Dynamic study of the surfaces of (001) gallium arsenide in metal-organic vapor-phase epitaxy during arsenic desorption

Citation
M. Pristovsek et al., Dynamic study of the surfaces of (001) gallium arsenide in metal-organic vapor-phase epitaxy during arsenic desorption, J APPL PHYS, 87(3), 2000, pp. 1245-1250
Citations number
20
Categorie Soggetti
Apllied Physucs/Condensed Matter/Materiales Science
Journal title
JOURNAL OF APPLIED PHYSICS
ISSN journal
00218979 → ACNP
Volume
87
Issue
3
Year of publication
2000
Pages
1245 - 1250
Database
ISI
SICI code
0021-8979(20000201)87:3<1245:DSOTSO>2.0.ZU;2-H
Abstract
We have investigated by reflectance anisotropy spectroscopy the arsenic des orption from GaAs (001) at various temperatures in metal-organic vapor-phas e epitaxy to obtain reaction orders and activation energies. The highest ar senic coverage, found at low temperatures with arsine stabilization, corres ponds to a (4 x 3) reconstruction. Without arsine, arsenic starts to desorb and less arsenic-rich reconstructions are observed, depending on temperatu re: c(4 x 4) (below 800 K), beta 2(2 x 4) (below 920 K), alpha(2 x 4), and only with hydrogen carrier gas finally (4 x 2) (above 950 K). Above 920 K t he reaction order differs in hydrogen and nitrogen atmosphere, probably due to an etching effect of hydrogen radicals. The five different desorption p rocesses show either a first- or zero-order time dependence. First order is related to the desorption from the terraces and zero order to desorption f rom the steps (or kinks) on the surfaces. The activation energies for all p rocesses are around 2.5 eV. This energy is, therefore, assumed to be the ac tivation energy for the removal of an arsenic dimer from the surface. (C) 2 000 American Institute of Physics. [S0021-8979(00)09203-3].