A method includes etching a dummy gate to form an opening. A gate dielectric layer is deposited in the opening. A blocking layer is deposited over the gate dielectric layer, wherein the blocking layer has a bottom portion over a bottom of the opening and a sidewall portion over a sidewall of the opening. An adhesive layer is deposited over the bottom portion of the blocking layer. A metal layer is deposited over the adhesive layer, wherein the metal layer is in contact with the sidewall portion of the blocking layer.