The addition of bursts of Si was observed to correlate with the reduction of threading screw dislocations during epitaxial growth of GaN on Si by metalorganic chemical vapor deposition. The reduction was associated with bending of screw dislocations and so-called pairing with equivalent neighboring dislocations having opposite Burgers vectors. This resulted in the formation of square dislocation loops. When the correct type of dislocation was not available, the dislocation continued to propagate in the original direction, leaving behind a kink at the Si-rich position. These observations applied only to dislocations with a screw component. Edge dislocations were not affected by Si delta-doping. A mechanism for the termination of threading screw dislocation was proposed which involved pinning by the Si impurities of the surface lattice steps associated with screw dislocations.

Dislocation Annihilation by Silicon Delta-Doping in GaN Epitaxy on Si. O.Contreras, F.A.Ponce, J.Christen, A.Dadgar, A.Krost: Applied Physics Letters, 2002, 81[25], 4712-4