US Patent 10164048 Method for forming source/drain contacts

A method includes providing a structure that includes a substrate, a gate structure over the substrate, and a source/drain (S/D) feature including silicon germanium (SiGe) adjacent to the gate structure. The method further includes implanting gallium (Ga) into the S/D feature; performing a first annealing process at a first temperature to recrystallize the SiGe; depositing a conductive material including a metal over the S/D feature after the first annealing process; performing a second annealing process at a second temperature to cause reaction between the metal and the S/D feature; and performing a third annealing process at a third temperature to activate dopants including Ga in the S/D feature.