Improvement of Proton Radiation Hardness Using ALD-Deposited Al2O3 Gate Insulator in GaN-Based MIS-HEMTs

The proton radiation hardness has been investigated in GaN-based MIS-HEMTs with various gate insulating systems. Through the pulsed mode measurements and carrier mobility extraction, we have revealed that the Coulomb scattering generated by the trapped charges inside of the gate insulating layer is a key device performance degradation factor. We also have found out that SiN/Al 2 O 3 bi-layer gate insulating system exhibits stronger immunity to the proton radiation compared to the SiN single-layer gate insulating system since the dielectric layer quality of ALD deposited Al 2 O 3 is better than that of PECVD deposited SiN layer. Our systematic research emphasizes that to employ an excellent quality dielectric layer such as Al 2 O 3 is essential factor for the improvement of the proton radiation hardness in GaN-based MIS-HEMTs.