Abstract
The device performance deterioration mechanism caused by the total ionizing dose effect after the γ-ray irradiation was investigated in GaN-based metal-insulator-semiconductor high electron mobility transistors (MIS-HEMTs) for a 5 nm-thick SiN and HfO2 gate dielectric layer. The γ-ray radiation hardness according to the gate dielectric layer was also compared between the two different GaN-based MIS-HEMTs. Although HfO2 has exhibited strong tolerance to the total ionizing dose effect in Si-based devices, there is no detail report of the γ-ray radiation effects in GaN-based MIS-HEMTs employing a HfO2 gate dielectric layer. The pulsed-mode stress measurement results and carrier mobility behavior revealed that the device properties not only have direct current (DC) characteristics, but radio frequency (RF) performance has also been mostly degraded by the deterioration of the gate dielectric quality and the trapped charges inside the gate insulator. We also figured out that the immunity to the γ-ray radiation was improved when HfO2 was employed instead of SiN as a gate dielectric layer due to its stronger endurance to the γ-ray irradiation. Our results highlight that the application of a gate insulator that shows superior immunity to the γ-ray irradiation is a crucial factor for the improvement of the total ionizing dose effect in GaN-based MIS-HEMTs.
Highlights
Gallium nitride based high electron mobility transistors (HEMTs) have been intensively studied for high frequency, high power, low noise, and aerospace applications thanks to its wide bandgap, high breakdown electric field, high carrier density, and high carrier mobility at the hetero-interface [1,2]
We focused on the total ionizing dose (TID) effects in GaN-based MIS-HEMTs for a 5 nm-thick HfO2 gate dielectric layer for the minimization of the transconductance and radio frequency (RF) performance degradation
The device performance degradation mechanism of the GaN-based MIS-HEMTs induced by the γ-ray radiation was investigated through electrical device characterization, which was total ionizing dose effect generated at a great part of the gate insulator rather than the AlGaN barrier and GaN layers
Summary
Gallium nitride based high electron mobility transistors (HEMTs) have been intensively studied for high frequency, high power, low noise, and aerospace applications thanks to its wide bandgap, high breakdown electric field, high carrier density, and high carrier mobility at the hetero-interface [1,2]. The radiation hardness of the gate insulator is weaker than that of AlGaN and GaN in GaN-based MIS-HEMTs. The degradation of the dielectric quality and trapped charges inside the dielectric layer (and/or at the dielectric interface), which is the total ionizing dose (TID) effects generated by the radiation, deteriorate direct current (DC) and RF performance of the devices. It is necessary to investigate the TID effects induced by γ-ray irradiation on the device characteristics in GaN-based MIS-HEMTs, since this results in the degradation of the dielectric layer quality rather than AlGaN and GaN [24]. In comparison with the SiN gate dielectric layer, when HfO2 was employed, the threshold voltage (VTH) shift (∆VTH), transconductance (gm) maximum deterioration (∆gm,max), drain current (ID), and reduction (∆ID) were improved from 0.15 to 0.075 V, 5.42 to 2.27%, and 5.40 to 2.31%, respectively. Our systematic measurements revealed that the HfO2 gate insulator showed excellent immunity to the γ-ray radiation and is suitable for aerospace electronics compared to the SiN dielectric layer
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
