Reduction mechanisms for dislocation densities in GaN heteroepitaxy over Si substrate patterned with a serpentine channel structure

Heteroepitaxial growth of gallium nitride (GaN) over patterned Silicon (Si) substrates using serpentine channel structure was demonstrated and studied with transmission electron microscopy (TEM). Cross-sectional TEM images showed that the dislocations were filtered out effectively, through two 90 degrees turns in GaN growth front with the unique serpentine channel structure, resulting in high crystal quality GaN materials over the top mask layer. Dislocation behaviours at different parts of the structure were investigated to understand the mechanism of dislocation density reduction.