Abstract: After forming a material stack including a gate dielectric, a work function metal and a cobalt gate electrode in a gate cavity formed by removing a sacrificial gate structure, the cobalt gate electrode is recessed by oxidizing the cobalt gate electrode to provide a cobalt oxide layer on a surface of the cobalt gate electrodes and removing the cobalt oxide layer from the surface of the cobalt gate electrodes by a chemical wet etch. The oxidation and oxide removal steps can be repeated until the cobalt gate electrode is recessed to any desired thickness. The work function metal can be recessed after the recessing of the cobalt gate electrode is completed or during the recessing of the cobalt gate electrode.

Abstract: After forming a material stack including a gate dielectric, a work function metal and a cobalt gate electrode in a gate cavity formed by removing a sacrificial gate structure, the cobalt gate electrode is recessed by oxidizing the cobalt gate electrode to provide a cobalt oxide layer on a surface of the cobalt gate electrodes and removing the cobalt oxide layer from the surface of the cobalt gate electrodes by a chemical wet etch. The oxidation and oxide removal steps can be repeated until the cobalt gate electrode is recessed to any desired thickness. The work function metal can be recessed after the recessing of the cobalt gate electrode is completed or during the recessing of the cobalt gate electrode.

Abstract: After forming a material stack including a gate dielectric, a work function metal and a cobalt gate electrode in a gate cavity formed by removing a sacrificial gate structure, the cobalt gate electrode is recessed by oxidizing the cobalt gate electrode to provide a cobalt oxide layer on a surface of the cobalt gate electrodes and removing the cobalt oxide layer from the surface of the cobalt gate electrodes by a chemical wet etch. The oxidation and oxide removal steps can be repeated until the cobalt gate electrode is recessed to any desired thickness. The work function metal can be recessed after the recessing of the cobalt gate electrode is completed or during the recessing of the cobalt gate electrode.

Abstract: After forming a material stack including a gate dielectric, a work function metal and a cobalt gate electrode in a gate cavity formed by removing a sacrificial gate structure, the cobalt gate electrode is recessed by oxidizing the cobalt gate electrode to provide a cobalt oxide layer on a surface of the cobalt gate electrodes and removing the cobalt oxide layer from the surface of the cobalt gate electrodes by a chemical wet etch. The oxidation and oxide removal steps can be repeated until the cobalt gate electrode is recessed to any desired thickness. The work function metal can be recessed after the recessing of the cobalt gate electrode is completed or during the recessing of the cobalt gate electrode.

Abstract: After forming a material stack including a gate dielectric, a work function metal and a cobalt gate electrode in a gate cavity formed by removing a sacrificial gate structure, the cobalt gate electrode is recessed by oxidizing the cobalt gate electrode to provide a cobalt oxide layer on a surface of the cobalt gate electrodes and removing the cobalt oxide layer from the surface of the cobalt gate electrodes by a chemical wet etch. The oxidation and oxide removal steps can be repeated until the cobalt gate electrode is recessed to any desired thickness. The work function metal can be recessed after the recessing of the cobalt gate electrode is completed or during the recessing of the cobalt gate electrode.

Abstract: After forming a material stack including a gate dielectric, a work function metal and a cobalt gate electrode in a gate cavity formed by removing a sacrificial gate structure, the cobalt gate electrode is recessed by oxidizing the cobalt gate electrode to provide a cobalt oxide layer on a surface of the cobalt gate electrodes and removing the cobalt oxide layer from the surface of the cobalt gate electrodes by a chemical wet etch. The oxidation and oxide removal steps can be repeated until the cobalt gate electrode is recessed to any desired thickness. The work function metal can be recessed after the recessing of the cobalt gate electrode is completed or during the recessing of the cobalt gate electrode.

Abstract: Methods for fabricating interface passivation layers in a circuit structure are provided. The method includes forming a silicon-germanium layer over a substrate, removing a native oxide layer from an upper surface of the silicon-germanium layer, and exposing the upper surface of the silicon-germanium layer to an ozone-containing solution, resulting in an interface passivation layer with a higher concentration of germanium-dioxide present than germanium-oxide. The resulting interface passivation layer may be part of a gate structure, in which the channel region of the gate structure includes the silicon-germanium layer and the interface passivation layer between the channel region and the dielectric layer of the gate structure has a high concentration of germanium-dioxide.