Low Threshold Voltage Shift in AlGaN/GaN MIS-HEMTs on Si Substrate Using SiNx/SiON as Composite Gate Dielectric

This study has demonstrated AlGaN/GaN metal-insulator-semiconductor high electron mobility transistors (MIS-HEMTs) on Si substrates with a SiNx/SiON composite gate dielectric. The threshold voltage shift in the devices was investigated. MIS-HEMTs dielectric exhibited superior uniformity and small hysteresis than reference device SiNx only variation of mainly related to trapping process by interface states, as confirmed band diagrams at different biases. Based frequency-dependent capacitance measurements, state densities single dielectrics were extracted, where former showed much smaller density. These results indicate that can effectively improve performance GaN-based contribute development high-performance GaN electronic devices.