Molecular beam epitaxy of free-standing wurtzite AlxGa1−xN layers.
- Resource Type
- Article
- Authors
- Novikov, S.V.; Staddon, C.R.; Martin, R.W.; Kent, A.J.; Foxon, C.T.
- Source
- Journal of Crystal Growth. Sep2015, Vol. 425, p125-128. 4p.
- Subject
- *MOLECULAR beam epitaxy
*WURTZITE
*GROUP 13 elements
*NITRIDES
*X-ray microanalysis
- Language
- ISSN
- 0022-0248
Recent developments with group III nitrides present Al x Ga 1− x N based LEDs as realistic devices for new alternative deep ultra-violet light sources. Because there is a significant difference in the lattice parameters of GaN and AlN, Al x Ga 1− x N substrates would be preferable to either GaN or AlN for ultraviolet device applications. We have studied the growth of free-standing wurtzite Al x Ga 1− x N bulk crystals by plasma-assisted molecular beam epitaxy (PA-MBE). Thick wurtzite Al x Ga 1− x N films were grown by PA-MBE on 2-in. GaAs (111)B substrates and were removed from the GaAs substrate after growth to provide free standing Al x Ga 1− x N samples. X-ray microanalysis measurements confirm that the AlN fraction is uniform across the wafer and mass spectroscopy measurements show that the composition is also uniform in depth. We have demonstrated that free-standing wurtzite Al x Ga 1− x N wafers can be achieved by PA-MBE for a wide range of AlN fractions. In order to develop a commercially viable process for the growth of wurtzite Al x Ga 1− x N substrates, we have used a novel Riber plasma source and have demonstrated growth rates of GaN up to 1.8 µm/h on 2-in. diameter GaAs and sapphire wafers. [ABSTRACT FROM AUTHOR]