Experimental heavy-ion responses of silicon carbide (SiC) junction barrier Schottky (JBS) diodes are presented. Measured data indicate that heavy ions having range less than the epitaxial thickness do not cause degradation or catastrophic failure, even with the device biased above the rated breakdown voltage. Measured data also indicate that when the heavy ions have range longer than the epitaxial layer thickness, the devices exhibit degradation as single-event leakage current (SELC), as well as catastrophic single-event burnout (SEB) at biases less than half of the rated breakdown voltage. Device failure was observed when irradiating with high-energy ions having long ranges, but not when irradiating with low-energy ions that stop in the epitaxial layer. Mechanisms of observed heavy-ion effects are examined with technology computer aided design (TCAD) device modeling.

Silicon carbide (SiC) power devices may exhibit step increases in leakage current when exposed to heavy ions while biased in the OFF state. Estimating the magnitude of this phenomenon over time in the variable solar energetic particle environment represents a challenge, as the probability of occurrence and step sizes are widely variable. The Prediction of Solar particle Yields for Characterizing Integrating Circuits (PSYCHIC) code is used to generate potential environmental flux spectra. Using an existing method, leakage current increases during broad-beam irradiation are characterized by frequency and magnitude. In this article, these characterizations are applied to various environmental flux spectra to generate a range of cumulative leakage current increases. This process is repeated to produce distributions of leakage current increases that account for environmental variability and step size variability. Comparing the results for various operating voltages, mission durations, and shielding, it is shown that shielding thickness and operating voltage have a significant influence on the potential cumulative leakage current increase.

A method of analyzing ion-induced reverse leakage current in SiC power devices is described. The resulting methodology enables the estimation of the proportion of ion strikes that produce step increases in leakage current as well as distributions of sensitive die areas relative to leakage step magnitude. These results are compared across various bias and ion linear energy transfer combinations to isolate the influence of each variable.

The onset of ion-induced reverse leakage current in SiC Schottky diodes is shown to depend on material properties, ion linear energy transfer (LET), and bias during irradiation, but not the voltage rating of the parts. This is demonstrated experimentally for devices from multiple manufacturers with voltage ratings from 600 to 1700 V. Using a device with a higher breakdown voltage than required in the application does not provide increased robustness related to leakage current degradation, compared to using a device with a lower voltage rating.

Ion-induced leakage current degradation, and single-event burnout may be manifestestations of the same device mechanisms in both silicon carbide power diodes and MOSFETs. In all cases there is a migration of the electrical field from the front body-drain interface to the back epi-drain n+ interface, with a peak exceeding the critical electric field of silicon carbide, causing avalanche generation which enables high short-duration power densities during an approximate 20 psec window after the ion strike. The degradation effect in JBS SiC diodes seems to be independent of the length of the epitaxial region for different voltage-rated diodes.

A two-photon absorption technique is used to understand the mechanisms of single-event effects (SEEs) in silicon carbide power metal-oxide-field-effect transistors (MOSFETs) and power junction barrier Schottky diodes. The MOSFETs and diodes have similar structures enabling the identification of effects associated specifically with the parasitic bipolar structure that is present in the MOSFETs, but not the diodes. The collected charge in the diodes varies only with laser depth, whereas it varies with depth and lateral position in the MOSFETs. Optical simulations demonstrate that the variations in collected charge observed are from the semiconductor device structure and not from metal/passivation-induced reflection. The difference in the spatial dependence of collected charge between the MOSFET and diode is explained by bipolar amplification of the charge carriers in the MOSFETs. Technology computer-aided design (TCAD) device simulations extend this analysis to heavy-ion-induced charge collection. In addition, there is discussion comparing this analysis with experimental results from prior works that show enhanced charge collection resulting from heavy-ion irradiation.

A two-photon absorption technique is explored for Silicon carbide power MOSFETs and power junction barrier Schottky diodes using a pulsed laser. The similarities in design between the specific MOSFETs and diodes tested permit using mechanisms existing in the different structures as explanation for observed current variation with laser position. The diode shows variation in average current with change in laser depth only, whereas the MOSFET shows variation both with shifts in depth and shifts in position across the striped geometry of the device. The variation is explained to be due to bipolar amplification of the charge carriers generated in the MOSFET when a pulse focus includes a channel below a gate. This conclusion is then reinforced using results from prior heavy ion and simulation work done for similar Silicon carbide MOSFETs.