The mean size of dome clusters grown by molecular beam epitaxy of pure Ge onto Si(100) at substrate temperatures, T, of 550°C und 650°C is deposition rate dependent. For samples with nominal Ge coverages near 8 ML (1 ML = 6.78 × 1014 atoms/cm2) and deposition rates between 1.4 and 17.5 ML/min, higher deposition rates decreased the mean dome diameter und increased the dome areal density. Additionally, the critical volume for the pyramid-to-dome transition decreases with increasing deposition rate for islands grown between T= 550°C and 650°C. By this measure, the Ge content of the dome clusters rises with increasing deposition rate. Quantitative, nm-resolved electron energy loss spectroscopy (EELS) measurements taken in a scanning transmission electron microscope confirm these results. For domes grown at T = 650°C with rates of 1.4 ML/min and 17.5 ML/min, EELS indicates 59% and 70% Ge compositions, respectively. These results show that dome cluster composition may be kinetically controlled by varying the Ge deposition rate.