Method of fabricating dual gate

A method of fabricating a dual gate, comprising:

• providing a first conductive type region and a second conductive type region isolated by an isolation structure;
• forming a polysilicon layer which comprises a first part covering the first conductive type region and a second part covering the second conductive type region,
• converting the first part of the polysilicon layer into a first conductive type polysilicon layer;
• forming a diffusion layer containing second type conductive ions to cover the first part of the polysilicon layer;
• performing a first thermal process to convert the second part of the polysilicon layer into a second conductive type polysilicon layer;
• forming a metal layer on the diffusion layer and the first conductive type polysilicon layer;
• transforming the metal layer into a metal silicide layer, and simultaneously, inducing a reaction between the metal layer and the diffusion layer;
• forming a dielectric layer on the metal silicide layer;
• and
• patterning the dielectric layer, the metal silicide layer, the reacted diffusion layer, the first and the second conductive type polysilicon layers to form a first conductive type gate on the first conductive region and a second conductive type gate on the second conductive type region.