High-density plasma-induced etch damage of InGaN/GaN multiple quantum well light-emitting diodes

Plasma-induced damage of InGaN/GaN multiple quantum well (MQW) light-emitting diodes (LEDs) has been studied in terms of forward turn-on and reverse breakdown voltages, together with etch rate and surface morphology. The physical degradation of sidewall along with rough surface morphology of n–GaN caused by increased ion scattering induced the deterioration of the forward and reverse voltages. The forward turn-on voltage was relatively independent of the pressure up to 20 mTorr. The reverse breakdown voltage showed the worst degradation at 75% ${\mathrm{Cl}}_2$ mainly because of a sidewall contamination. It was found that the turn-on voltage is sensitive to the surface roughness of the etched n–GaN and the breakdown voltage is strongly affected by the sidewall contamination. Annealing under nitrogen after the mesa etching improved the electrical properties of the InGaN/GaN MQW LEDs.