The influence of growth parameters and substrate material on the basic processes during strain-induced InAs-quantum dot (QD) formation and the resulting structural properties of the QDs is studied with reflection high-energy electron diffraction (RHEED), atomic force microscopy (AFM), and X-ray diffraction. The process of strain-induced QD formation is strongly influenced by the intermixing with substrate material and the desorption of indium at high temperatures. From the experimental results, we conclude that the strain-energy modification due to temperature-dependent intermixing has a larger influence on QD formation than temperature-dependent kinetic processes at the surface. Interestingly, we also find that the maximum growth temperature limited by desorption depends on the growth speed.