Grazing incidence x-ray diffraction and atomic force microscopy investigations of germanium dots grown on silicon (001) by successive depositions of germanium through a thin silicon oxide layer

Abstract

Structural properties of high density, nanometric size germanium dots grown on a silicon (001) surface covered by a very thin (1.2 nm thick) silicon oxide layer have been investigated by in-situ grazing incidence x-ray diffraction (GIXD) and ex-situ atomic force microscopy. Growth under molecular nitrogen partial pressure of 10−5 Torr yielded a high density (∼4×1010/cm2) of dots. The dot size can be progressively increased by successive depositions of germanium. GIXD investigations show that dots grow in epitaxial relationship to the silicon (001) substrate and that after few successive depositions, the dots are composed of pure and fully relaxed germanium.