ABSTRACT
ß-Ga2O3 is considered an attractive candidate for next-generation high-power electronics due to its large band gap of 4.9 eV and high breakdown electrical field of 8 MV/cm. However, the relatively low carrier concentration and low electron mobility in the ß-Ga2O3-based device limit its application. Herein, the high-quality ß-Ga2O3 single crystal with high doping concentration of â¼3.2 × 1019 cm-3 was realized using an optical float-zone method through Ta doping. In contrast to the SiO2/ß-Ga2O3 gate stack structure, we used hexagonal boron nitride as the gate insulator, which is sufficient to suppress the metal-insulator-semiconductor (MIS) interface defects of the ß-Ga2O3-based MIS field-effect transistors (FETs), exhibiting outstanding performances with a low specific on-resistance of â¼6.3 mΩ·cm2, a high current on/off ratio of â¼108, and a high mobility of â¼91.0 cm2/(V s). Our findings offer a unique perspective to fabricate high-performance ß-Ga2O3 FETs for next-generation high-power nanoelectronic applications.
ABSTRACT
For the first time, we report the successful fabrication of well-behaved field-effect transistors based on Nb-doped ß-Ga2O3 nanobelts mechanically exfoliated from bulk single crystals. The exfoliated ß-Ga2O3 nanobelts were transferred onto a purified surface of the 110 nm SiO2/Si substrate. These Nb-doped devices showed excellent electrical performance such as an ultrasmall cutoff current of â¼10 fA, a high current on/off ratio of >108, and a quite steep subthreshold swing (SS, â¼120 mV/decade). Furthermore, we investigated the temperature dependence down to 200 K, providing insightful information for its operation in a harsh environment. This work lays a foundation for wider application of Nb-doped ß-Ga2O3 in nano-electronics.