Abstract: A semiconductor structure includes a first MOS device including a first gate, and a second MOS device including a second gate. The first gate includes a first high-k dielectric over a semiconductor substrate; a second high-k dielectric over the first high-k dielectric; a first metal layer over the second high-k dielectric, wherein the first metal layer dominates a work-function of the first MOS device; and a second metal layer over the first metal layer. The second gate includes a third high-k dielectric over the semiconductor substrate, wherein the first and the third high-k dielectrics are formed of same materials, and have substantially a same thickness; a third metal layer over the third high-k dielectric, wherein the third metal layer and the second metal layer are formed of same materials, and have substantially a same thickness; and a fourth metal layer over the third metal layer.

Abstract: A semiconductor structure with a metal gate structure includes a first type field-effect transistor having a first gate including: a high k dielectric material on a substrate, a first metal layer on the high k dielectric material layer and having a first work function, and a first aluminum layer on the first metal layer. The first aluminum layer includes an interfacial layer including aluminum, nitrogen and oxygen. The device also includes a second type field-effect transistor having a second gate including: the high k dielectric material on the substrate, a second metal layer on the high k dielectric material layer and having a second work function different from the first work function, and a second aluminum layer on the second metal layer.

Abstract: The present disclosure provides a semiconductor device that includes a semiconductor substrate and a transistor formed in the substrate. The transistor includes a gate stack having a high-k dielectric and metal gate, a sealing layer formed on sidewalls of the gate stack, the sealing layer having an inner edge and an outer edge, the inner edge interfacing with the sidewall of the gate stack, a spacer formed on the outer edge of the sealing layer, and a source/drain region formed on each side of the gate stack, the source/drain region including a lightly doped source/drain (LDD) region that is aligned with the outer edge of the sealing layer.

Abstract: A semiconductor structure with a metal gate structure includes a first type field-effect transistor having a first gate including: a high k dielectric material on a substrate, a first metal layer on the high k dielectric material layer and having a first work function, and a first aluminum layer on the first metal layer. The first aluminum layer includes an interfacial layer including aluminum, nitrogen and oxygen. The device also includes a second type field-effect transistor having a second gate including: the high k dielectric material on the substrate, a second metal layer on the high k dielectric material layer and having a second work function different from the first work function, and a second aluminum layer on the second metal layer.

Abstract: The present disclosure also provides another embodiment of a method for making metal gate stacks. The method includes forming a first dummy gate and a second dummy gate on a substrate; removing a polysilicon layer from the first dummy gate, resulting in a first gate trench; forming a first metal layer and a first aluminum layer in the first gate trench; applying a chemical mechanical polishing (CMP) process to the substrate; performing an annealing process to the first aluminum layer using a nitrogen and oxygen containing gas, forming an interfacial layer of aluminum, nitrogen and oxygen on the first aluminum layer; thereafter removing the polysilicon layer from the second dummy gate, resulting in a second gate trench; and forming a second metal layer and a second aluminum layer on the second metal layer in the second gate trench.

Abstract: The present disclosure also provides another embodiment of a method for making metal gate stacks. The method includes forming a first dummy gate and a second dummy gate on a substrate; removing a polysilicon layer from the first dummy gate, resulting in a first gate trench; forming a first metal layer and a first aluminum layer in the first gate trench; applying a chemical mechanical polishing (CMP) process to the substrate; performing an annealing process to the first aluminum layer using a nitrogen and oxygen containing gas, forming an interfacial layer of aluminum, nitrogen and oxygen on the first aluminum layer; thereafter removing the polysilicon layer from the second dummy gate, resulting in a second gate trench; and forming a second metal layer and a second aluminum layer on the second metal layer in the second gate trench.

Abstract: The present disclosure provides a semiconductor device that includes a semiconductor substrate and a transistor formed in the substrate. The transistor includes a gate stack having a high-k dielectric and metal gate, a sealing layer formed on sidewalls of the gate stack, the sealing layer having an inner edge and an outer edge, the inner edge interfacing with the sidewall of the gate stack, a spacer formed on the outer edge of the sealing layer, and a source/drain region formed on each side of the gate stack, the source/drain region including a lightly doped source/drain (LDD) region that is aligned with the outer edge of the sealing layer.

Abstract: A semiconductor structure includes a first MOS device including a first gate, and a second MOS device including a second gate. The first gate includes a first high-k dielectric over a semiconductor substrate; a second high-k dielectric over the first high-k dielectric; a first metal layer over the second high-k dielectric, wherein the first metal layer dominates a work-function of the first MOS device; and a second metal layer over the first metal layer. The second gate includes a third high-k dielectric over the semiconductor substrate, wherein the first and the third high-k dielectrics are formed of same materials, and have substantially a same thickness; a third metal layer over the third high-k dielectric, wherein the third metal layer and the second metal layer are formed of same materials, and have substantially a same thickness; and a fourth metal layer over the third metal layer.