Self-Assemble Formation of Ge Dots on Si(100) via C/Ge/C/Si Structure

Abstract

Formation of Ge dots via C2/Ge/C1/Si structure through solid-phase epitaxy by subsequent annealing at 650C in a molecular beam epitaxy chamber was investigated. The dot density increased with C1 coverage similar to the case of Ge/C1/Si structure. This suggests that Si-C bonds at Ge/Si interface are effective to form small and dense Ge dots. The smallest and densest dots were formed for C1 = 0.5 ML and C2 = 0.1 ML with mean diameter and dot density of 28.3 nm and 9.6 × 1010 cm-2, respectively. However, the dot size and density of C2/Ge/C1/Si structure was 1.3 times lager and 0.6 times lower than those of Ge/C1/Si structure in the case of C1 = 0.5 ML. As a result, it was found that Ge dots became large due to interference with the effect of reducing dot size in Ge/C1/Si structure.