Characterization of SiGe quantum dots on SiO2 and HfO2 grown by rapid thermal chemical deposition for nanoelectronic devices

Silicon-germanium quantum dot growth between 500 and 525degreesC using a Si2H6/GeH4/H-2-based chemistry was studied. The nucleation and growth of the SiGe dots were quantified by measuring the nuclei density and the concentration of Ge on SiO2 and HfO2 using scanning electron microscopy and atomic force microscopy. The effect of GeH4 and Si2H6 pretreatment on the SiO2 surface was investigated. It was found that Si atoms dominate the formation of the critical nuclei and Ge atoms impinge on these Si atoms to grow the SiGe dots. The Si atoms that terminate defect sites on SiO2 and the Si2H6 partial pressure determine the densities of SiGe dots. The growth of SiGe dots is limited by the GeH4 partial pressure, which reduces the activation energy of disilane decompositions in the surface-reaction-limited regime and desorption sites of H from the substrate. (C) 2003 The Electrochemical Society.