Current transport mechanism of lateral Schottky barrier diodes on -Ga₂O₃/SiC structure with atomic level interface

Heterogeneous integration of beta-Ga2O3 on highly thermal conductive SiC substrate by the ion-cutting technique is an effective solution to break the heat-dissipation bottleneck of beta-Ga2O3 power electronics. In order to acquire high-quality beta-Ga2O3 materials on SiC substrates, it is essential to understand the influence of the ion-cutting process on the current transport in beta-Ga2O3 devices and to further optimize the electrical characteristics of the exfoliated beta-Ga2O3 materials. In this work, the high quality of beta-Ga2O3/SiC structure was constructed by the ion-cutting process, in which an amorphous layer of only 1.2 nm was formed between beta-Ga2O3 and SiC. The current transport characteristics of Au/Pt/Ni/beta-Ga2O3 Schottky barrier diodes (SBDs) on SiC were systematically investigated. beta-Ga2O3 SBDs with a high rectification ratio of 10(8) were realized on a heterogeneous beta-Ga2O3 on-SiC (GaOSiC) substrate. The net carrier concentration of the beta-Ga2O3 thin film for GaOSiC substrate was down to about 8% leading to a significantly higher resistivity, compared to the beta-Ga2O3 donor wafer, which is attributed to the increase in acceptor-type implantation defects during the ion-cutting process. Furthermore, temperature-dependent current-voltage characteristics suggested that the reverse leakage current was limited by the thermionic emission at a low electric field, while at a high electric field, it was dominated by the Poole-Frenkel emission from E3 deep donors caused by the implantation-induced Ga-O antisite defects. These results would advance the development of beta-Ga2O3 power devices on high thermal conductivity substrate fabricated by ion-cutting technique.