Controlling dislocation clusters in selective area growth of gallium nitride with hexagonal configurations of serpentine channel mask

Abstract

The periodic distribution of threading dislocations (TDs) originating from the windows and coalescence areas during epitaxial lateral overgrowth (ELOG) of GaN hindered the further development of large wafer-scale crystal growth. Although, the serpentine channel patterned sapphire substrate (SCPSS) effectively controlled TDs from the window areas, however, the periodic distribution of TDs from coalescence areas was still problematic. To control the periodicity of TDs from coalescence areas, selective area growth (SAG) was introduced in the form of a triangular pattern. However, these selective patterns were relaxed and clusters of TDs were gliding. Despite adding InGaN-Interlayer, the complete elimination of TD clusters was still a great challengeTherefore, the hexagonal configuration of the SCPSS was proposed. Characterization results proved that the hexagonal configuration of SAG assisted by facet structures effectively controls TDs clusters in the SAG. In addition, defects from the meeting fronts were also effectively controlled through the convergence of the growth fronts merging from hexagonal sides at central single-dimensionless points. Optimizing high-quality growth by the hexagonal configuration of SCPSS is promising for GaN-based devices such as laser diodes (LDs) and light-emitting diodes (LEDs).