Atomic Diffusion Bonding of Wafers using a-Ge Films with Extremely Low Electrical Conductivity

Atomic diffusion bonding of wafers using amorphous Ge (a-Ge) films was studied. Results indicate that the surface roughness S
_a
of a-Ge films is expected to be less than 0.35 nm to obtain surface free energy at the bonded interface greater than 1 J/m
²
at the interface of bonded a-Ge(20 nm) films.