ON-State Degradation in AlGaN/GaN-on-Silicon Schottky Barrier Diodes: Investigation of the Geometry Dependence

In this paper, we present the results of a combined measurement/simulation analysis of the degradation induced by on-state stress in Au-free AlGaN/gallium-nitride-on-Si Schottky barrier diodes (SBDs). Turn-on voltage (V
_TON
) and on-resistance (R
_ON
) are affected by charge carrier trapping/detrapping, occurring in different regions and caused by different mechanisms, when a high stress current is applied to the device. In particular, we have investigated the degradation of SBDs adopting different stress conditions and analyzing the influence of the diode geometry; consequently, we were able to identify the physical mechanisms responsible for long-term degradation of V
_TON
and R
_ON
. In addition, thanks to this approach, a critical electric field for the R
_ON
degradation has been determined.