Structural and charge trapping properties of two bilayer $(Ge+SiO2)/SiO2$ films deposited on rippled substrate

We report on structural properties and charge trapping in $[(Ge+SiO2)/SiO2]×2$ films deposited by magnetron sputtering on a periodically corrugated-rippled substrate and annealed in vacuum and forming gas. The rippled substrate caused a self-ordered growth of Ge quantum dots, while annealing in different environments enabled us to separate charge trapping in quantum dots from the trapping at the dot-matrix and matrix-substrate interfaces. We show that the charge trapping occurs mainly in Ge quantum dots in the films annealed in the forming gas, while $Si–SiO2$ interface trapping is dominant for the vacuum annealed films.