Ge epitaxial island growth on a graphitized C-rich 4H-SiC(0001) surface

Abstract: Epitaxial Ge islands on a SiC(0001) substrate have been examined by reflection high-energy electron diffraction (RHEED). These islands have been obtained by depositing three monolayers of Ge at 500°C on a graphitized SiC (6√3×6√3)R30° reconstructed surface. This surface has been chosen for its ability to support epitaxial Ge island growth in a Volmer-Weber mode. The RHEED technique has allowed us to determine the epitaxy relationship and in-plane orientations between relaxed Ge and SiC(0001). Typical transmission electron diffraction patterns indicate that Ge grows according to only one epitaxy relationship Ge{111}||SiC(0001) that corresponds to two in-plane orientations, a preferential one and a minority one rotated by 30° around the growth 〈111〉-Ge (or [0001]-SiC) axis. Double spot RHEED patterns also point out a twinning for each in-plane orientation, a consequence of the three-fold order of the 〈111〉-Ge axis. [Copyright &y& Elsevier]