Diffusion of Mn in gallium arsenide.
|Rafał Jakieła 2,3, Adam Barcz 1,3, Elżbieta Wegner 2, Andrzej Zagojski 2|
1. Institute of Electron Technology (ITE), al. Lotników 32/46, Warszawa 02-668, Poland
The aim of this work is to compare carrier concentration, diffusion coefficient and shape of the manganese atomic profile in GaAs layers treated under different annealing conditions. Diffusion was performed from implanted Mn as well as from external source of Mn. Manganese implanted GaAs, GaAs:Zn and GaAs:Te bulk samples were investigated. Implantation was performed at room temperature to a dose of 1016/cm2 at an energy of 100 keV. The samples, protected with AlN layers, were annealed at 800OC and 900OC with RTA (rapid thermal annealing) method as well as at 900OC and 1000OC in sealed quartz ampoule.
After removing the AlN films the extent of diffusion of the implanted species was characterized using the SIMS (Secondary Ion Mass Spectrometry) technique.
The depth profiles of in-diffused manganese strongly indicate that the diffusion coefficient D is concentration-dependent. In case of quartz ampoule annealing of implanted samples the Mn diffusivity was found larger when GaAs was annealed with arsenic overpressure combined with the AlN cap than that annealed without cap. Over ten times shallower diffusion range in uncovered sample then that in covered with AlN is interpreted in terms of generation of additional vacancies in the Ga sub-lattice. Mn atoms incorporate in Ga sites lowering diffusion coefficient. In case of diffusion from external source into differently doped GaAs, the largest diffusion coefficient was found for GaAs:Zn. This result indicates highest Mn diffusivity in sample with low Fermi level, which provides lowest Ga vacancies concentration. Both results confirm an interstitial diffusion mechanism.
The Boltzmann-Matano analysis was employed to evaluate the concentration–dependent diffusion coefficient of Mn in GaAs.
Presentation: poster at E-MRS Fall Meeting 2005, Symposium B, by Rafał Jakieła
See On-line Journal of E-MRS Fall Meeting 2005
Submitted: 2005-05-31 07:24 Revised: 2009-06-07 00:44