DC and pulsed IV characterisation of AlGaN/GaN MOS-HEMT structures with Al2O3 gate dielectric prepared by various techniques

AlGaN/GaN metal-oxide-semiconductor high electron mobility transistors (MOS-HEMTs) represent an important technology for future high-efficient power and RF electronics. Due to oxide/semiconductor interface issues, fabrication of reliable MOS gate stack is still challenging, however. In this work we investigated the influence of gate oxide preparation technique to static and pulsed-mode operation of Al₂O₃/GaN/AlGaN/GaN MOS-HEMTs. Devices with gate oxide prepared by high-temperature MOCVD and low-temperature ALD using water vapour or ozone as oxidants are compared in terms of dynamic on-state resistance (R_DSon), threshold voltage shift (ΔV_th), and Al₂O₃/GaN interface charge density (N_it).