ISSN:
1089-7550
Source:
AIP Digital Archive
Topics:
Physics
Notes:
The III-V compound gallium antimonide (GaSb), which has a relatively narrow band gap, is of increasing importance for the fabrication of optoelectronic devices. However, GaSb was shown to swell during high energy ion implantation. The surface upheaval increased with the dose, energy, and mass of implanted ions, reaching heights of about 1 μm under the most harmful conditions. With the low energies used for secondary ion mass spectrometry (SIMS), i.e., between 1 and 20 keV, a similar behavior was observed under cesium bombardment, with elevations of 100 nm, giving rise to abnormal secondary ion yields and depth profile distortions. Here, the phenomenon has been investigated under cesium and oxygen bombardment, between 1.25 and 14.5 keV, with doses from 1015 cm−2 to above 1017 cm−2. The swelling of the material is confirmed whatever the nature of primary ions. The mechanism is related to the damage caused by the primary ion bombardment rather than to the presence of oxygen. The critical damage threshold of 1022 cm−3 atom displacements is largely exceeded, resulting in vacancy clusters, microtwins, and finally inducing polycrystallization of GaSb with an upheaval of the initial surface. In the case of SIMS, both swelling and sputtering occur simultaneously. Preferential sputtering reveals microcrystals whose dimensions depend on both the thicknesses of damaged layers, and hence, the penetration depths of primary ions and the beam impact angles. The phenomenon has two major consequences on SIMS measurements in (AlGa)Sb structures. First, it deteriorates the depth resolution, and second, it modifies the elemental secondary ion yields above a certain dose. Both these problems are addressed and a comparison with (AlGa)As is made.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.353150
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