US 6,475,908 B1 · Dual metal gate process: metals and their silicides

Abstract

Methods for forming dual-metal gate CMOS transistors are described. An NMOS and a PMOS active area of a semiconductor substrate are separated by isolation regions. A metal layer is deposited over a gate dielectric layer in each active area. Silicon ions are implanted into the metal layer in one active area to form an implanted metal layer which is silicided to form a metal silicide layer. Thereafter, the metal layer and the metal silicide layer are patterned to form a metal gate in one active area and a metal silicide gate in the other active area wherein the active area having the gate with the higher work function is the PMOS active area. Alternatively, both gates may be metal silicide gates wherein the silicon concentrations of the two gates differ. Alternatively, a dummy gate may be formed in each of the active areas and covered with a dielectric layer. The dielectric layer is planarized thereby exposing the dummy gates. The dummy gates are removed leaving gate openings to the semiconductor substrate. A metal layer is deposited over a gate dielectric layer within the gate openings to form metal gates. One or both of the gates are silicon implanted and silicided. The PMOS gate has the higher work function.

Claims42

Dependent claims

A method of forming dual-metal gate CMOS transistors in the fabrication of integrated circuits comprising:

providing a first and a second active area of a semiconductor substrate separated by isolation regions wherein one of said active areas will be a PMOS area and the other of said active areas will be an NMOS area;
forming a gate dielectric layer overlying said semiconductor substrate in each of said active areas;
depositing a metal layer overlying said gate dielectric layer;
implanting silicon ions into said metal layer in said first active area to form an implanted metal layer and siliciding said implanted metal layer to form a metal silicide layer;
and
thereafter patterning said metal layer and said metal silicide layer to form a metal gate in said second active area and a metal silicide gate in said first active area wherein said PMOS area comprises one of said first and second active areas having a gate having a higher work function than said gate in the other of said active areas to complete formation said of dual-metal gate CMOS transistors in the fabrication of an integrated circuit.

3 more elements

A method of forming dual-metal gate CMOS transistors in the fabrication of integrated circuits comprising:

providing a first and a second active area of a semiconductor substrate separated by isolation regions wherein one of said active areas will be a PMOS area and the other of said active areas will be an NMOS area;
forming a gate dielectric layer overlying said semiconductor substrate in each of said active areas;
depositing a metal layer overlying said gate dielectric layer;
implanting first silicon ions into said metal layer in said first active area to form an implanted metal layer and siliciding said implanted metal layer to form a first metal silicide layer;
implanting second silicon ions into said metal layer in said second active area to form an implanted metal layer and siliciding said implanted metal layer to form a second metal silicide layer wherein said first metal silicide layer has a different silicon concentration from said second metal silicide layer;
and
thereafter patterning said first and second metal silicide layers to form a first metal silicide gate in said first active area and a second metal silicide gate in said second active area wherein said PMOS area comprises one of said first and second active areas having a gate having a higher work function than said gate in the other of said active areas to complete formation said of dual-metal gate CMOS transistors in the fabrication of an integrated circuit.

4 more elements

A method of forming dual-metal gate CMOS transistors in the fabrication of integrated circuits comprising:

providing a first and a second active area of a semiconductor substrate separated by isolation regions wherein one of said active areas will be a PMOS area and the other of said active areas will be an NMOS area;
forming a dummy gate in each of said active areas;
covering said dummy gates with a dielectric layer;
planarizing said dielectric layer whereby a top surface of each of said dummy gates is exposed;
removing said exposed dummy gates leaving gate openings to said semiconductor substrate;
forming a gate dielectric layer overlying said semiconductor substrate in each of said gate openings;
depositing a metal layer within said gate openings to form metal gates;
implanting first silicon ions into said metal gate only in said first active area to form an implanted metal gate and siliciding said implanted metal gate to form a first metal silicide gate in said first active area;
and
implanting second silicon ions into said metal gate only in said second active area to form an implanted metal gate and siliciding said implanted metal gate to form a second metal silicide gate in said second active area wherein said PMOS area comprises one of said first and second active areas having a gate having a higher work function than said gate in the other of said active areas to complete formation said of dual-metal gate CMOS transistors in the fabrication of an integrated circuit.

7 more elements

A method of forming dual-metal gate CMOS transistors in the fabrication of integrated circuits comprising:

providing a first and a second active area of a semiconductor substrate separated by isolation regions wherein one of said active areas will be a PMOS area and the other of said active areas will be an NMOS area;
forming a gate dielectric layer overlying said semiconductor substrate in each of said active areas;
depositing a first metal silicide layer overlying said gate dielectric layer;
implanting silicon ions into said first metal silicide layer in said first active area and siliciding implanted said first metal silicide layer to form a second metal silicide layer having a different silicon concentration than said first metal silicide layer;
and
thereafter patterning said first and second metal silicide layers to form a first metal silicide gate in said first active area and a second metal silicide gate in said second active area wherein said PMOS area comprises one of said first and second active areas having a gate having a higher work function than said gate in the other of said active areas to complete formation said of dual-metal gate CMOS transistors in the fabrication of an integrated circuit.

3 more elements

Dependencies are inferred from the claim text.

Dual metal gate process: metals and their silicides

Life of this patent

Dual metal gate process: metals and their silicides

Life of this patent

Abstract

Claims42