【Device Papers】Electro-thermal co-design of vertical β-Ga₂O₃ Schottky diodes with high-permittivity BaTiO₃ field-plate for high-field and thermal management

      Researchers from the Iowa State University have published a dissertation titled "Electro-thermal co-design of vertical β-Ga₂O₃ Schottky diodes with high-permittivity BaTiO₃ field-plate for high-field and thermal management" in APL Electronic Devices.

Abstract

      This work presents electrothermal co-design of vertical β-Ga₂O₃ Schottky barrier diodes (SBDs) to enhance both heat dissipation and high field management in high-power applications. Here, we demonstrate device-level thermal management tailored for two vertical β-Ga₂O₃ SBD structures that employed different edge termination techniques, such as field-plate and deep etch with sidewall field-plate, where the field-plate was formed with high-permittivity dielectric (BaTiO₃). The localized thermal hot spots were detected at the Schottky contact edges near the BaTiO₃ dielectric based field-plate. However, a substantial reduction of the thermal hotspots was observed by forming the field-plate with BaTiO₃ and a thermally conductive AlN insulator, where the AlN can effectively decrease Joule heating at the interface and the high permittivity of BaTiO₃ contributes to high field reduction. The deep etch and sidewall field-plate SBD structure further reduced accumulated heat and electric field near the critical anode edge by removing lateral depletion regions. We also analyzed thermal transport at dielectric/β-Ga₂O₃ interfaces using the Landauer approach, which revealed significantly higher thermal boundary conductance (TBC) enabled by AlN compared to BaTiO₃, attesting to the superior heat dissipation ability of the BaTiO₃/AlN field-plate compared to the BaTiO₃-only configuration. Experimental investigation with vertical metal/AlN/β-Ga₂O₃ diodes also extracted a high breakdown field (∼11 MV/cm) of AlN, significantly exceeding the material breakdown field of β-Ga₂O₃. This indicates that AlN can be an excellent choice for field-plate dielectric in vertical β-Ga₂O₃ SBDs to provide both enhanced high field sustainability and improved heat dissipation in high-power applications.

DOI：

https://doi.org/10.1063/5.0288035