The influence of a thin porous SiNx interlayer on the growth of GaN by metalorganic chemical vapor deposition was studied. The interlayer was deposited on a GaN template by introducing silane in the presence of ammonia into the metalorganic chemical vapor deposition chamber, and a GaN overlayer was deposited on the interlayer. The SiNx interlayer produces inhomogeneous nucleation and lateral growth of the overlayer, causing bending of dislocations towards facet walls, and it also blocks some dislocations from entering the overlayer. The dislocation density for a GaN overlayer grown on a SiNx interlayer was reduced to 7 x 108/cm2, which was an order of magnitude less than that for a control sample grown without an interlayer.

Dislocation Density Reduction in GaN using Porous SiN Interlayers. A.Sagar, R.M.Feenstra, C.K.Inoki, T.S.Kuan, Y.Fu, Y.T.Moon, F.Yun, H.Morkoç: Physica Status Solidi A, 2005, 202[5], 722-6