# US 2008/0185656 A1 · Semiconductor device and method for manufacturing the same

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- Number: US 2008/0185656 A1
- Document ID: US20080185656A1
- Status: Published application
- Kind: A1
- Application number: 11/907,353
- Filed: 2007-10-11
- Published: 2008-08-07
- Earliest claimed: 2007-02-05
- Assignees: Kabushiki Kaisha Toshiba
- Inventors: Masato Koyama; Yoshinori Tsuchiya; Seiji Inumiya
- Web page: https://patentgrep.com/patent/US20080185656A1

## CPC

- H10D 84/038: {using silicon technology, e.g. SiGe}
- H10D 64/0132: {the conductor being a metallic silicide}
- H10D 64/017: {using dummy gates in processes wherein at least parts of the final gates are self-aligned to the dummy gates, i.e. replacement gate processes}
- H10D 64/668: {the layer being a silicide, e.g. TiSi2}
- H10D 64/691: {comprising metallic compounds, e.g. metal oxides or metal silicates (insulators comprising nitrogen H10D64/693)}
- H10D 84/0174: {the gate conductors being silicided}
- H10D 84/0177: {the gate conductors having different materials or different implants}
- H10D 84/0181: {Manufacturing their gate insulating layers}
- H10D 30/0212: {using self-aligned silicidation}
- H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES

## Abstract

It is made possible to provide a method for manufacturing a semiconductor device that includes CMISs each having a low threshold voltage Vth and a Ni-FUSI/SiON or high-k gate insulating film structure. The method comprises: forming a p-type semiconductor region and an n-type semiconductor region insulated from each other in a substrate; forming a first and second gate insulating films on the p-type and n-type semiconductor regions, respectively; forming a first nickel silicide having a composition of Ni/Si<31/12 above the first gate insulating film, and a second nickel silicide having a composition of Ni/Si≧31/12 on the second gate insulating film; and segregating aluminum at an interface between the first nickel silicide and the first gate insulating film by diffusing aluminum through the first nickel silicide.

## Claims

### Claim 1

A method for manufacturing a semiconductor device, comprising:
forming a p-type semiconductor region and an n-type semiconductor region insulated from each other in a substrate;
forming a first and second gate insulating films on the p-type and n-type semiconductor regions, respectively;
forming a first nickel silicide having a composition of Ni/Si<31/12 above the first gate insulating film, and a second nickel silicide having a composition of Ni/Si≧31/12 on the second gate insulating film; and
segregating aluminum at an interface between the first nickel silicide and the first gate insulating film by diffusing the aluminum through the first nickel silicide.

### Claim 2 (depends on 1)

The method according to claim 1, wherein the forming the first and second nickel silicides includes:
forming first and second silicon layers on the first and second gate insulating films, respectively;
forming a third silicon layer by thinning the second silicon layer;
forming nickel layers of the same film thickness on the first silicon layer and the third silicon layer; and
causing solid phase reactions between the nickel layer and the first silicon layer and between the nickel layer and the third silicon layer by performing heat treatment.

### Claim 3 (depends on 1)

The method according to claim 1, wherein the forming the first and second nickel silicides includes:
forming first and second silicon layers on the first and second gate insulating films, respectively;
forming first and second silicon germanium compound layers on the first and second silicon layers, respectively;
selectively removing the first and second silicon germanium compound layers;
forming a third silicon layer by thinning the second silicon layer;
forming nickel layers of the same film thickness on the first silicon layer and the third silicon layer; and
causing solid phase reactions between the nickel layer and the first silicon layer and between the nickel layer and the third silicon layer by performing heat treatment.

### Claim 4 (depends on 1)

The method according to claim 1, wherein the forming the first and second nickel silicides includes:
forming first and second silicon layers on the first and second gate insulating films, respectively;
forming a first nickel layer on the first and second silicon layers;
forming the first nickel silicide by causing solid phase reactions between the first nickel layer and the first silicon layer and between the first nickel layer and the second silicon layer through heat treatment;
forming a second nickel layer on the first nickel silicide located above the n-type semiconductor region; and
turning at least a part of the first nickel silicide located above the n-type semiconductor region into the second nickel silicide by performing heat treatment.

### Claim 5 (depends on 4)

The method according to claim 4, further comprising
forming a layer containing one of titanium, zirconium, and hafnium on the first nickel silicide above the n-type semiconductor region, the forming the layer being carried out between the forming the second nickel layer and the turning at least a part of the first nickel silicide located above the n-type semiconductor region into the second nickel silicide.

### Claim 6 (depends on 4)

The method according to claim 4, wherein the turning at least a part of the first nickel silicide into the second nickel silicide includes turning all the nickel silicide located above the n-type semiconductor region into the second nickel silicide.

### Claim 7 (depends on 1)

The method according to claim 1, wherein the segregating the aluminum at the interface between the first nickel silicide and the first gate insulating film includes:
forming an aluminum layer on the first and second nickel silicides; and
diffusing the aluminum through the first nickel silicide by performing heat treatment.

### Claim 8 (depends on 7)

The method according to claim 7, wherein the segregating the aluminum includes:
segregating the aluminum having a thickness of one atomic layer or greater at the interface between the first nickel silicide and the first gate insulating film; and
segregating the aluminum having a thickness thinner than one atomic layer at an interface between the second nickel silicide and the second gate insulating film.

### Claim 9 (depends on 1)

The method according to claim 1, wherein the segregating the aluminum at the interface between the first nickel silicide and the first gate insulating film includes:
implanting aluminum ions in the first and second nickel silicides; and
diffusing the aluminum in the first nickel silicide by performing heat treatment.

### Claim 10

A method for manufacturing a semiconductor device, comprising:
forming a p-type semiconductor region and an n-type semiconductor region insulated from each other in a substrate;
forming a first and second gate insulating films on the p-type and n-type semiconductor regions, respectively;
forming a first nickel silicide made of one of NiSi2 cubic, NiSi orthorhombic, and Ni2Si orthorhombic on the first gate insulating film, and a second nickel silicide made of at least one of Ni31Si12 hexagonal and Ni3Si cubic on the second gate insulating film; and
segregating aluminum at an interface between the first nickel silicide and the first gate insulating film by diffusing the aluminum through the first nickel silicide.

### Claim 11 (depends on 10)

The method according to claim 10, wherein the forming the first and second nickel silicides includes:
forming first and second silicon layers on the first and second gate insulating films, respectively;
forming a third silicon layer by thinning the second silicon layer;
forming nickel layers of the same film thickness on the first silicon layer and the third silicon layer; and
causing solid phase reactions between the nickel layer and the first silicon layer and between the nickel layer and the third silicon layer by performing heat treatment.

### Claim 12 (depends on 10)

The method according to claim 10, wherein the forming the first and second nickel silicides includes:
forming first and second silicon layers on the first and second gate insulating films, respectively;
forming first and second silicon germanium compound layers on the first and second silicon layers, respectively;
selectively removing the first and second silicon germanium compound layers;
forming a third silicon layer by thinning the second silicon layer;
forming nickel layers of the same film thickness on the first silicon layer and the third silicon layer; and
causing solid phase reactions between the nickel layer and the first silicon layer and between the nickel layer and the third silicon layer by performing heat treatment.

### Claim 13 (depends on 10)

The method according to claim 10, wherein the forming the first and second nickel silicides includes:
forming first and second silicon layers on the first and second gate insulating films, respectively;
forming a first nickel layer on the first and second silicon layers;
forming the first nickel silicide by causing solid phase reactions between the first nickel layer and the first silicon layer and between the first nickel layer and the second silicon layer through heat treatment;
forming a second nickel layer on the first nickel silicide located above the n-type semiconductor region; and
turning at least a part of the first nickel silicide located above the n-type semiconductor region into the second nickel silicide by performing heat treatment.

### Claim 14 (depends on 13)

The method according to claim 13, further comprising
forming a layer containing one of titanium, zirconium, and hafnium on the first nickel silicide above the n-type semiconductor region, the forming the layer being carried out between the forming the second nickel layer and the turning at least a part of the first nickel silicide located above the n-type semiconductor region into the second nickel silicide.

### Claim 15 (depends on 13)

The method according to claim 13, wherein the turning at least a part of the first nickel silicide into the second nickel silicide includes turning all the nickel silicide located above the n-type semiconductor region into the second nickel silicide.

### Claim 16 (depends on 10)

The method according to claim 10, wherein the segregating the aluminum at the interface between the first nickel silicide and the first gate insulating film includes:
forming an aluminum layer on the first and second nickel silicides; and
diffusing the aluminum through the first nickel silicide by performing heat treatment.

### Claim 17 (depends on 16)

The method according to claim 16, wherein the segregating the aluminum includes:
segregating the aluminum having a thickness of one atomic layer or greater at the interface between the first nickel silicide and the first gate insulating film; and
segregating the aluminum having a thickness thinner than one atomic layer at an interface between the second nickel silicide and the second gate insulating film.

### Claim 18 (depends on 10)

The method according to claim 10, wherein the segregating the aluminum at the interface between the first nickel silicide and the first gate insulating film includes:
implanting aluminum ions in the first and second nickel silicides; and
diffusing the aluminum in the first nickel silicide by performing heat treatment.

### Claim 19

A semiconductor device comprising:
a substrate;
an n-channel MIS transistor including:
a p-type semiconductor region formed in the substrate;
first source/drain regions formed at a distance from each other in the p-type semiconductor region;
a first gate insulating film formed on the p-type semiconductor region between the first source/drain regions;
a first gate electrode including a first nickel silicide having a composition of Ni/Si<31/12 formed above the first gate insulating film; and
a first aluminum layer segregated at an interface between the first gate insulating film and the first gate electrode; and
a p-channel MIS transistor including:
an n-type semiconductor region insulated from the p-type semiconductor region and formed in the substrate;
second source/drain regions formed at a distance from each other in the n-type semiconductor region;
a second gate insulating film formed on the r-type semiconductor region between the second source/drain regions; and
a second gate electrode including a second nickel silicide having a composition of Ni/Si<31/12 formed above the second gate insulating film, and a third nickel silicide having a composition of Ni/Si≧31/12 formed above the second nickel silicide.

### Claim 20 (depends on 19)

The device according to claim 19, wherein:
each of the first and second nickel silicides is one of NiSi2 cubic, NiSi orthorhombic, and Ni2Si orthorhombic, and
the third nickel silicide is one of Ni31Si12 hexagonal and Ni3Si cubic.

### Claim 21 (depends on 19)

The device according to claim 19, further comprising a second aluminum layer thinner than one atomic layer formed in an interface between the second nickel silicide and the second gate insulating film, and
wherein the first aluminum layer has a layer thickness of one atomic layer or greater.