JPH05226349A - Semiconductor device and manufacturing method thereof - Google Patents

Abstract

(57) [Summary] [Object] To provide a semiconductor device having a simple process, capable of reducing manufacturing cost, and easily miniaturized, and a manufacturing method thereof. [Structure] The first silicon oxide film 26 is isotropically etched to form an opening 28a. The emitter 3 is epitaxially grown in the opening 28a. When boron ions are implanted, the thick portion T is hardly implanted into the silicon substrate 2, and the thin portion S is largely implanted. Also, regarding the part covered with the emitter 3,
Although implanted into the silicon substrate 2, compared with the portion S having a small film thickness, the implanted concentration is thin and the depth from the substrate surface is shallow due to the amount trapped by the emitter 3.
As a result, the base 4 having a small layer thickness and the P ⁺ -type external base 5 can be easily formed (FIG. 9A). [Effect] A mask for forming the base 4 and the external base 5 is not necessary, and an alignment margin is not expected in the manufacturing process.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device structure and its manufacture, and more particularly to simplification of the manufacturing process.

[0002]

2. Description of the Related Art A conventional method for manufacturing a transistor 1 is shown in FIG.
Shown in. First, a photoresist 6a is applied to the surface of the N-type silicon substrate 2 and patterned to form an opening 8a. Boron ions, which are P-type impurities, are implanted into the opening 8a and the entire surface of the photoresist 6a. As a result, the P-type base 4 is formed (FIG. 9A). Next, the photoresist 6a shown in FIG.
A photoresist 6b is newly applied to the surface of the silicon substrate 2 and patterned as shown in FIG. 1A to form an opening 8b. Phosphorus ions, which are N-type impurities, are implanted into the opening 8b and the entire surface of the photoresist 6b. As a result, the N-type emitter 3 is formed inside the P-type base 4 (a in the figure).

Next, the photoresist 6b shown in FIG. 1B is removed, a photoresist 6c is newly applied to the surface of the silicon substrate 2, and patterning is performed as shown in FIG. 1C to form an opening 8c. Opening 8c and photoresist 6
Implant boron ions on the entire surface of c. As a result, the external base 5 having a higher impurity concentration than the base 4 formed in FIG.
Are formed (Fig. 3C).

Next, the photoresist 6c is removed, and a silicon oxide film 14 is formed on the surface of the silicon substrate 2 by low pressure chemical vapor deposition (LPCVD). After that, a photoresist is applied and patterned to form a silicon oxide film 14
Etching is performed. Then, a contact hole 8d is formed to form electrodes for the emitter 3 and the base 4 (FIG. 8D). Polysilicon 10a, 10b, 10c for forming electrodes is formed in the formed contact hole 8d. The base electrodes 13a and 13c and the emitter electrode 13b are formed of aluminum. Form the collector electrode 12 of platinum on the back surface of the silicon substrate 2,
Transistor 1 is completed (figure E).

[0005]

However, the method of manufacturing the transistor 1 as described above has the following problems. Base 4, Emitter 3, and External Base 5
The photoresist formation process was required three times in total in the formation process. Therefore, the process was complicated. In addition, it is necessary to consider the alignment margin for three times, which makes it difficult to miniaturize.

The present invention solves the above problems, simplifies the process, reduces the manufacturing cost, and facilitates miniaturization without the need for an alignment margin, and the manufacturing thereof. The purpose is to provide a method.

[0007]

According to a first aspect of the present invention, there is provided a method of manufacturing a semiconductor device, comprising a first region forming step of forming a first region of a first conductivity type so as to project from a surface of a semiconductor substrate, and the first region. A second region forming step of forming a second region of the second conductivity type by performing ion implantation from above.

According to a second aspect of the present invention, there is provided a method of manufacturing a semiconductor device, comprising: a first step of forming an insulating film on a semiconductor substrate; a part of the insulating film is removed by etching; A second step of forming a protruding first region of the first conductivity type and forming an efficient transmission part near the boundary between the insulating film and the first region, where the efficiency of ion implantation into the semiconductor substrate is higher than that of the surroundings; By performing ion implantation on the semiconductor substrate from above the first region,
And a third step of forming a second region of the second conductivity type.

In the method of manufacturing a semiconductor device according to a third aspect, isotropic etching is further used for etching for removing a part of the insulating film in the second step, and
Regarding the formation of the efficient transmission portion, the first region is formed in the portion removed by the etching process so as to slightly overlap or not overlap with the insulating film.

According to another aspect of the semiconductor device of the present invention, the first region is provided so as to project from the surface of the semiconductor substrate, and the insulating film has a small film thickness in the vicinity of the boundary with the first region. It is characterized in that it is formed so as to have a thick film thickness.

According to a fifth aspect of the semiconductor device, the thin film portion of the insulating film near the boundary between the insulating film and the first region further comprises:
It is characterized by being formed by isotropic etching.

[0012]

According to the first aspect of the present invention, there is provided a method of manufacturing a semiconductor device, comprising a first region forming step of forming a first region of a first conductivity type so as to project from a surface of a semiconductor substrate, and ion implantation from above the first region. The method is characterized by including a second region forming step of forming a second region of the second conductivity type.
Therefore, when ion implantation is performed from above the first region, the first region can be used in a self-aligned manner.

According to a second aspect of the present invention, there is provided a method of manufacturing a semiconductor device, comprising: a first step of forming an insulating film on a semiconductor substrate; a part of the insulating film is removed by etching; A second step of forming a protruding first region of the first conductivity type and forming an efficient transmission part near the boundary between the insulating film and the first region, where the efficiency of ion implantation into the semiconductor substrate is higher than that of the surroundings; By performing ion implantation on the semiconductor substrate from above the first region,
A third step of forming a second region of the second conductivity type is provided.

Therefore, when the ion implantation is performed from above the first region, the first region can be used in a self-aligned manner, and the low concentration layer having a small layer thickness and the low concentration layer are formed so as to be sandwiched therebetween. The second region formed of the high-concentration layer having a large layer thickness can be easily obtained.

In the method of manufacturing a semiconductor device according to a third aspect, isotropic etching is further used for the etching for removing a part of the insulating film in the second step, and
Regarding the formation of the efficient transmission portion, the first region is formed in the portion removed by the etching process so as to slightly overlap or not overlap with the insulating film. Therefore, the formation of the efficient transmission part becomes easy.

According to another aspect of the semiconductor device of the present invention, the first region is provided so as to project from the surface of the semiconductor substrate, and the insulating film has a small film thickness in the vicinity of the boundary with the first region. It is characterized in that it is formed so as to have a thick film thickness. Therefore, when ion implantation is performed from above the first region, the first region can be used in a self-aligned manner, and the vicinity of the boundary between the insulating film and the first region can be covered with the second region and the insulating film. Ion implantation can be performed more efficiently than the broken portion.

According to a fifth aspect of the semiconductor device, the thin film portion of the insulating film near the boundary between the insulating film and the first region further comprises:
It is characterized by being formed by isotropic etching.
Therefore, the formation of the efficient transmission part becomes easy.

[0018]

An embodiment of the present invention will be described with reference to the drawings. First, as shown in FIG. 2A, a first silicon oxide film 26, which is an insulating film, is formed on the surface of the N-type silicon substrate 2. In this example, low pressure chemical vapor deposition (LPCVD) was used, and it was formed by thermal decomposition with SiH ₄ and N ₂ O at 800 ° C. Photoresist using mask for emitter formation 29
Pattern (a in the figure). Isotropic etching is performed using hydrofluoric acid (FIG. 3C) to form an opening 28a (FIG. 3D), and the photoresist 29 is removed.

Next, as shown in FIG. 1A, the opening 28a is formed.
An emitter 3 which is a first region of the first conductivity type is formed so as to project from the silicon substrate 2. In this embodiment,
Supply SiH ₂ Cl ₂ and H ₂ and PH ₃ as dopant,
The N type emitter 3 was formed by epitaxial growth at a temperature of ° C.

In the present embodiment, the epitaxial growth was stopped when the emitter 3 contacted the first silicon oxide film 26, but the emitter 3 slightly overlaps the first silicon oxide film 26 or You may stop at the stage of growing so that they do not overlap.

Next, boron ions are implanted into the entire surface of the emitter 3 and the first silicon oxide film 26. The implanted boron ions are trapped in the first silicon oxide film 26 in the portion T where the first silicon oxide film 26 is thick, and are hardly implanted into the silicon substrate 2. On the other hand, for the portion S having a small film thickness, which is the efficient transmission portion,
Since it is not trapped in the first silicon oxide film 26, a large amount of boron ions are implanted. The portion covered with the emitter 3 is injected into the silicon substrate 2 while being trapped by the emitter 3. However, the thin portion S
Compared with the above, the concentration to be injected is thin and the depth from the substrate surface is also shallow due to the amount trapped by the emitter 3.

As a result, P, which is a low-concentration layer having a small layer thickness, is formed.
P ⁺ type external base 5 which is a thick high-concentration layer formed so as to sandwich the base 4 and the low-concentration layer.
Can be easily formed (Fig. 1A). Thus, in this embodiment, the P-type base 4 and the P ⁺ -type external base 5 form the second region of the second conductivity type.

As described above, in this embodiment, the emitter 3 can be used in a self-aligned manner in forming the P-type base 4 and the P ⁺ -type external base 5. Therefore, a mask for forming the base 4 and the external base 5 becomes unnecessary. Thereby, it is not necessary to consider the alignment margin in the manufacturing process, and the miniaturization is facilitated.

Further, the portion S where the thickness of the first silicon oxide film 26 is thin is formed such that the thickness is thin near the boundary with the emitter 3 and becomes thicker as it goes away. Therefore, by implanting boron ions, the base 4 and the P ⁺ -type external base 5 can be easily formed.

It should be noted, the implanted boron ions are to be trapped by the emitter 3, affecting the N ⁺ concentration of the emitter 3. Therefore, in consideration of this, the emitter 3 may be formed with a sufficient N ⁺ concentration.

After that, the implanted boron is activated by annealing and then thermally decomposed with SiH ₄ and N ₂ O at 800 ° C.
A silicon oxide film 27 is formed (Fig. 3C). Contact holes 20 are formed to form electrodes for the emitter 3 and the base 4. Polysilicon 10a, 10b, 10c for forming electrodes is formed in the formed contact hole 20. The base electrodes 13a and 13c and the emitter electrode 13b are formed of aluminum. The collector electrode 12 is formed of platinum on the back surface of the silicon substrate 2 to complete the transistor 21.

In this embodiment, the emitter 3 is formed by epitaxial growth, but CV
It may be formed by the D method. In this case, the emitter 3 is made of polycrystalline silicon.

Further, in the present embodiment, the formation of the efficient transmission portion is carried out by isotropically etching the first silicon oxide film 26. However, any material may be used as long as it can be formed in the vicinity of the boundary between the first silicon oxide film 26 and the emitter 3 so that the ion implantation efficiency into the semiconductor substrate is higher than that in the surroundings. For example, as shown in FIG. like,
The efficient transmission part may be formed so that the first silicon oxide film 26 and the emitter 3 do not slightly overlap each other. Alternatively, the emitter 3 may be formed to have a thin end portion as shown in FIG. 9A, and the first silicon oxide film 26 may be formed as shown in FIG.
May be formed so as to be thin.

In this embodiment, the npn transistor has been explained, but it may be adopted as a pnp transistor.

[0030]

According to the first aspect of the present invention, there is provided a method of manufacturing a semiconductor device, comprising a first region forming step of forming a first region of a first conductivity type so as to project from a surface of a semiconductor substrate, and ions are formed from above the first region. By performing the injection, the second conductivity type second
A second region forming step of forming a region is provided. Therefore, when the ion implantation is performed from above the first region, the first region can be used in a self-aligned manner,
The number of masks can be reduced. As a result, the process is simple and the manufacturing cost can be reduced. Furthermore, it is not necessary to consider the alignment margin in the manufacturing process, and it is possible to provide a semiconductor device that can be easily miniaturized.

According to a second aspect of the present invention, there is provided a method of manufacturing a semiconductor device, comprising: a first step of forming an insulating film on a semiconductor substrate; a part of the insulating film is removed by etching; A second step of forming a protruding first region of the first conductivity type and forming an efficient transmission part near the boundary between the insulating film and the first region, where the efficiency of ion implantation into the semiconductor substrate is higher than that of the surroundings; By performing ion implantation on the semiconductor substrate from above the first region,
A third step of forming a second region of the second conductivity type is provided.

Therefore, when the ion implantation is performed from above the first region, the first region can be used in a self-aligned manner, and the low concentration layer having a small layer thickness and the low concentration layer are formed so as to be sandwiched therebetween. The second region formed of the high-concentration layer having a large layer thickness can be easily obtained. As a result, the number of masks can be reduced, the process can be simplified, and the manufacturing cost can be reduced. Furthermore, it is not necessary to consider the alignment margin in the manufacturing process, and it is possible to provide a semiconductor device that can be easily miniaturized.

In the method for manufacturing a semiconductor device according to a third aspect, isotropic etching is further used for etching for removing a part of the insulating film in the second step, and
Regarding the formation of the efficient transmission portion, the first region is formed in the portion removed by the etching process so as to slightly overlap or not overlap with the insulating film. Therefore, the formation of the efficient transmission part becomes easy. This reduces the number of masks, simplifies the process,
Manufacturing costs can be reduced. Furthermore, it is not necessary to consider the alignment margin in the manufacturing process, and it is possible to provide a semiconductor device that can be easily miniaturized.

According to another aspect of the semiconductor device of the present invention, the first region is provided so as to protrude from the surface of the semiconductor substrate, and the insulating film has a small film thickness near the boundary with the first region and is separated away. It is characterized in that it is formed so as to have a thick film thickness. Therefore, when ion implantation is performed from above the first region, the first region can be used in a self-aligned manner, and the vicinity of the boundary between the insulating film and the first region can be covered with the second region and the insulating film. Ion implantation can be performed more efficiently than the broken portion.

As a result, the number of masks can be reduced, the process can be simplified, and the manufacturing cost can be reduced. Further, this can reduce the number of masks, simplify the process, and reduce the manufacturing cost. Furthermore, it is not necessary to consider the alignment margin in the manufacturing process, and it is possible to provide a semiconductor device that can be easily miniaturized.

According to a fifth aspect of the semiconductor device, the thin film portion of the insulating film near the boundary between the insulating film and the first region further comprises:
It is characterized by being formed by isotropic etching.
Therefore, the formation of the efficient transmission part becomes easy. As a result, the number of masks can be reduced. Furthermore, it is not necessary to consider the alignment margin in the manufacturing process, and it is possible to provide a semiconductor device that can be easily miniaturized.

[Brief description of drawings]

FIG. 1 is a diagram showing a manufacturing process of a transistor 21.

FIG. 2 is a diagram showing a process of forming an opening portion 28a by isotropic etching in a manufacturing process of the transistor 21.

FIG. 3 is a diagram showing an example of a shape of an efficient transmission part of a transistor 21.

FIG. 4 is a diagram showing a manufacturing process of a conventional transistor 1.

[Explanation of symbols]

 2 ... Silicon substrate 3 ... Emitter 4 ... Base 5 ... External base 26 ... First silicon oxide film

Claims (5)

[Claims] 1. A first step of forming a first region of a first conductivity type so as to project from a surface of a semiconductor substrate, and by performing ion implantation from above the first region,
A second step of forming a second region of the second conductivity type in the semiconductor substrate, and a method for manufacturing a semiconductor device. 2. A first step of forming an insulating film on a semiconductor substrate, a part of the insulating film is removed by etching, and the removed part has a first conductivity type first region protruding from the surface of the semiconductor substrate. And forming an efficient transmission part near the boundary between the insulating film and the first region in which the efficiency of ion implantation into the semiconductor substrate is higher than the surroundings. From above the first region to above the semiconductor substrate. A third step of forming a second region of the second conductivity type by implanting ions into the semiconductor device, the method of manufacturing a semiconductor device. 3. The method of manufacturing a semiconductor device according to claim 2, wherein isotropic etching is used for etching for removing a part of the insulating film in the second step, and etching is performed for forming the efficient transmission portion. A method of manufacturing a semiconductor device, wherein the first region is formed in the removed portion so as to slightly overlap or not overlap with the insulating film. 4. A semiconductor substrate, a second-conductivity-type semiconductor substrate having a thin high-concentration layer formed so as to sandwich the low-concentration layer and a low-concentration layer formed in the semiconductor substrate. The second region, the first region of the first conductivity type provided above the second region, the semiconductor substrate surface, the insulating film that covers the first region and the second region, and the high concentration layer of the second region are connected. In the semiconductor device including the electrode for the second region, the first region is provided so as to project from the surface of the semiconductor substrate, and the insulating film has a thin film thickness in the vicinity of the boundary with the first region. ,
A semiconductor device, characterized in that the film is formed so that the film thickness becomes thicker as it is farther away. 5. The semiconductor device according to claim 4, wherein the thin film portion of the insulating film near the boundary between the insulating film and the first region is formed by isotropic etching.