JPH0714847A - Semiconductor device and manufacture thereof - Google Patents

Abstract

PURPOSE:To provide a semiconductor device on which a silicide layer, which will be formed on an impurity diffusion layer, is formed in such a manner that the leak current, generated on the end part of an element isolation insulating film, is suppressed. CONSTITUTION:In the semiconductor device on which a silicide layer 9 is formed on the impurity diffusion layer 7 formed on the element formation region of a semiconductor substrate 1, a silicide layer 9 is formed separately from the end part of an element isolation insulating film 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device and a method for manufacturing the same, and more particularly to a semiconductor device having a silicide layer formed on an impurity diffusion layer to reduce the resistance of the impurity diffusion layer and a method for manufacturing the same.

[0002]

2. Description of the Related Art In order to reduce the resistance of an impurity diffusion layer formed in an element formation region on the surface of a semiconductor substrate, for example, a source / drain diffusion layer 7 of an electric field transistor shown in FIG. 2, a silicide is selectively formed on the impurity diffusion layer 7. The method of forming layer 9 has been used. In FIG. 2, 1 is a semiconductor substrate, 3 is an element isolation insulating film, 4 is a gate electrode, and 10 is a PSG film.

[0003]

When the element isolation insulating film 3 is formed on the surface of the semiconductor substrate 1 by using the selective thermal oxidation method, the end portion thereof is formed into a beak shape called a bird's beak. As a result, stress concentrates on the semiconductor substrate 1 in the region in contact with the end portion of the element isolation insulating film 3 and a crystal defect occurs,
A leak current is generated in the P / N junction formed there.

When the silicide layer 9 is formed on the impurity diffusion layer 7 formed in the element formation region on the surface of the semiconductor substrate, crystal defects in the semiconductor substrate 1 in the region in contact with the end of the element isolation insulating film 3 are further expanded. The leakage current increases and the characteristics of the semiconductor device become unstable.

An object of the present invention is to eliminate this drawback, and a silicide layer formed on the impurity diffusion layer in order to reduce the resistance of the impurity diffusion layer formed in the element formation region on the semiconductor substrate surface. Another object of the present invention is to provide a semiconductor device formed so as to suppress a leak current generated at the end of the element isolation insulating film and a method for manufacturing the semiconductor device.

[0006]

Among the above-mentioned objects, a semiconductor device has a device isolation insulating film (3) formed on an impurity diffusion layer (7) formed in a device formation region on a semiconductor substrate (1). This is achieved by a semiconductor device in which a silicide layer (9) is formed apart from the end.

Among the above objects, the method of manufacturing a semiconductor device is a semiconductor substrate (1) in which an element isolation insulating film (3) is formed and an impurity diffusion layer (7) is formed in an element formation region.
An insulating film (8) is formed thereon, and the insulating film (8) is patterned to leave a peripheral region of the impurity diffusion layer (7) in contact with the end of the element isolation insulating film (3). Removing the impurity diffusion layer (7) from above and selectively forming a silicide layer (9) on the impurity diffusion layer (7) in the removed region of the insulating film (8). This is achieved by a method of manufacturing a semiconductor device having the same. Instead of forming the insulating film (8), a resist film may be formed and the resist film may be removed after the silicide layer (9) is formed.

Further, an element isolation insulating film (3) is formed,
A gate electrode (4) is formed in the element formation region, and an insulating film (1) is formed on the semiconductor substrate (1) in which the gate electrode (4) is sandwiched and the impurity diffusion layer (7) is formed in the element formation region. 6) is formed, and the insulating film (6) is anisotropically etched to form the insulating film (6) on the side wall of the gate electrode (4) and the end side wall of the element isolation insulating film (3). According to a method of manufacturing a semiconductor device, which has a step of selectively forming a silicide layer (9) on the impurity diffusion layer (7) in a region where the insulating film (6) has been removed, To be achieved.

[0009]

The operation will be described using the field effect transistor shown in FIG. 1 as an example. The same members as those shown in FIG. 2 are indicated by the same symbols.

By forming the insulating film 8 so as to cover the end portion of the element isolation insulating film 3 and forming the silicide layer 9,
Since the silicide layer 9 is formed apart from the end portion of the element isolation insulating film 3, it is possible to prevent additional stress from being applied to the semiconductor substrate 1 in the region in contact with the end portion of the element isolation insulating film 3 and to prevent crystal defects. Is suppressed, and an increase in leak current is suppressed.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A method for forming a silicide layer according to three embodiments of the present invention will be described below with reference to the drawings.

First Example See FIG. 3 A p-type silicon substrate 1 is formed by sequentially laminating a 200 Å thick silicon dioxide film (not shown) and a 1500 Å thick silicon nitride film 2, and patterning this to form an element. The element isolation insulating film 3 having a thickness of 4000 .ANG.

Referring to FIG. 4, the silicon nitride film 2 is removed, a 100 Å thick silicon dioxide film and a 1000 Å thick polycrystalline silicon film are sequentially formed on the entire surface, and the gate electrode 4 made of polycrystalline silicon is patterned. And a gate insulating film 5 made of silicon dioxide are formed. Next, a silicon dioxide film is formed on the entire surface and anisotropically etched to form a silicon dioxide film 6 on the side wall of the gate electrode 4. Next, arsenic impurities are ion-implanted with an implantation energy of 50 KeV and a dose amount of 4 × 10 ¹⁵ to form the source / drain 7.

Referring to FIG. 5, a silicon dioxide film 8 is formed to a thickness of about 500 Å, and is patterned to leave the source / drain 7 on the peripheral region in contact with the end portion of the element isolation insulating film 3 of the source / drain 7. Remove from above.

Referring to FIG. 6, titanium is sputtered to form a titanium film having a thickness of 500Å,
Heat treatment is performed at a temperature of 800 ° C. to react titanium with silicon, and a titanium silicide layer 9 is formed apart from the end of the element isolation insulating film 3.

Referring to FIG. 7, a PSG film 10 is formed as an interlayer insulating film with a thickness of 4000 Å.

Referring to FIG. 8, the PSG film 10 is patterned to form a contact hole 11 on the source / drain 7, an aluminum film is formed on the entire surface, and this is patterned to form a source / drain electrode 12.

Second Example A resist film is formed in place of the silicon dioxide film 8 formed in the first example, and the other steps are the same as in the first example. The resist film is to be removed after the titanium silicide layer 9 is formed.

Third Example See FIG. 9 A thin silicon dioxide film (not shown) having a thickness of 50 Å and a silicon nitride film 2 having a thickness of 1500 Å are sequentially formed on the p-type silicon substrate 1, and patterned to form an element. The element isolation insulating film 3 having a thickness of 4000 .ANG. Since the thickness of the silicon dioxide film underlying the silicon nitride film 2 is as thin as 50Å, the amount of oxygen supplied between the silicon nitride film 2 and the silicon substrate 1 is small and the bird's beak is small, and the element isolation insulating film 3 The shape of the end portion of is sharp as shown in the figure.

Referring to FIG. 10, after removing the silicon nitride film 2 and forming the gate electrode 4 and the gate insulating film 5 as in the first example, a silicon dioxide film is formed on the entire surface and anisotropically etched. A silicon dioxide film 6 is formed on the side wall of the gate electrode 4. At this time, since the shape of the edge of the element isolation insulating film 3 is steep, the silicon dioxide film 6 remains on the sidewall of this edge. Next, as in the first example, the impurity arsenic is ion-implanted to form the source / drain 7.

Referring to FIG. 11, titanium is sputtered to form a titanium film having a thickness of 500Å,
Heat treatment is performed at a temperature of 800 ° C. to react titanium with silicon to form a titanium silicide layer 9. Since the silicon dioxide film 6 is formed on the source / drain 7 in the region in contact with the end of the element isolation insulating film 3, the titanium silicide layer 9 is formed apart from the end of the element isolation insulating film 3. . The following steps are the same as those in the first example, and therefore will be omitted.

[0022]

As described above, in the semiconductor device and the method of manufacturing the same according to the present invention, the insulating film is formed on the peripheral region of the impurity diffusion layer in contact with the element isolation insulating film to selectively diffuse the impurities. By forming the silicide layer, the silicide layer is formed apart from the end of the element isolation insulating film, so that the leakage current due to the end of the element isolation insulating film can be suppressed and the device characteristics can be improved. Can be stabilized.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of the present invention.

FIG. 2 is an explanatory diagram of a conventional technique.

FIG. 3 is an explanatory view of the manufacturing process of the field effect transistor according to the present invention.

FIG. 4 is an explanatory view of the manufacturing process of the field effect transistor according to the present invention.

FIG. 5 is an explanatory view of the manufacturing process of the field effect transistor according to the present invention.

FIG. 6 is an explanatory view of the manufacturing process of the field effect transistor according to the present invention.

FIG. 7 is an explanatory view of the manufacturing process of the field effect transistor according to the present invention.

FIG. 8 is an explanatory view of the manufacturing process of the field effect transistor according to the present invention.

FIG. 9 is an explanatory view of the manufacturing process of the field effect transistor according to the present invention.

FIG. 10 is an explanatory view of the manufacturing process of the field effect transistor according to the present invention.

FIG. 11 is an explanatory view of the manufacturing process of the field effect transistor according to the present invention.

[Explanation of symbols]

 1 semiconductor substrate 2 silicon nitride film 3 element isolation insulating film 4 gate electrode 5 gate insulating film 6 insulating film 7 impurity diffusion layer (source / drain) 8 insulating film 9 silicide layer 10 PSG film 11 contact hole 12 source / drain electrode

Claims (3)

[Claims] 1. A semiconductor device in which a silicide layer (9) is formed on an impurity diffusion layer (7) formed in an element formation region on a semiconductor substrate (1), wherein the silicide layer (9) is an element. A semiconductor device, characterized in that it is formed so as to be separated from the end of the isolation insulating film (3). 2. An insulating film (8) is formed on a semiconductor substrate (1) having an element isolation insulating film (3) and an impurity diffusion layer (7) formed in an element forming region. (8) is patterned to remove the impurity diffusion layer (7) from above the impurity diffusion layer (7), leaving a peripheral region in contact with the end of the element isolation insulating film (3). A method of manufacturing a semiconductor device, comprising the step of selectively forming a silicide layer (9) on the impurity diffusion layer (7) in the region where (8) is removed. 3. The method for manufacturing a semiconductor device according to claim 2, further comprising the step of forming a resist film instead of forming the insulating film (8) and removing the resist film after forming the silicide layer (9). A method of manufacturing a semiconductor device, comprising: