500 °C operation of β-Ga2O3 field-effect transistors

Abstract

We demonstrated 500 °C operation of field-effect transistors made using ultra-wide bandgap semiconductor β-Ga2O3. Metal–semiconductor field-effect transistors were fabricated using epitaxial conductive films grown on an insulating β-Ga2O3 substrate, TiW refractory metal gates, and Si-implanted source/drain contacts. Devices were characterized in DC mode at different temperatures up to 500 °C in vacuum. These variable-temperature measurements showed a reduction in gate modulation of the drain current due to an increase in gate leakage across the gate/semiconductor Schottky barrier. Devices exhibited a reduction in transconductance with increasing temperature; despite this, drain current increased with temperature due to a reduction in threshold voltage caused by the de-trapping of electrons from deep-level traps. Devices also showed negligible change in semiconductor epitaxy and source/drain contacts, hence demonstrated recovery to their room-temperature electrical properties after the devices were tested intermittently at different high temperatures in vacuum. The mechanism of gate leakage was also explored, which implicated the presence of different conduction mechanisms at different temperatures and gate electric fields.

Temperature dependence of electrical characteristics of Si-implanted AlN layers on sapphire substrates

“…Figure 5(b) benchmarks the trade-off between on-off ratio and the measurement temperature of our AlN MESFET and other FETs in the literature. 1,8,21,58,59) Our transistor has already showed good high-temperature performance in comparison with GaN, β-Ga 2 O 3 , and diamond FETs. Despite smaller E g , the SiC JFET shows excellent high-temperature performance.…”

“…Moreover, SBDs and metal-semiconductor field-effect transistors (MESFETs) fabricated from Ga 2 O 3 and diamond are subject to contact degradation at high temperature. [6][7][8] By contrast, AlN is more attractive than these materials for high-temperature applications because of its high E g of 6.1 eV and controllable p-and n-type doping.…”