Abstract: Disclosed herein is a method for forming a dual gate of a semiconductor device. The method comprises the steps of forming a first polysilicon layer doped with p-type impurity ions and a second polysilicon layer doped with n-type impurity ions on a first region and a second region of a semiconductor substrate, respectively, and sequentially subjecting the surfaces of the first and second polysilicon layers to wet cleaning, drying, and dry cleaning. The wet cleaning is performed by using a sulfuric acid peroxide mixture (SPM), a buffered oxide etchant (BOE), and Standard Clean-1 (SC-1) as cleaning solutions.