Isolation properties and failure mechanisms of vertical Pt/n-GaN SBDs

This paper reports on the isolation properties and failure mechanism of n-type vertical Pt / n-GaN Schottky barrier diodes and the dependence on the drift layer doping concentration. The results indicate that (i) inde-pendently on doping density, the Schottky barrier height is lower than the theoretical expectation, and this limits the blocking properties of the junction; (ii) barrier lowering was associated to an injection mechanism that in-volves deep levels in the semiconductor layer, near the junction, favouring injection and tunneling of carriers. By performing a detailed analysis of the breakdown mechanism, we also demonstrated that (iii) the failure of the devices in reverse bias condition is related to a power-related mechanism associated to current flowing along the mesa edges. We thus conclude that (iv) a good edge termination and passivation of the surfaces is fundamental to exploit the full blocking capability of the semiconductor.

Automated summary

This paper reports on the isolation properties and failure mechanism of n-type vertical Pt / n-GaN Schottky barrier diodes and the dependence on the drift layer doping concentration. The results indicate that the Schottky barrier height is lower than expected, regardless of the doping density, limiting the blocking properties of the junction. The barrier lowering is associated with an injection mechanism involving deep levels in the semiconductor layer near the junction, facilitating carrier injection and tunneling. Furthermore, the failure of the devices in reverse bias condition is attributed to a power-related mechanism associated with current flowing along the mesa edges. Therefore, a good edge termination and passivation of the surfaces are essential for fully exploiting the blocking capability of the semiconductor.