Method for manufacturing a semiconductor device comprising transistors each having a different effective work function

摘要

The method for manufacturing a semiconductor device comprising transistors each having a different work function arranged along a main surface of a substrate, comprising:
- providing at least two channel regions in the substrate;
- providing a dielectric layer on the substrate;
- providing openings in the dielectric layer thereby providing corresponding gate regions on the channel regions;
- providing a gate dielectric layer in the openings on the gate regions;
- providing on the gate dielectric layer on each of the gate regions a barrier layer stack having different thickness along the different gate regions;
- providing a gate filling stack of metal layers on the barrier layer stack in each of the gate regions;
wherein providing the barrier layer stack comprises:
- providing a first barrier layer on the gate dielectric layer in the openings on each of the gate regions;
- selectively removing the first barrier layer in a subset of the gate regions, leaving the first barrier layer on at least a complementary subset of the gate regions;
and repeating at least once the step of:
- providing a subsequent barrier layer in the openings on each of the channel regions;
- selectively removing the subsequent barrier layer in a respective subset of the channel regions, leaving the respective subsequent barrier layer in a respective complementary subset of the channel regions; such that barrier layer stacks having different thickness along different gate regions are provided.