Residual thermal desorption studies of Ga adatoms on trenched Si(5512) surface

摘要

We present here the thermal stability studies of the room temperature adsorbed Ga/Si(5512) interfaces in the monolayer coverage regime, using AES and LEED as in-situ UHV characterization probes. Ga grows in Stranski-Krastanov growth mode at RT on the 2 × 1 reconstructed Si(5 512) surface where islands form on top of 2 ML of flat pseudomorphic Ga, yielding a (1 × 1) LEED pattern for coverages of 1.2 ML and above. When this RT adsorbed Ga/Si(5 512) interface is annealed at different temperatures, initially the strained Ga adlayers relax by agglomerating into 3D islands on top of a single Ga monolayer with an activation energy of 0.19 eV in the temperature range of 200-300 ℃ The remnant Ga monolayer with a sharp (1×1) LEED pattern desorbs at temperature >400 ℃, yielding the (11 2)-6 × 1 and 2 × (3 3 7) sub-monolayer superstructural. Finally at 720 ℃ Ga completely desorbs from the surface and leaves the clean 2×1 reconstructed Si(5512) surface. The studies demonstrate the richness of the atomically trenched high index Si(5512) surface, in obtaining several anisotropic features that can be used as templates to grow self-assembled nanostructures.