A method includes forming a fin protruding from a semiconductor substrate, forming source/drain features in the fin, forming a metal gate structure over the fin and interposed between the source/drain features, recessing the metal gate structure to form a trench, depositing a first metal layer to partially fill the trench, depositing a second metal layer to completely fill the trench, and planarizing the second meal layer. The second metal layer differs from the first metal layer in composition, and the second metal layer includes tungsten (W).