A CMOS structure is disclosed in which a first type FET contains a liner, which liner has oxide and nitride portions. The nitride portions are forming the edge segments of the liner. These nitride portions are capable of preventing oxygen from reaching the high-k dielectric gate insulator of the first type FET. A second type FET device of the CMOS structure has a liner without nitride portions. As a result, an oxygen exposure is capable to shift the threshold voltage of the second type of FET, without affecting the threshold value of the first type FET. The disclosure also teaches methods for producing the CMOS structure in which differing type of FET devices have their threshold values set independently from one another.