A method for removing surface oxide from polysilicon includes depositing a very thin layer of germanium (e.g. monolayers in thickness) over the polysilicon immediately before a subsequent polysilicon deposition step, and then heating the germanium-coated polysilicon in a vacuum to sublime (remove) volatile germanium oxide. This method is applied to formation of a trench capacitor, which uses either doped amorphous silicon or doped amorphous SiGe material in the formation of the electrodes.