Thermodynamic Studies of \b{eta}-Ga2O3 Nanomembrane Field-Effect Transistors on a Sapphire Substrate

摘要

The self-heating effect is a severe issue for high-power semiconductordevices, which degrades the electron mobility and saturation velocity, and alsoaffects the device reliability. On applying an ultrafast and high-resolutionthermoreflectance imaging technique, the direct self-heating effect and surfacetemperature increase phenomenon are observed on novel top-gate \b{eta}-Ga2O3 oninsulator field-effect transistors. Here, we demonstrate that by utilizing ahigher thermal conductivity sapphire substrate rather than a SiO2/Si substrate,the temperature rise above room temperature of \b{eta}-Ga2O3 on the insulatorfield-effect transistor can be reduced by a factor of 3 and thereby theself-heating effect is significantly reduced. Both thermoreflectancecharacterization and simulation verify that the thermal resistance on thesapphire 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 thesapphire substrate, which is 70% higher than that on the SiO2/Si substrate dueto reduced self-heating. Integration of \b{eta}-Ga2O3 channel on a higherthermal conductivity substrate opens a new route to address the low thermalconductivity issue of \b{eta}-Ga2O3 for power electronics applications.