Role of nanopipes in degradation of AlGaN/InGaN/GaN devices operating at high voltage

摘要

We argue that the nanopipes recently observed in device-quality GaN grown on sapphire play an important role in degradation of nitride-based devices requiring high driving voltage, such as diode lasers or high-power electronics. The nanopipes offer a preferential path for the top (p-side) contact metal to migrate down towards the p-n junction under high-voltage operation, eventually causing a short and device failure. The metal migration process is enhanced by high voltage (tens of volts) required to drive high-current pulses through the device, and its elimination is of critical importance for achieving reliable GaN-based power devices and diode lasers.