Effect of H2O2 in passivation of n- and p-type 4H-SiC surfaces

Silicon carbide (SiC) presents many advantageous properties for electronic devices designed to work under extreme conditions such as high‐temperature (300–600 °C), high‐frequency, and high‐power. In addition, the formation of an insulating oxide layer (SiO2) by thermal oxidation is an attractive property for the microelectronics industry. Nevertheless, large densities of interface states (Dit) at the SiO2/SiC interface degrade electrical properties of the resulting structure. Such states are responsible for undesirable effects which hamper the development of SiC‐based devices. These electrically active defects are partially assigned to compounds named silicon oxycarbides (SiCxOy), that must be passivated. In this work, SiO2 was thermally grow on n‐ and p‐type 4H‐SiC using O2 flux bubbled on hot hydrogen peroxide (H2O2), which is a strong oxidizing agent, and acts in SiC surface converting SiCxOy in SiO2. Resulting structures were electrically characterized, and differences in Dit among n‐ and p‐type 4H‐SiC substrates were observed. To verify the H2O2 effects on SiC surface composition, oxidations of SiC using 18O as a marker were performed, followed by thermal treatment with H2O2. Samples underwent probing by nuclear reaction analysis and X‐ray photoelectron spectroscopy. Results shown a reduction in silicon oxycarbides induced by H2O2. Electrical and physico‐chemical data were related in order to explain differences among n‐ and p‐type samples.