Experimental characterization of the damage induced to SiC power MOSFETs by heavy-ion irradiation is presented as a premise to a finite element simulation study aimed at gaining an insight into the physics of damage formation. Thanks to the new experimental setup, which is capable of accurately measuring the time evolution of the gate and drain leakage currents during irradiation, we herein demonstrate that the gate of a SiC power MOSFET is damaged by heavy-ion irradiation at biasing drain voltages lower than 100 V, which is less than 10% of the nominal blocking voltage of the tested devices. The evolution of the gate and drain leakage currents during irradiation is explained considering that localized resistive paths due to damage sites are formed across the gate oxide. The results presented herein indicate the strong sensitivity of SiC power MOSFETs to gate rupture even if the main concern in the literature addressed so far is the rupture of the drain structure due to single-event burnout.

A high-performance, high-voltage switch obtained by a series connection of 3300 V insulated gate bipolar transistor (IGBT) modules is presented. The correct voltage sharing between the devices is ensured by the presence of a simple and reliable auxiliary circuit, which acts as a feedback on the gate terminal. A comparison in terms of power losses, output currents, and switching performances to a single 6500 V IGBT module is also presented. An extended experimental analysis demonstrates strong advantages in terms of switching losses (up to 67%) and current and voltage gradients. Use of trench-gate IGBTs, available in the 3300 V size but not in the 6500 V one, allows extra performance to the series connection circuit, as experimental results show. Such circuit is suitable to increase performances of high-power, high-voltage inverters used in railway traction, in high-voltage energy distribution lines, and in high-power solid-state klystron modulators.

This article presents the results of a 2-D finite element simulation study of the gate damages induced by heavy-ion irradiation in SiC power metal-oxide-semiconductor field-effect transistors (MOSFETs). The time evolution of the electric field in the gate oxide is studied. Two effects are investigated: the first is associated with the charge deposition in the SiC portion of the MOSFET, with the time evolution studied using the 2-D finite element simulator; the second one results from holes generated during the ion transit, trapped in the gate oxide after the fast electrons have been quickly swept away by the electric field. Two different techniques have been combined for estimating the hole concentration in the gate oxide: the well-known recombination rate was modified to consider the trapped charge yield, as was recently done to better interpret single event gate rupture (SEGR) failure of silicon power MOSFETs. Under ion irradiation test conditions at which the gate damage experimentally starts to be observed, we demonstrate that, because of the ion impact, regardless of the ion linear energy transfer (LET), the peak value of the electric field in the gate oxide becomes practically equal to the oxide breakdown field (~12-15 MV/cm). Moreover, we show that simulations can be used to predict the test conditions at which gate damage starts to appear as a function of LET and the range of heavy ions used in the irradiation experiments.

A study is presented aimed at describing phenomena involved in Single Event Burnout induced by heavy ion irradiation in SiC Schottky diodes. On the basis of experimental data obtained for ⁷⁹Br irradiation at different energies, electro-thermal FEM is used to demonstrate that the failure is caused by a strong local increase of the semiconductor temperature. With respect to previous studies the temperature dependent thermal material properties were added. The critical ion energy calculated by this model is in agreement with literature experimental results. The substrate doping dependence of the SEE robustness was analyzed, proving the effectiveness of the developed model for device technological improvements.

In the last 15 years, the global demand for power saving, efficiency, and weight, size, and cost reduction in both the consumer and the industrial fields have strongly pushed the research and advancements in electronic power systems. Today, electronic power systems cover nearly the full voltage range (from volts to megavolts) and almost the full power range, if we exclude gigawatt-rated power plants. The applications include:smart grids . distributed power systems . photovoltaic (PV)/wind power stations . transportation (heavy/light traction, automotive, avionics, etc.) . industry applications (motor drives, arc welding, etc.) . consumer electronics (switch-mode power supplies, household appliances, etc.).