The technical potential of room temperature bonding of wafers in vacuum using amorphous Si (a-Si) and Ge (a-Ge) films was studied. Transmission electron microscopy images revealed no interface corresponding to the original films surfaces for bonded a-Ge-a-Ge films. Analyses of film structure and the surface free energy at the bonded interface revealed higher bonding potential at the connected a-Ge-a-Ge interface than that of a-Si films. The electrical resistivity of a-Ge films is 0.62 flm, which is lower than that of a-Si film (4.7 Ωm), but 7-8 order higher than that of representative material films used for bonding in vacuum. Our results indicate that room temperature bonding using a-Ge films is useful to bond wafers without any marked influence on the electrical properties of devices on wafer surfaces caused by the electrical conductivity of films used for bonding.