JPH03192723A - Manufacture of semiconductor element - Google Patents

Abstract

PURPOSE:To enable an emitter region to be formed in self-aligned manner by a method wherein silicon carbide is selectively deposited only on the emitter part by the chemical vapor deposition process using silicon base gas, hydrocarbon gas and hydrogen chloride gas. CONSTITUTION:An emitter part 3-1 is formed in self-aligned manner by chemical vapor deposition process using silicon base gas, hydrocarbon gas and hydrogen chloride gas and later an emitter layer 4-3 is formed by doping the emitter part 3-1 using the ion-implantation process. That is, a silicon carbide can be deposited only on the silicon exposed part to be deposited using the mixed gas comprising the silicon base gas, the hydrocarbon gas and the hydrogen chloride gas. Through these procedures, the doped silicon carbide layer 3-1 can be selectively deposited thereby enabling the self-aligned emitter layer 4-3 to be formed.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a silicon hetero-bipolar transistor using silicon carbide as an emitter material, and particularly relates to a method for manufacturing a semiconductor device in which a silicon carbide emitter is formed in a self-aligned manner. .

(Prior Art) Conventionally, the emitter portion of a silicon hetero bipolar transistor using silicon carbide as a material for the hetero emitter has been manufactured as follows. The structure is an emitter top structure, and a collector portion and a base portion are first formed using the same manufacturing method as a normal silicon bipolar transistor. Thereafter, silicon carbide is deposited by chemical vapor deposition (CVD) using SiH4, C2H2, or the like as a raw material gas to produce an emitter.

(Problems to be Solved by the Invention) In these methods, silicon carbide is deposited over the entire surface of the substrate. Therefore, in order to fabricate the emitter portion, it is necessary to remove excess deposited silicon carbide.

In other words, such a removal process is required in producing an element. Furthermore, since silicon carbide is stable as a substance, the removal process itself is difficult. Furthermore, it is necessary to take into account alignment errors between photomasks during removal in transistor pattern design, making it difficult to manufacture fine transistors with good controllability.

An object of the present invention is to provide a method that does not require a silicon carbide removal step and can form silicon carbide in an emitter portion in a self-aligned manner.

(Means for solving the problem) When forming the emitter, silicon carbide is selectively deposited only on the emitter portion by using a chemical vapor deposition method using silicon gas, hydrocarbon gas, and hydrogen chloride gas. This makes it possible to omit the extra step of removing silicon carbide that was conventionally necessary. There are two possible doping methods for the emitter portion: 1) ion implantation, and 2) doping during emitter layer growth.

(Function) One of the reasons why it has not been possible to fabricate a silicon carbide emitter layer in a self-aligned manner is that silicon carbide could not be selectively grown. In the conventional CVD method using silicon-based gas and hydrocarbon-based gas as raw material gases, silicon carbide grows not only on the exposed silicon surface but also on the dielectric insulating film used as a mask material. .

This is considered to be due to the following reasons. In the conventional CVD method, it is conceivable that silicon is deposited on the dielectric insulating film as well as on the silicon. This can be inferred from the fact that a similar phenomenon is observed in normal silicon growth. In this way, silicon carbide is produced by the reaction between the deposited silicon and carbon atoms.

It is difficult for the silicon carbide thus generated and deposited on the film to be released into the gas phase. For this reason, it is not possible to obtain selectivity such as growing on a certain material but not growing on a certain material at all. On the other hand, as in the present invention, by mixing hydrogen chloride gas with silicon-based gas and hydrocarbon-based gas,
When performing the growth, it is possible to selectively grow silicon carbide only on the exposed portions of silicon. This is considered to be due to the fact that silicon atoms deposited on the -degree insulating film are removed by hydrogen chloride gas before bonding with carbon atoms. In other words, by using such a gas system and using a dielectric insulating film as a mask material, it becomes possible to selectively grow silicon carbide, which will become the emitter layer, on the already formed base layer. . Thereafter, an emitter layer is formed by doping impurities using an ion implantation method. Alternatively, when selectively growing silicon carbide using the gas system described above, for example,
By simultaneously using doping gases such as PH3°AsH3, B2H6, a doped silicon carbide layer can be selectively grown to form a self-aligned emitter layer.

(Example) Next, an example of the present invention will be described in detail with reference to the drawings.

Example 1 FIG. 2 is a schematic diagram showing an example of a semiconductor device manufacturing apparatus used in the method of the present invention.

The apparatus includes a reaction tube 1-1 for performing growth, a susceptor 1-2 for holding a substrate 1-3, a heating device 1-4 for heating the substrate 1-3 and the susceptor 1-2, and a cylinder. 1-5a.

1-5b, 1-5c, 1-5d, gas mixer 1-
6. Flow control device 1-7a, 1-7b, 1-7c,
1-7d, and an H2 gas purification device 1-8a.

FIGS. 1A to 1C are diagrams illustrating the present invention in detail, and are schematic cross-sectional views showing the manufacturing process of a silicon heterobipolar Tr of a silicon carbide emitter.

First, by thermal diffusion onto the p- silicon substrate 2-6, an n
+Collector electrode layer (2-1) was formed. Next, by using a reduced pressure chemical vapor phase method, an n-type collector layer (2-2) was formed on the substrate 2-6, and then the surface was thinly oxidized. On top of that, a nitride film is deposited by chemical vapor deposition, an isolation pattern is formed, and an isolation oxide film (
2-4) was grown. The base region (2-3) is prepared using conventional photolithography techniques as well as ion implantation.
was formed. Thereafter, an oxide film (200 nm thick) (2-5) was deposited using a chemical vapor deposition method, and an emitter hole was formed using an ordinary photolithography technique. Although an oxide film was used as a mask this time, similar results can be obtained with a nitride film. A configuration diagram of the substrate manufactured through the above steps is shown in FIG. 1(a). Silicon carbide was selectively grown on the substrate thus formed under the following conditions. The growth apparatus used was a normal reduced pressure vertical chemical vapor deposition apparatus as shown in FIG.

As raw material gas, 5iH2CI2 and 1-C4H
10 was used. H2 was used as a carrier gas.

In addition to these gases, HCI gas was used.

5iH2C12,1-C4H10, HCI and H2
The flow rates are respectively 10.5.120.6000cc/
It was min. Silicon carbide can be selectively grown to a thickness of 50 nm at a growth temperature of 900° C. and a growth time of 5 minutes, and a silicon carbide layer 3-1 can be formed in a self-aligned manner as shown in FIG. 1(b). Ta. Silicon may be deposited on silicon carbide layer 3-1 to facilitate contact with wiring. Thereafter, an emitter region was formed by performing ion implantation and then adding impurities to the silicon carbide layer by thermal diffusion. Finally, contact holes for the base and collector are made, AI is deposited, and a wiring pattern including the emitter electrode 4-3, base electrode 4-2, and collector electrode 4-1 is formed by AI photo-etching. , fabricated a silicon hetero bipolar transistor. The finally produced structure is shown in FIG. 1(c).

In this example, 5iH is used as the raw material gas for silicon.
2C12 was used, but other chlorosilane-based gases such as 5
A similar structure can be formed using iHC13, 5iC14, etc. Furthermore, although 1-C4H10 was used as the raw material gas for carbon this time, a similar structure can be obtained by using other hydrocarbon gases such as C3H5.

Example 2 An apparatus similar to that used in Example 1 was used. The device configuration is as described in detail in Example 1.

As the substrate, a substrate similar to that used in Example 1 was used. By the procedure described in Example 1, the structure shown in FIG. 1(a) was formed. Thereafter, silicon carbide was selectively grown by growing under the following conditions. SiH4 and C3HB were used as raw material gases. H2 was used as a carrier gas. In addition to these gases, HCI
It was used. SiH4, C3HB, HCI and H
The flow rates of 2 are respectively 10.2.90.6000cc/
It was min. Silicon carbide could be selectively grown to a thickness of 50 nm at a growth temperature of 1000° C. and a growth time of 10 minutes, and a structure similar to that shown in FIG. 1(b) explained in Example 1 was formed. After that, silicon may be deposited on the silicon carbide. Thereafter, an emitter region was formed by adding impurities to the silicon carbide layer by ion implantation and thermal diffusion. Finally, a contact hole between the base and the collector was formed, AI was deposited, and a wiring pattern was formed by AI photo-etching to fabricate a silicon hetero bipolar transistor. The finally produced structure is shown in FIG. 1(c).

In this example, SiH is used as the raw material gas for silicon.
4 was used, but a similar structure can be formed using other hydrogenated silane gases such as Si2H6. In addition, this time, as the raw material gas for carbon, C3
Although H8 was used, a similar structure can be obtained using other hydrocarbon gases such as 1-C4H10.

Example 3 An apparatus similar to that used in Example 1 was used. The device configuration is as described in detail in Example 1.

As the substrate, a substrate similar to that used in Example 1 was used. By the procedure described in Example 1, the structure shown in FIG. 1(a) was formed. Thereafter, silicon carbide was selectively grown by growing under the following conditions. 5iH2C12, C3HB was used as the raw material gas.

H2 was used as a carrier gas. In addition to these gases, HCI was used. 5iH2CI2. C3
H.B.

The HCI and H2(7) flow rates were 15.2.
It was 90°6000cc/min. growth temperature 100
Doped silicon carbide with 0'C growth time of 10 minutes
It was possible to selectively grow the film to a thickness of 0 nm, and a structure similar to that shown in FIG. 1(b) explained in Example 1 was formed.

After that, continuously with the formation of silicon carbide as a raw material gas, 5
iH2CI2°HCI, H2 was flowed to selectively deposit 50 nm of silicon on silicon carbide. In this example, silicon was selectively grown, but after silicon is deposited over the entire surface, excess silicon may be removed using photolithography. Alternatively, silicon may not be deposited. Thereafter, an emitter region was formed by adding impurities to the silicon carbide layer by ion implantation and thermal diffusion. Finally, contact holes for the base and collector were made, A1 was deposited, and a wiring pattern was formed by AI photo-etching to fabricate a silicon hetero bipolar transistor. The finally produced structure is shown in FIG. 1(e).

In this example, SiH is used as the raw material gas for silicon.
4 was used, but a similar structure can be formed using other chlorosilane-based gases such as 5iHC13.

In addition, this time, as a raw material gas for carbon raw material gas, C5H
Although g was used, a similar structure can be obtained by using other hydrocarbon gases such as 1-C4H10.

Example 4 An apparatus similar to that used in Example 1 was used. The device configuration is as described in detail in Example 1.

As the substrate, a substrate similar to that used in Example 1 was used. By the procedure described in Example 1, the structure shown in FIG. 1(a) was formed. Thereafter, silicon carbide was selectively grown by growing under the following conditions. SiH4 and C3HB were used as raw material gases. H2 was used as a carrier gas. In addition to these gases, HCI
It was used. Further, PH3 was used as a doping gas. Although PH3 was used here, other doping gases such as AsH3 may also be used. For example, SiH4,
The flow rates of C3HB, HCI, H2 and PH3 are:
10.2.90.6000.0.01cc/m respectively
It was in. Silicon carbide could be selectively grown to a thickness of 50 nm at a growth temperature of 1000° C. and a growth time of 10 minutes, and a structure similar to that shown in FIG. 1(b) explained in Example 1 was formed. Since doping is performed during silicon carbide growth, the emitter layer is formed through the above steps.

Doped silicon may then be deposited over the silicon carbide. Finally, a contact hole for the base and collector was formed, AI was deposited, and a wiring pattern was formed by AI photo-etching to fabricate a silicon hetero bipolar transistor. The finally produced structure is shown in FIG. 1(e).

In this example, SiH is used as the raw material gas for silicon.
4 was used, but a similar structure can be formed using other hydrogenated silane gases such as Si2H6. In addition, this time, as the raw material gas for carbon, C3
Although H8 was used, a similar structure can be obtained using other hydrocarbon gases such as 1-C4H10.

(Effects of the Invention) As described above in detail, according to the method of the present invention, when manufacturing a silicon hetero-bipolar transistor using silicon carbide as an emitter material, silicon carbide is selectively grown to form an emitter region in a self-aligned manner. can be formed.

[Brief explanation of drawings]

FIGS. 1(a) to 1(c) are schematic cross-sectional views showing the manufacturing process of a silicon carbide emitter heterobipolar transistor according to an embodiment of the present invention. 2-1... Embedded layer for collector electrode, 2-2...
Collector layer, 2-3...Base layer, 2-4...Isolation oxide film, 2-5...Oxide film, 2-6...Substrate. FIG. 2 is a schematic configuration diagram showing an example of a semiconductor device manufacturing apparatus used in the method of the present invention. 1-1... Reaction tube for performing growth, 1-2... Substrate 1
- Susceptor for holding 3, 1.3...Substrate, 1
．． 4... Heating device that heats the substrate 1-3 and the susceptor 1.2, 1-5a, 1-5b, 1-5c, 1
-5d-...Cylinder, 1-6...Gas mixer, 1-
7a, 1-7b, 1-7c, 1-7d...flow control device, 1-8...H2 gas purification device.

Claims (2)

[Claims] (1) In a method for manufacturing a semiconductor device using silicon carbide as an emitter material, the emitter portion is manufactured in a self-aligned manner by chemical vapor deposition using silicon-based gas, hydrocarbon-based gas, and hydrogen chloride gas, and then A method of manufacturing a semiconductor device characterized by doping an emitter portion by ion implantation to form an emitter layer. (2) In a method for manufacturing a semiconductor device using silicon carbide as an emitter material, an emitter layer is produced in a self-aligned manner by chemical vapor deposition using silicon-based gas, hydrocarbon-based gas, hydrogen chloride gas, and doping gas. A method for manufacturing a semiconductor device characterized by: