When forming sophisticated gate electrode structures, such as high-k metal gate electrode structures, an appropriate encapsulation may be achieved, while also undue material loss of a strain-inducing semiconductor material that is provided in one type of transistor may be avoided. To this end, the patterning of the protective spacer structure prior to depositing the strain-inducing semiconductor material may be achieved for each type of transistor on the basis of the same process flow, while, after the deposition of the strain-inducing semiconductor material, an etch stop layer may be provided so as to preserve integrity of the active regions.