A semiconductor device includes a base substrate and a semiconductor chip on the base substrate, the semiconductor chip including a first layer structure and a second layer structure opposite to the first layer structure, at least one of the first and second layer structures including a semiconductor device portion, and a bonding structure between the first layer structure and the second layer structure, the bonding structure including a silver-tin (Ag—Sn) compound and a nickel-tin (Ni—Sn) compound.