Effect of in situ plasma treatment on high-k films after high-k removal with plasma etching from the S/D region

In this work, a plasma etch technique for removing high-k dielectric from the source and drain (S/D) areas after metal/high-k gate stack patterning has been developed. To cure the plasma damage induced during the plasma etch of high-k films, an in situ plasma treatment with O₂ or N₂ was applied to several high-k compositions. This plasma process induces no structural weaknesses and exhibits excellent electrical performance (gate leakage current, I_on/I_off ratio, gate-induced drain leakage, and threshold voltage distribution) after an in situ plasma (O₂) treatment. Therefore, the results indicate that this plasma etch process is suitable for low power and high performance CMOS applications, particularly in short channel devices.