Selective growth of Ge quantum dots on chemically prepared SiO2/Si(001) surfaces

We report, in this paper, on selective growth of Si buffer layers and of Ge quantum dots on thermally desorbed SiO2/Si surfaces. The oxide layers with a thickness of about 6–8 Å were chemically grown by using the standard wet Radio Corporation of America (RCA) cleaning method. We show that both the oxide desorption process and the growth of Si buffer layers can be monitored by using in situ reflection high energy electron diffraction. The growth of Si buffer layers is showed to process via the formation of pyramidal islands formed by {113} facets. Those facets grow until the (001) top layer disappears and are showed to be an additional parameter to control the nucleation process of Ge dots. By monitoring the facet formation during Si growth, we show that it is possible to form one Ge dot per window.