Effect of buffer layers and stacking faults on the reduction of threading dislocation density in GaN overlayers grown by metalorganic chemical vapor deposition
- 1 March 2001
- journal article
- research article
- Published by AIP Publishing in Journal of Applied Physics
- Vol. 89 (5), 2617-2621
- https://doi.org/10.1063/1.1344213
Abstract
We have studied the effect of the trimethylgallium (TMGa) flow rate in the GaN buffer layer on the optical and structural quality. From low temperature photoluminescencemeasurements, a GaN overlayer grown on a buffer layer with the TMGa flow rate of 80 μmol/min shows the intense donor-acceptor pair transition peak at 3.27 eV and the weak yellow band emission at 2.2 eV, which are related with stacking faults and threading dislocations from transmission electron microscopyimages, respectively. As the TMGa flow rate of the GaN buffer increases, the threading dislocation density rapidly decreased and stacking faults increased in the GaN overlayers. Also, a total threading dislocation density at the optimum condition of the buffer layer is the very low 1×10 8 cm −2 , which is due to the interaction of stacking faults with the vertical threading dislocations and the bending of threading dislocations near the stacking faults. High-resolution x-ray diffraction results show that a high density of stacking faults is correlated with the compressive strain of a GaN overlayer at the growth temperature.Keywords
This publication has 22 references indexed in Scilit:
- Superlattice-like stacking fault and phase separation of InxGa1−xN grown on sapphire substrate by metalorganic chemical vapor depositionApplied Physics Letters, 2000
- Influence of buffer layer and growth temperature on the properties of an undoped GaN layer grown on sapphire substrate by metalorganic chemical vapor depositionApplied Physics Letters, 2000
- The effect of Si doping on the defect structure of GaN/AlN/Si(111)Applied Physics Letters, 1999
- Dislocation generation in GaN heteroepitaxyJournal of Crystal Growth, 1998
- Gas source molecular beam epitaxy of wurtzite GaN on sapphire substrates using GaN buffer layersApplied Physics Letters, 1997
- Nucleation layer evolution in metal-organic chemical vapor deposition grown GaNApplied Physics Letters, 1996
- Influence of substrate-induced biaxial compressive stress on the optical properties of thin GaN filmsApplied Physics Letters, 1996
- Temperature dependence of interband transitions in GaN grown by metalorganic chemical vapor depositionApplied Physics Letters, 1995
- GaN Growth Using GaN Buffer LayerJapanese Journal of Applied Physics, 1991
- Effects of ain buffer layer on crystallographic structure and on electrical and optical properties of GaN and Ga1−AlN (0 < x ≦ 0.4) films grown on sapphire substrate by MOVPEJournal of Crystal Growth, 1989