A mini-ALE attachment to UHV surface analysis equipment

An atomic layer epitaxy (ALE) module has been developed that can be attached to a port of UHV surface analysis equipment. In our case this would, for instance, enable analysis by low energy ion scattering (LEIS), X-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM). This so-called mini-ALE will be used to study and optimize the growth mechanisms of mono-atomic and sub-monatomic metal layers and to prepare model samples for studies of catalysts and small metal clusters. The mini-ALE basically consists of a small (≈ 1 cm3) growth chamber suspended in an UHV environment, with valved inlets for the reaction and purge gases. The sample can be transferred to the analysis chamber via a load-lock. The surface temperature of the sample can be controlled from room temperature to approximately 500°C. The system was tested by attaching it to one of our LEIS set-ups and growing CuO on Al2O3, using Cu(acac)2 and artificial air as reactants. Cu growth was observed, covering about 3% of the surface. Results on growth as a function of surface temperature are given.