The growth of Ge on the H-terminated Si(111) surface was investigated using UHV scanning tunneling microscopy. Hydrogen termination was treated with 1% HF and germanium was deposited at room temperature. After the deposition these samples were annealed at 400, 500 and 600 degrees C, respectively. At 400 degrees C, hydrogen atoms prevented germanium from diffusing on the surface, resulting in the formation of a lot of small two-dimensional islands. For samples annealed at 600 degrees C, the critical thickness increased more than that of the growth on the clean Si surface.