Semiconductor device with dual workfunction gate electrodes and its method of fabrication

摘要

The present invention provides a method for forming a dual workfunction semiconductor device comprising a first and second control electrode (17,18) comprising a metal-semiconductor compound, e.g. a silicide or a germanide, and a dual workfunction semiconductor device thus obtained. The method comprises forming a blocking region (23) for preventing diffusion of metal from the metal-semiconductor compound of the first control electrode (17) to the metal-semiconductor compound of the second control electrode (18), the blocking region (23) being formed at a location where an interface (21) between the first and second control electrodes (17,18) will be formed or is formed. By preventing metal to diffuse from the one to the other control electrode (17,18) the constitution of the metal-semiconductor compounds of the first and second control electrodes (17,18) may remain substantially unchanged during e.g. thermal steps in further processing of the device.