the surface cleaning method of semiconductor substrate comprises , the steps of , immersing a substrate of a first conductive type having ge or sige mixing ge and si at least in the surface layer in a solution of hydrofluoric acid , and removing foreign matters from the surface of the substrate without overetching the surface of the substrate , pouring pure water on the substrate to wash away the solution of hydrofluoric acid applied at the step from the surface of the substrate , and immersing the substrate in a solution of hydrogen peroxide , and removing foreign matters from the surface of the substrate without overetching the surface of the substrate .