable analysis of the alternation of these parameters on the Unclamped Inductive Switching (UIS) ruggedness of cascode devices. The experimental measurements show that the GaN cascode devices have lower avalanche energy rating when compared with the closely rated SiC cascode devices just before the failure. SiC cascode devices can also withstand higher bus voltage in comparison to GaN cascode devices when under electrothermal stress by unclamped inductive switching. The analysis of transfer characteristics and leakage current of SiC JFET & GaN HEMT cascode structures following UIS stress have also been performed together with Computed Tomography (CT) Scan imaging to determine the per-area avalanche energy density

A New and Simple Approach for Decontamination of Food Contact Surfaces with Gliding Arc Discharge Atmospheric Non-Thermal Plasma

In this study, a gliding arc discharge (GAD) microplasma system was designed, and its decontamination effect was investigated on stainless steel (SS), silicone (Si), and polyethylene terephthalate (PET) surfaces artificially contaminated with 8.15 +/- 0.28 log cfu/mL of Escherichia coli and 6.18 +/- 0.21 log cfu/mL of Staphylococcus epidermidis. Each of the contaminated surfaces was treated with high purity air (79% nitrogen and 21% oxygen) or nitrogen plasmas for 1-10 min at varying rates of gas flow. Significant reductions of 3.76 +/- 0.28, 3.19 +/- 0.31, and 2.95 +/- 0.94 log cfu/mL in S. epidermidis, and 2.72 +/- 0.82, 4.43 +/- 0.14, and 3.18 +/- 0.96 log cfu/mL in E. coli on SS, Si, and PET surfaces, respectively, were achieved after 5 min of plasma treatment by using nitrogen as the plasma forming gas (p < 0.05). The temperature changes of each surface during plasma generation were lower than 35 degrees C and were not affected by the type of plasma forming gas. Additionally, morphological changes in the structure of E. coli and S. epidermidis after GAD plasma treatments were demonstrated using scanning electron microscopy (SEM)

Analysis of cyclic spontaneous switchings in GaN & SiC cascodes by snappy turn-off currents

This paper investigates the crosstalk-induced spontaneous switchings as continuous cycles of turn-on and turn-off transients as a key reliability criterion in SiC and GaN cascode power devices. The paper presents a wide range of measurements to describe the severity of unwanted switching cycles in presence of a few diodes with high turn-off dI/dt which results in a negative gate voltage induced by the source inductance. Modelling is performed which confirms the theory described to explain the root cause of the continued oscillatory transients and comparisons are made with standalone SiC power MOSFETs