US Patent 10121700 Semiconductor device and fabrication method thereof

Semiconductor devices and fabrication methods thereof are provided. An exemplary fabrication method includes providing a base substrate; forming gate structures over the base substrate; forming doped source/drain regions in the base substrate at two sides of each of the gate structures; forming an oxide layer on each of the doped source/drain regions; forming a metal layer on the oxide layer; and performing a reactive thermal annealing process, such that the metal layer reacts with a material of the oxide layer and a material of the doped source/drain regions to form a metal contact layer on each of the doped source/drain regions. The metal contact layer includes a first metal contact layer on the doped source/drain region, an oxygen-containing metal contact layer on the first metal contact layer, and a second metal contact layer on the oxygen-containing metal contact layer.