Development of gallium oxide power devices

Gallium oxide (Ga 2 O 3 ) is a strong contender for power electronic devices. The material possesses excellent properties such as a large bandgap of 4.7–4.9 eV for a high breakdown field of 8 MV cm −1 . Low cost, high volume production of large single‐crystal β‐Ga 2 O 3 substrates can be realized by melt‐growth methods commonly adopted in the industry. High‐quality n‐type Ga 2 O 3 epitaxial thin films with controllable carrier densities were obtained by ozone molecular beam epitaxy (MBE). We fabricated Ga 2 O 3 metal‐semiconductor field‐effect transistors (MESFETs) and Schottky barrier diodes (SBDs) from single‐crystal Ga 2 O 3 substrates and MBE‐grown epitaxial wafers. The MESFETs delivered excellent device performance including an off‐state breakdown voltage ( V br ) of over 250 V, a low leakage current of only few μA mm −1 , and a high drain current on/off ratio of about four orders of magnitude. The SBDs also showed good characteristics such as near‐unity ideality factors and high reverse V br . These results indicate that Ga 2 O 3 can potentially meet or even exceed the performance of Si and typical widegap semiconductors such as SiC or GaN for ultrahigh‐voltage power switching applications.