A transmission electron microscopy study was carried out on a series of AlGaN/GaN high-electron mobility transistor structures grown by plasma-assisted molecular beam epitaxy on Si(111). Threading dislocation behaviour and density were investigated for three heterostructures using an AlN/GaN superlattice and/or differently strained GaN layers. Threading dislocation densities were measured by transmission electron microscopy (at different depths) and high-resolution X-ray diffraction allowing one of the most complete studies so far performed; presenting separate values for edge, screw and mixed type threading dislocations.

Threading Dislocation Propagation in AlGaN/GaN Based HEMT Structures Grown on Si (111) by Plasma Assisted Molecular Beam Epitaxy. J.M.Mánuel, F.M.Morales, R.García, R.Aidam, L.Kirste, O.Ambacher: Journal of Crystal Growth, 2012, 357, 35-41