SWELLING OF GASB AT LOW ENERGIES (1.3-14.5 KEV)

The III-V compound gallium antimonide (GaSb), which has a relatively n arrow band gap, is of increasing importance for the fabrication of opt oelectronic devices. However, the material was shown to swell during h igh energy ion implantation or under low energy cesium bombardment use d for secondary ion mass spectrometry (SIMS), at 14.5 keV. Here, the p henomenon has been investigated under cesium and oxygen bombardment, b etween 1.25 and 14.5 keV, with doses from 10(15) cm-2 to above 10(17) cm-2. The swelling occurred independently of the nature of primary ion s and the mechanism is related to the damage caused by the primary ion bombardment rather than to the presence of oxygen, as previously prop osed. In the case of SIMS, both swelling and sputtering occur simultan eously; preferential sputtering reveals microcrystals whose dimensions depend on both the thicknesses of damaged layers, hence the penetrati on depths of primary ions, and the beam impact angles. The phenomenon has two major influences on SIMS measurements in (AlGa)Sb structures: it deteriorates the depth resolution and it modifies the elemental ion yields above certain doses.