ON-Resistance of Ga2O3 Trench-MOS Schottky Barrier Diodes: Role of Sidewall Interface Trapping

We present a comprehensive study of the ON-resistance (R-ON) of Ga2O3 trench-MOS Schottky barrier diodes (SBDs), with a focus on the effect of sidewall interface trapping. Capacitance-voltage characteristics of MOS-capacitors and current-voltage characteristics of trench SBDs were all repeatedly measured under increasing forward-bias stress voltage to at least +15 V. Both reveal an increase in negative charges trapped near the MOS interface under increasing forward bias, as well as slow detrapping. The slow detrapping in trench SBDs causes a current collapse and a delayed turn-on behavior in the trench SBDs due to sidewall depletion. Through modeling of the fresh R-ON , we found that the sidewall depletion can be eliminated under sufficiently high forward bias. Interestingly, the dynamic R-ON under the forward-bias stress is lower than the fresh R-ON. Such an anomalous behavior is well-explained by analytical calculation of the apparent differential R-ON, which can be lowered by a modulation of fin-channel conductivity under forward bias. This study highlights the importance of sidewall interface quality in trench-MOS SBDs and calls for scrutiny on the interpretation of the apparent differential R-ON, as artificially low values may arise due to the voltage dependence of R-ON.

Automated summary

This study provides a comprehensive analysis of the ON-resistance (R-ON) of Ga2O3 trench-MOS Schottky barrier diodes, focusing on the impact of sidewall interface trapping. It was found that increasing forward bias leads to the accumulation of negative charges and slow detrapping near the MOS interface, causing current collapse and delayed turn-on behavior in trench SBDs. Interestingly, the dynamic R-ON under forward-bias stress is lower than the fresh R-ON, which can be attributed to modulation of fin-channel conductivity under forward bias.