Effect of annealing on morphology of Si based Ge quantum dots grown by magnetron sputtering

Abstract

Silicon-based germanium quantum dots (Ge/Si QDs) have shown important application potential in optoelectronic devices due to their excellent properties, which made their controllable growth of morphology and structure become a research hotspot in recent years. This paper discussed the morphological evolution of Ge/Si QDs undergone different annealing, such as natural cooling, in-situ annealing followed by natural cooling, natural cooling followed by rising temperature for annealing, and natural cooling followed by moving the sample into a rapid annealing furnace for annealing. The formation process of QDs was analyzed based on the measurement results of atomic force microscope (AFM) and the thermodynamic and kinetic theories of thin film growth. The results showed that the influence of in-situ annealing in magnetron sputtering growth chamber on the morphology of QDs was different from that of annealing in rapid furnace due to the great difference of temperature-time curves between the two processes. Surprisingly, high-density and small-size Ge/Si QDs can be produced by using a process of in-situ natural cooling followed by rapid annealing, which provided a new idea for the preparation of high-quality QDs used for future devices.