In:
Journal of Applied Physics, AIP Publishing, Vol. 105, No. 4 ( 2009-02-15)
Abstract:
Thermal degradation of GaAs(001) surfaces has been studied using spectroscopic ellipsometry (SE), optical microscopy, ex situ atomic force microscopy (AFM), x-ray photoelectron spectroscopy (XPS), and photoluminescence (PL) techniques. The SE data suggest that thermal annealing causes no or little influence on the surface native oxide layer at temperatures T≤500 °C. Microscopic roughening starts to occur on GaAs surface at T & gt;500 °C, giving maximum AFM roughness (rms∼14 nm) at 540 °C, and then tends to smoothened at T & gt;540 °C (rms∼2.5 nm at 580 °C). Macroscopically roughened surfaces are observed at T & gt;500 °C, becoming more pronounced at higher annealing temperature. The Ga droplets are also observed at T≥600 °C that lead to catastrophically damaged surfaces and make SE measurement impossible. The XPS data indicate thinning of the native GaAs oxide in the limited temperature range 450 & lt;T & lt;580 °C; however, annealing at T≥580 °C leads to coverage with thermal oxides (Ga2O and As2O3). The naturally grown GaAs oxide is also found to act as a good passivation film against annealing-induced PL degradation.
Type of Medium:
Online Resource
ISSN:
0021-8979
,
1089-7550
Language:
English
Publisher:
AIP Publishing
Publication Date:
2009
detail.hit.zdb_id:
220641-9
detail.hit.zdb_id:
3112-4
detail.hit.zdb_id:
1476463-5
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