摘要:
A method for manufacturing a MOS transistor is provided. A substrate has a high-k dielectric layer and a barrier in each of a first opening and a second opening formed by removing a dummy gate and located in a first transistor region and a second transistor region. A dielectric barrier layer is formed on the substrate and filled into the first opening and the second opening to cover the barrier layers. A portion of the dielectric barrier in the first transistor region is removed. A first work function metal layer is formed. The first work function metal layer and a portion of the dielectric barrier layer in the second transistor region are removed. A second work function metal layer is formed. The method can avoid a loss of the high-k dielectric layer to maintain the reliability of a gate structure, thereby improving the performance of the MOS transistor.