The present disclosure relates to a method for fabricating a semiconductor structure. The method includes providing a substrate with a gate structure, an insulating structure over the gate structure, and a S/D region; depositing a titanium silicide layer over the S/D region with a first chemical vapor deposition (CVD) process. The first CVD process includes a first hydrogen gas flow. The method also includes depositing a titanium nitride layer over the insulating structure with a second CVD process. The second CVD process includes a second hydrogen gas flow. The first and second CVD processes are performed in a single reaction chamber and a flow rate of the first hydrogen gas flow is higher than a flow rate of the second hydrogen gas flow.