Formation of atomic-scale germanium quantum dots by selective oxidation of SiGe/Si-on-insulator

A complementary metal-oxide-semiconductor-compatible method is proposed to form atomic-scale germanium (Ge) quantum dots $(<10 nm)$ for application in single-electron devices or optical devices. The formation of Ge quantum dots is realized by the Ge atoms’ segregation and agglomeration during thermal oxidation of $Si1−xGex$ alloys. The size and distribution of the Ge dots are determined by conditions of thermal oxidation process and Ge content in the alloys. An average Ge-dot size of 5.1 nm with standard deviation of 1.79 nm and a comparatively uniform spatial distribution (dot density of $7.9×1011 cm−2)$ could be obtained by selective oxidation of $Si0.85Ge0.15/Si$-on-insulator structure.