P‐Type Electrical Activation in GaN by Mg Ion Implantation for PN Junctions

The p‐type of electrical activation via Mg implantation into GaN containing a trace of indium (1.54%) was demonstrated. Implantation was performed at room temperature, followed by post‐implantation annealing at 1230°C under atmospheric pressure. The improved activation efficiency at a lower annealing temperature of 1230°C (compared to 1400°C applied by multicycle rapid thermal annealing and ultra‐high pressure annealing was attributed to the lower bond formation energy of In–N (7.695 eV) compared to Ga–N (9.265 eV), suggesting Mg ions at interstitial sites preferentially replace In rather than Ga. Moreover, low‐rate dry etching and Tetramethylammonium Hydroxide (TMAH) treatment were applied to effectively remove the surface damages induced by ion implantation and high‐temperature annealing, resulting in a significant current switching ratio enhancement of ~ 10 ⁵ . Comparison of the electroluminescence spectra between Mg‐implanted and nonimplanted samples under identical conditions clearly confirmed effective electrical activation of Mg in In _1.54% Ga _98.46% N.