Epitaxial lateral overgrowth of GaN using high-dose N⁺-ion- implantation

Epitaxial lateral overgrowth (ELO) process has limited use in GaN devices due to the uneasiness of regrowth or the likeliness of contamination from the ELO mask, even though it is a method to reduce the dislocation density in GaN grown on sapphire substrate. Here we introduce a maskless and single-step ELO process using a high-dose N⁺-ion implantation. We employed a high-dose N⁺-ion implantation as an ELO mask instead of usual dielectric material such as Si_xN_y or SiO₂. The GaN layer was laterally grown over the ion implanted array formed in a stripe pattern of 4-μm-width, resulting in a complete coalescence after 30 min. TEM and photoluminescence analysis confirmed the reduced dislocation density of the ELO grown GaN layer.