Thermodynamic Studies of ?-Ga₂O₃ Nanomembrane Field-Effect Transistors on a Sapphire Substrate.

ABSTRACT: The self-heating effect is a severe issue for high-power semiconductor devices, which degrades the electron mobility and saturation velocity, and also affects the device reliability. On applying an ultrafast and high-resolution thermoreflectance imaging technique, the direct self-heating effect and surface temperature increase phenomenon are observed on novel top-gate ?-Ga₂O₃ on insulator field-effect transistors. Here, we demonstrate that by utilizing a higher thermal conductivity sapphire substrate rather than a SiO₂/Si substrate, the temperature rise above room temperature of ?-Ga₂O₃ on the insulator field-effect transistor can be reduced by a factor of 3 and thereby the self-heating effect is significantly reduced. Both thermoreflectance characterization and simulation verify that the thermal resistance on the sapphire substrate is less than 1/3 of that on the SiO₂/Si substrate. Therefore, maximum drain current density of 535 mA/mm is achieved on the sapphire substrate, which is 70% higher than that on the SiO₂/Si substrate due to reduced self-heating. Integration of ?-Ga₂O₃ channel on a higher thermal conductivity substrate opens a new route to address the low thermal conductivity issue of ?-Ga₂O₃ for power electronics applications.

SUBMITTER: Zhou H 

PROVIDER: S-EPMC6645553 | biostudies-literature | 2017 Nov

REPOSITORIES: biostudies-literature