The present application discloses method for fabricating a conductive feature and a method for fabricating a semiconductor device. The method includes providing a substrate; forming a recess in the substrate; conformally forming a first nucleation layer in the recess; performing a post-treatment to the first nucleation layer; and forming a first bulk layer on the first nucleation layer to fill the recess. The first nucleation layer and the first bulk layer configure the conductive feature. The first nucleation layer and the first bulk layer include tungsten. The post-treatment includes a borane-containing reducing agent.