ISSN:
1089-7550
Source:
AIP Digital Archive
Topics:
Physics
Notes:
Recent studies related to the p-type doping of GaInAs epilayers, grown by molecular-beam epitaxy, mentioned erratic results concerning the electrical activity of beryllium (Be). This work reports on the secondary-ion mass spectrometry analysis of moderately Be-doped (between 5×1017 and 5×1018 cm−3 ) GaInAs/InP layers. Two of them were n type while they should have been p type. The comparison of Be depth profiles, obtained under either oxygen or cesium primary-ion bombardment, and detailed study of the secondary-ion mass spectra reveals that Be+ secondary-ion useful yields are largely enhanced in n-type samples when using cesium primary ions. Such behavior is attributed to the presence of varying oxygen contents in the samples, as confirmed by quantitative analyses. Comparison of Be and O concentrations indicates that the two elements probably form complexes inside the GaInAs matrix, providing a mechanism for the observed Be electrical inactivity. The use of positive secondary-ion yield enhancement under cesium bombardment is generalized to other elements (magnesium) in other semiconductor materials, in particular to the case of Au-Mn/GaAs ohmic contacts. Once again such ions reveal the presence of oxygen. Paradoxically, BeCs+ or MgCs+ molecular ions are not sensitive to the presence of oxygen. It is hypothesized that MCs+ species are more stable than MO+ . Such a differential effect is very helpful in characterizing the presence of oxygen in semiconductor materials.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.344278
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