Signal inversion and defect selectivity in charge pumping electrically detected magnetic resonance of a 4H-SiC n-channel metal-oxide-semiconductor field-effect transistor

Abstract

Charge pumping electrically detected magnetic resonance (CP-EDMR) has previously been demonstrated as a characterization technique for performance-limiting point defects in metal-oxide-semiconductor field-effect-transistors (MOSFETs). This Letter demonstrates the much-promised defect selectivity of CP-EDMR in a 4H-SiC n-channel MOSFET, differentiating between two distinct paramagnetic centers based on the kinetic properties, following from variation of the experimental CP parameters. The centers are shown to differ both in their characteristic g-shifts and in hyperfine interactions with surrounding nuclei. In addition, we show that under magnetic resonance conditions these two defects show opposite effects on the CP current, which results in a sign inversion of the CP-EDMR spectrum. For one defect, which only appears under relatively low-frequency CP-excitation, the microwaves induce a decrease in CP-current, while the other defect shows an increase at all applied CP-frequencies. Starting from an empirical CP model, we demonstrate that an enhanced efficiency of carrier capture or emission leads to either an increase or a decrease in the CP current, respectively. Simulations based on this model qualitatively reproduce the observed dependencies of the CP-EDMR signal on CP bias voltage and excitation frequency.