JP2003203867A - Vapor growth method and vapor growth apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vapor growth method and a vapor growth apparatus which can prevent adhesion of polysilicon to the inside of the vapor growth apparatus. <P>SOLUTION: The vapor growth apparatus 100 comprises a reaction vessel 101, a raw material gas supply port 107 and a purge gas supply port 111, to supply a purge gas PG2 including the hydrogen chloride gas. While a silicon thin film is formed with the vapor growth method on a single-crystal substrate W by supplying a raw material gas SG to a silicon single-crystal substrate W from the raw material gas supply port 107, the purge gas PG2, including the hydrogen chloride gas, is supplied to the purge gas supply region 120 from the purge gas supply port 111. Accordingly, adhesion of polysilicon in the purge gas supply region 120 can be prevented. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for vapor phase growing a silicon thin film on a silicon single crystal substrate and a vapor phase growth apparatus used for the method.

[0002]

_2. Description of the Related Art Monosilane (SiH ₄ ), dichlorosilane (SiH ₂ Cl ₂ ), trichlorosilane (SiHCl ₃ ), and tetrasilane (SiHCl ₃ ) on a heated silicon single crystal substrate together with a carrier gas such as hydrogen (H ₂ ) gas. Silicon chloride (SiC
silane-based source gas such as l ₄ ) and phosphine (P
H ₃ ), diborane (B ₂ H ₆ ) and other dopant gases are supplied to vapor-deposit a silicon single crystal thin film.
It is better known than before. Such a vapor phase growth method is usually performed by a general vapor phase growth apparatus.

By the way, using a conventional vapor phase growth apparatus,
When vapor-phase growth of a silicon single-crystal thin film is performed on the main surface of a silicon single-crystal substrate placed on a susceptor, polysilicon adheres to the inside of the reaction vessel of the vapor-phase growth apparatus during vapor-phase growth. The deposition of polysilicon is most remarkable on the susceptor 102 arranged in the reaction vessel 101, which is shown in the schematic view of the vapor phase growth apparatus 100 in FIG. Polysilicon adheres to the main front surface 102a and the main back surface 102b of the susceptor 102 excluding the mounting position of the silicon single crystal substrate W. Polysilicon also adheres to a quartz member such as the susceptor support member 104 arranged on the main back surface 102b side of the susceptor.

[0004]

Conventionally, the polysilicon deposited in the reaction vessel has been conventionally treated by the reaction vessel 10 after completion of vapor phase growth.
1 is removed by introducing an etching gas containing hydrogen chloride (HCl) gas. The etching gas is supplied from the side of the main surface 102a of the susceptor where the attached polysilicon is likely to affect the vapor phase growth of the silicon single crystal thin film, and therefore the polysilicon attached to the side of the main back surface 102b of the susceptor cannot be completely removed. Tend to remain.
When the next vapor phase growth is performed with the polysilicon attached to the main back surface 102b side of the susceptor, the polysilicon is released and flies to the main back surface 102a side of the susceptor and adheres to the surface of the silicon single crystal thin film. A silicon single crystal thin film with a large number of particles is formed. Further, when the polysilicon is etched by hydrogen supplied as a purge gas, the dopant contained in the polysilicon is also released, so that the resistivity of the formed silicon single crystal thin film becomes unstable. Therefore, the susceptor support 10 arranged on the main back surface 102b side of the susceptor before the number of particles and the resistivity of the silicon single crystal thin film reach a level at which problems occur.
The quartz member such as No. 4 is removed from the apparatus and immersed in a mixed solution of hydrofluoric acid and nitric acid to wet-etch the polysilicon. Since the silicon single crystal thin film cannot be grown during this wet etching, and during the time when the quartz member is removed from the apparatus or mounted again, there is a problem that the operation rate of the apparatus is lowered.

If the polysilicon attached to the quartz member such as the susceptor support 104 is removed by dry etching using a gas containing hydrogen chloride, or wet etching using a mixed solution of hydrofluoric acid and nitric acid, the surface of the quartz member will be removed. It is observed that the surface is roughened due to scraping. Then, if the removal of the polysilicon attached to the quartz member is repeated, the erosion of quartz further progresses.
There is a problem that the life of the quartz member is shortened.

The present invention has been made in order to solve the above problems, and vapor phase growth capable of preventing polysilicon from adhering to a region such as the main back surface of a susceptor where it is difficult to remove polysilicon. An object is to provide a method and a vapor phase growth apparatus.

[0007]

[Means for Solving the Problems and Actions / Effects] The vapor phase growth method of the present invention for solving the above problems involves contacting a source gas with the main surface of a silicon single crystal substrate placed in a reaction vessel. A purge gas containing hydrogen chloride gas is supplied into the reaction vessel while growing a silicon thin film on the silicon single crystal substrate.

Further, the vapor phase growth apparatus of the present invention for realizing the above method comprises a reaction vessel, a source gas supply port for supplying a source gas onto a silicon single crystal substrate arranged in the reaction vessel, A purge gas supply port for supplying a purge gas containing hydrogen chloride gas into the reaction vessel.

During the vapor phase growth, if a purge gas is supplied to the main back surface of the susceptor where it is difficult to remove polysilicon, the adhesion of polysilicon can be suppressed. However, since the source gas is not completely separated from the region to which the source gas is mainly supplied, the source gas also intrudes into the region to which the purge gas is supplied to some extent, and as a result, polysilicon is attached. Therefore, the present inventor tried to change the way of thinking in order to find a method in which the polysilicon does not adhere even if the source gas enters the region to which the purge gas is supplied. Then, in order to suppress the deposition of polysilicon, hydrogen chloride (HCl) gas is contained in the purge gas supplied into the reaction vessel during the vapor phase growth, so that the purge gas containing the hydrogen chloride gas is supplied. In the region, the inventors have found that the adhesion of polysilicon can be prevented, and have completed the present invention.

According to the present invention, even if the source gas invades a region where it is difficult to remove polysilicon, such as the main back surface of the susceptor, the purge gas containing hydrogen chloride gas is supplied to the region so that the polysilicon is removed. Can be prevented from adhering. This is because the purge gas, which has been conventionally used to suppress the invasion of the source gas, has a function of preventing a chemical reaction from the source gas to the polysilicon. Specifically, by including hydrogen chloride gas in the purge gas,
The above action can be imparted. As a result, in the region where the purge gas containing hydrogen chloride gas is supplied in the reaction container, the polysilicon does not adhere to the quartz member, so that wet etching for removing the polysilicon does not have to be frequently performed. As a result, the operating rate of the vapor phase growth apparatus can be increased.
Further, since the raw material gas can be allowed to enter the region to which the purge gas is supplied, the total flow rate of the purge gas used can be reduced.

In the vapor phase growth method of the present invention, the source gas is mainly supplied to the inner region of the reaction vessel so that the source gas is brought into contact with the silicon single crystal substrate during the growth of the silicon thin film. It has an area | region and the purge gas supply area | region where the purge gas is mainly supplied, and the purge gas containing hydrogen chloride gas can be supplied to the purge gas supply area. In the case of a vapor phase growth apparatus using a susceptor, the inside of the reaction vessel is a source gas supply region where the source gas is mainly supplied,
It can be distinguished from the purge gas supply region where the purge gas is mainly supplied. Since a temperature sensor, a heating device, a susceptor holder, and the like are arranged in the purge gas supply region, it is a region where deposition of polysilicon due to invasion of raw material gas is not desired. However, since the source gas supply region and the purge gas supply region cannot be completely separated, part of the source gas is supplied to the purge gas supply region and part of the purge gas is supplied to the source gas supply region. In the present invention,
By including hydrogen chloride gas in the purge gas supplied to the purge gas supply region, it is possible to prevent polysilicon from adhering to the members arranged in the purge gas supply region.

More specifically, the silicon single crystal substrate is
The purge gas, which is held by the susceptor arranged in the reaction vessel and contains hydrogen chloride gas, may be supplied to the quartz member adjacent to the susceptor. In the quartz member, polysilicon easily adheres to a portion adjacent to the susceptor, such as a connecting portion with the susceptor. As described above, when the polysilicon once attached to the quartz member is removed by etching, the surface of the quartz member becomes rough. This is considered to be because, when the polysilicon adheres to the quartz, cracks are easily generated on the surface of the quartz member due to the difference in coefficient of thermal expansion between the polysilicon and the quartz, and the quartz is easily separated. Therefore, a purge gas containing hydrogen chloride gas is supplied to the quartz member to prevent polysilicon from adhering to the quartz member. Then, as a result of preventing the adhesion of the polysilicon to the quartz member, the surface of the quartz member is not roughened, and the life of the quartz member is extended.

The present invention is carried out after vapor phase growth,
Unlike dry etching or wet etching, it is not intended to remove the polysilicon once attached to each part in the reaction vessel, but to prevent the adhesion of polysilicon in the purge gas supply region, hydrogen chloride is added. A purge gas containing gas is supplied. That is, during the vapor phase growth, the hydrogen chloride gas is allowed to exist in the purge gas supply region in advance, so that the reaction to polysilicon is prevented from the viewpoint of chemical equilibrium. Such an action is not present in the action of the conventional purge gas, and is completely different from the action of removing the already-attached polysilicon like the hydrogen chloride gas used for the gas etching described above. is there. The purge gas containing hydrogen chloride gas according to the present invention contains hydrogen chloride gas in an amount capable of preventing deposition of polysilicon. Incidentally, the present invention is also effective when using a raw material gas containing no chlorine such as monosilane gas, dichlorosilane,
When a gas containing chlorine such as trichlorosilane or silicon tetrachloride is used, the reaction from the source gas to polysilicon is
Since it can be prevented by the presence of hydrogen chloride gas, its effect is particularly exerted.

Further, the silicon single crystal substrate is held on the main surface side of the plate-like susceptor arranged in the reaction vessel, and the source gas supply region is on the main surface side of the susceptor holding the silicon single crystal substrate. The purge gas supply region may be formed on the main back surface side of the susceptor.
As described above, the adhesion of polysilicon is a problem on the main back surface side of the susceptor where it is difficult to remove polysilicon. Therefore, it is convenient to supply the purge gas containing hydrogen chloride gas to the region because, for example, the adhesion of polysilicon to the main back surface of the quartz member and the susceptor can be prevented.

Usually, in a vapor phase growth apparatus having a susceptor, vapor phase growth is performed while rotating the susceptor in order to grow a uniform thin film. The rotation drive unit that drives the susceptor to rotate may be made of, for example, a metal member or the like, which may cause a failure. Therefore, contact with corrosive gas is not preferable. Therefore, the purge gas is supplied to the rotation drive unit for the purpose of preventing contact with the corrosive gas generated by vapor phase growth and the source gas. However,
When the purge gas containing hydrogen chloride gas is supplied to the purge gas supply region, since hydrogen chloride gas is also a corrosive gas,
It is preferable to supply the purge gas containing hydrogen chloride gas without contacting the rotation drive unit of the susceptor. Further, hydrogen chloride gas is not included in the purge gas for purging the rotation drive unit.

[0016]

DETAILED DESCRIPTION OF THE INVENTION Referring to the accompanying drawings,
An embodiment of the present invention will be described. In this embodiment, the case of vapor-depositing a silicon single crystal thin film on a silicon single crystal substrate is shown, but the silicon thin film is not necessarily limited to a single crystal.

FIG. 1 is a schematic view showing an example of a vapor phase growth apparatus 100 used in the vapor phase growth method of the present invention. The vapor phase growth apparatus 100 includes a reaction vessel 101 and a source gas supply port 1 for supplying a source gas SG onto a silicon single crystal substrate W.
07 and a purge gas supply port 111 for supplying the purge gas PG2 containing hydrogen chloride gas into the reaction vessel 101. As a result, in the reaction vessel 101, the adhesion of polysilicon can be prevented in the region to which the purge gas PG2 containing hydrogen chloride gas is supplied.

Further, a raw material gas supply region 110 to which the raw material gas SG is mainly supplied is formed on the main surface 102a side of the susceptor 102 holding the silicon single crystal substrate W, and a main back surface 102b side of the susceptor 102 is formed. A purge gas supply region 120 to which the purge gas is mainly supplied is formed. The purge gas supply port 111 that supplies the purge gas PG2 containing hydrogen chloride gas is connected to the purge gas supply region 120. In the vapor phase growth apparatus 100 having the susceptor 102, the source gas SG wraps around to the main back surface 102b side of the susceptor 102,
Supporter 104 arranged on the main back surface 102b of the
Polysilicon tends to adhere to (particularly the connecting portion 104a with the susceptor 102) and the main back surface 102b of the susceptor 102. Therefore, the purge gas of the present invention is supplied to the region on the main back surface 102b side of the susceptor 102. Further, the threshold member 108 is arranged so that the raw material gas SG is less likely to enter the purge gas supply area 120 from the raw material gas supply area 110. The susceptor 102 is heated by the infrared heating lamp 103 arranged so as to face the susceptor 102 to heat the silicon single crystal substrate W, and the silicon single crystal substrate W is heated.
The source gas SG contacting with forms a silicon single crystal thin film.

Further, the vapor phase growth apparatus 100 has a quartz member adjacent to the susceptor 102. The quartz member is, for example, the susceptor support 1 for holding the susceptor 102.
Can be 04. Further, in the present embodiment, the susceptor support member 104 also serves as a protective cover for the temperature sensor 114 for detecting the temperature of the susceptor 102. The purge gas supply port 111 supplies the purge gas PG2 containing hydrogen chloride gas to the susceptor support 104.

Further, in the vapor phase growth apparatus 100 of this embodiment, the rotary drive unit 105 of the susceptor 102 and the rotary drive system purge gas supply port for supplying the rotary drive system purge gas PG1 for purging the rotary drive unit 105. 112
And further. Rotational drive unit 105 and susceptor 10
A rotary shaft is attached between the two main back surfaces 102b along the central axis O of the susceptor 102. In the present embodiment, the susceptor support tool 104 also serves as the rotation shaft. The rotational drive force is transmitted from the rotational drive unit 105 to the susceptor 102 via the susceptor support 104, and the susceptor 102 is rotationally driven. Such a rotation drive unit 105
Is composed of, for example, a metal member, and the source gas S
There is also a risk of failure due to contact with G or corrosive gas generated by the vapor phase growth reaction. Therefore, in order to prevent contact of these gases, the rotary drive system purge gas supply port 11
2, the rotary drive system purge gas PG1 is supplied.

When the rotary drive system purge gas PG1 is a purge gas containing hydrogen chloride gas according to the present invention, the hydrogen chloride gas, which is a corrosive gas, may damage the rotary drive unit 105, or the metal member forming the rotary drive unit may be damaged. As a result of being corroded, it causes metal contamination, which is not preferable. Therefore, it is preferable that the rotary drive system purge gas PG1 does not contain hydrogen chloride gas.

Further, the rotary drive system purge gas supply port 112
Is for supplying the rotary drive system purge gas PG1 to the purge gas supply region 120 along the susceptor support 104 as a rotary shaft that connects the susceptor 102 and the rotary drive unit 105. The purge gas supply port 111 is a susceptor. The purge gas PG2 containing hydrogen chloride gas can be supplied to the purge gas supply region 120 along the main back surface 102b of the 102. Rotational drive unit 105 and susceptor 10
By supplying the rotary drive system purge gas PG1 along the susceptor support tool 104 that connects the susceptor support tool 2 and the susceptor support tool 104, the inflow of the raw material gas SG and the corrosive gas into the vicinity of the susceptor support tool 104 is reduced and the susceptor support tool is also provided. 104
It is possible to suppress the adhesion of polysilicon to the outer periphery of the. Further, by supplying the purge gas PG2 containing hydrogen chloride gas along the main back surface 102b of the susceptor 102, it is possible to prevent the deposition of polysilicon on the main back surface 102b of the susceptor 102. Also, the susceptor support 104
Since the purge gas PG2 containing hydrogen chloride gas can also be directly supplied to the connecting portion 104a with the susceptor 102, it is possible to prevent the polysilicon from adhering to the connecting portion 104a.

At the first end 101a of the reaction vessel 101,
A raw material gas supply port 107 for supplying the raw material gas SG into the reaction vessel 101 is formed.
A gas discharge port 109 for discharging the gas in the reaction container 101 is formed at the second end 101b of the. The source gas SG is supplied from the side of the first end 101a of the reaction vessel 101 along the side of the main surface 102a of the susceptor 102, and is discharged to the side of the second end 101b of the reaction vessel 101. The purge gas PG2 containing hydrogen chloride gas is used as the purge gas supply port 111 on the first end 101a side of the reaction vessel 101.
Is supplied in a form along the main back surface 102b side of the susceptor 102 and is discharged to the second end portion 101b side of the reaction container 101.

Vapor phase growth apparatus 10 having such a structure
0 can be, for example, the single-wafer vapor phase growth apparatus 100. Since the single-wafer vapor phase growth apparatus 100 can form a thin film having a flatter surface, the diffusion rate thereof has significantly increased with the recent increase in the diameter of silicon single crystal wafers. In order to manufacture a silicon single crystal wafer having a relatively thin film formed in such an apparatus, it is necessary to supply a large amount of source gas SG into the reaction vessel 101 of the vapor phase growth apparatus 100 for a long time. The adhesion of polysilicon in the reaction vessel 101 becomes particularly remarkable. In that case, the vapor phase growth method of the present invention can be preferably adopted.

In the vapor phase growth method of the present invention, when the load-lock type single wafer type vapor phase growth apparatus 100 is used,
It can be preferably adopted. FIG. 2 schematically shows a configuration example of a load-lock type single-wafer vapor phase growth apparatus 100.
The apparatus comprises a cassette 1 for holding a silicon single crystal substrate W.
A load lock chamber 3 containing 0 therein to carry in and carry out the silicon single crystal substrate W, and a reaction vessel 1 for carrying out a reaction for vapor phase growth of a silicon single crystal thin film on the silicon single crystal substrate W.
01 and a transfer chamber 2 for transferring the silicon single crystal substrate W between the load lock chamber 3 and the reaction container 101.
The reaction container 101 is connected to the transfer chamber 2 via a gate valve 4, and the transfer chamber 2 is connected to the load lock chamber 3 via a gate valve 5.

The load lock chamber 3 can accommodate, for example, one set of cassettes 10 each containing a plurality of silicon single crystal substrates W. The load lock chamber 3 is normally in a nitrogen atmosphere, and nitrogen gas is supplied from the introduction pipe 21 and exhausted from the exhaust pipe 24.

In the transfer chamber 2, a transfer device (not shown) for transferring the silicon single crystal substrate W is placed.
The transfer device extracts silicon single crystal substrates W one by one from the cassette 10 in the load lock chamber 3, transfers the silicon single crystal substrates W into the transfer chamber 2, and transfers the other silicon single crystal substrates W in the reaction vessel 101. It stands by in the transfer chamber 2 until the processing of (3) is completed. Then, after the processing in the reaction container 101 is completed, the gate valve 4 is opened, and the silicon single crystal substrate W is loaded into the reaction container 101. Nitrogen gas is also supplied to the transfer chamber 2 from the introduction pipe 20 and discharged from the exhaust pipe 14, so that the nitrogen atmosphere is maintained.

The load-lock type single-wafer vapor phase growth apparatus 100 as described above is hermetically sealed so that the inside of the reaction vessel 101 is always maintained in a hydrogen atmosphere, and the apparatus is disassembled and each part in the reaction vessel 101 is decomposed. It has a difficult structure to take out. Therefore, it is not easy to individually remove each part (for example, a quartz member) to which polysilicon is attached and perform a cleaning step of removing polysilicon. For example, if the apparatus is disassembled and the inside of the reaction vessel 101 is opened to the atmosphere, a great amount of labor and cost are required to reduce the water taken from the atmosphere into the reaction vessel 101 to the level before decomposition. Becomes As described above, since a great deal of labor is required to remove the polysilicon, it is necessary to prevent the deposition of the polysilicon in the load-lock type single-wafer vapor phase growth apparatus 100.

The vapor phase growth method of the present invention using the vapor phase growth apparatus 100 as described above will be described in detail below with reference to FIGS. 1, 2 and 3. The silicon single crystal substrate W transferred from the load lock chamber 3 into the reaction vessel 101 is
It is placed on main surface 102a of susceptor 102, and vapor phase growth is performed based on the sequence shown in FIG. Figure 3
Is a temperature control sequence for growing a silicon single crystal thin film on the silicon single crystal substrate W and a source gas S.
9 shows a supply sequence of G, a rotary drive system purge gas PG1, and a purge gas PG2 containing hydrogen chloride gas. In the present embodiment, as the source gas SG,
Trichlorosilane (SiHCl ₃ : TCS) gas is used. In FIG. 3, the gas supplied from the raw material gas supply port 107 is collectively represented by SG. Also,
A dopant gas may be supplied as a dopant source to the silicon single crystal thin film together with the source gas SG.

First, the reaction container 1 for the silicon single crystal substrate W.
01, the main surface 102a of the susceptor 102 during loading.
The temperature above is set to 900 ° C and H is supplied from all gas supply ports.
_Two gases are supplied into the reaction vessel 101. Then, when the loading is completed, the main surface 102a of the susceptor 102 is heated to the growth temperature 1110 ° C. by the infrared heating lamp 103 while supplying H ₂ gas into the reaction vessel 101. When the temperature rise to the growth temperature is completed, the silicon single crystal substrate W
The temperature of the susceptor 102 is kept constant until the temperature of the main surface of the is stabilized, and then trichlorosilane (hereinafter, also referred to as TCS) gas is supplied as a source gas SG together with H ₂ gas (at the same time to the silicon single crystal thin film). A dopant gas serving as a dopant source may be supplied). At this time, the rotary drive system purge gas PG1 is only H ₂ gas, but H ₂ gas is used as the purge gas PG2 containing hydrogen chloride gas.
Hydrogen chloride (HCl) gas is supplied together with the _two gases. This prevents the deposition of polysilicon in the region where the purge gas is supplied during vapor phase growth.

When the growth of the silicon single crystal thin film on the silicon single crystal substrate W is completed, the supply of TCS gas and hydrogen chloride gas (and the supply of dopant gas) is stopped, and the temperature of the susceptor 102 is lowered to 900 ° C. The silicon epitaxial wafer on which the silicon single crystal thin film is vapor-phase grown is unloaded from the reaction vessel 101. During this period, the carrier gas and the H ₂ gas as the purge gas are kept supplied. Then, the inside of the reaction container 101 that has been carried out is
After heating to 50 ° C., the raw material gas supply port 1 is provided in the reaction vessel 101.
By supplying hydrogen chloride gas only from 07,
The polysilicon deposited in the reaction vessel 101, especially in the source gas supply region 110 (for example, the main surface 102a of the susceptor 102) can be removed, and the next vapor phase growth is prepared. In this embodiment, the purge gas supply area 12
At 0, since deposition of polysilicon is prevented, it is not necessary to supply HCl gas to the region after vapor phase growth. However, in the present invention, there is no denying that the purge gas PG2 containing hydrogen chloride gas is supplied to the purge gas supply region 120 even after vapor phase growth.

Although the embodiment of the invention has been described above in the case of the single-wafer type vapor phase growth apparatus 100, the present invention is not limited to this, and the vertical type vapor phase growth apparatus (so-called pan) shown below is used. It is also applicable to a cake type vapor phase growth apparatus) and a barrel type (or cylinder type) vapor phase growth apparatus. Figure 7
Shows an example of the vertical vapor deposition apparatus 200.
A susceptor 202 is arranged in a reaction vessel (bell jar) 201, and a plurality of silicon single crystal substrates W are placed on the susceptor 202. An opening 202c is formed at the center of the susceptor 202.
The hollow rotary shaft 205 that is connected to the c
The raw material gas supply nozzle 207 is projected to the main surface 202a side of No. 02. The rotary shaft 205 also serves as the susceptor support 205 that holds the susceptor 202. The source gas supply nozzle 207 supplies the source gas SG to the source gas supply region 210 formed on the main surface 202a side of the susceptor 202. Below the susceptor 202,
An induction heating coil 203 is arranged so as to face the main back surface 202b of the susceptor 202, and the susceptor 202 is heated by the high frequency induction heating of the induction heating coil 203, and vapor phase growth on the silicon single crystal substrate W is performed. Is performed. Further, the induction heating coil 203 has a coil cover 204.
A coil purge gas (not shown) is supplied into the coil cover 204. This prevents the source gas SG from coming into contact with the induction heating coil 203.

In the case of such a vertical vapor deposition apparatus 200, polysilicon is likely to adhere to the main back surface 202b of the susceptor 202. Further, since the susceptor support 205 that supports the susceptor 202 is made of quartz, it is necessary to prevent polysilicon from adhering to the susceptor support 205.
Therefore, the region formed in the gap between the main back surface 202b of the susceptor 202 and the coil cover 204 is the purge gas supply region 220. Then, the susceptor support 205
The connecting portion 208 with the susceptor 202 of the susceptor 202.
The susceptor 20 of the connecting portion 208 is bent toward the outer periphery of the
The end portion of the No. 2 facing the outer peripheral side is the purge gas supply port 211. The susceptor support 205 is a hollow member, and the purge gas PG2 containing hydrogen chloride gas is supplied from the purge gas supply port 211 to the purge gas supply region 220 along the main rear surface 202b of the susceptor 202, and the main rear surface of the susceptor 202. The adhesion of polysilicon to 202b is prevented. A rotary drive system purge gas PG1 containing no hydrogen chloride gas is supplied to a gap region between the peripheral wall portion of the coil cover 204 and the susceptor support 205, and a raw material gas for a rotary drive unit (not shown) connected to the susceptor support 205 is supplied. Prevents contact with SG and other corrosive gases.

FIG. 8 shows an example of the barrel type vapor phase growth apparatus 300. The barrel type vapor phase growth apparatus 300 is provided with a cylindrical reaction vessel (bell jar) 301, and a polygonal frustum-shaped susceptor 302 is arranged at the center of the reaction vessel 301. The susceptor 302
Is a structure in which a plurality of plate-shaped members are circumferentially joined together so that their ends are aligned with each other, and the silicon single crystal substrate W is held on the side slope (main surface of the plate-shaped member) of the susceptor 302. To be done. The susceptor 302 is held in a form of being suspended from above by a susceptor support tool 304 as a quartz member,
It is rotationally driven by a rotary drive unit (not shown) connected to the susceptor support 304. A plurality of infrared heating lamps 306 are arranged on the outer surface side of the reaction vessel 301 so as to face the side slopes of the susceptor 302.
6, the susceptor 302 and the silicon single crystal substrate W are heated. The susceptor support 304 is formed of a hollow member. The susceptor support 304 penetrates the susceptor support 304 and projects into the susceptor 302.
5 are arranged. In addition, the susceptor support 304
Are projected into the susceptor 302, and the opening 31
2 is formed. A source gas supply port 303 is provided above the reaction vessel 301, and the source gas SG supplied from the source container is supplied along the side slope of the susceptor 302, and vapor phase growth on the silicon single crystal substrate W is performed. Is performed. At this time, the side slope of the susceptor 302 (susceptor 30
The region in contact with the second main surface) is the source gas supply region 310.

Barrel type vapor phase growth apparatus 300 as described above
In the above, the source gas SG enters the inner peripheral surface (main back surface) of the polygonal frustum-shaped susceptor 302, and the susceptor support 30
Polysilicon tends to adhere to the inner peripheral portion of No. 4, especially near the opening 312. Polysilicon also adheres to the main back surface of the susceptor 302. Therefore, a region (a hollow inside of the susceptor 302) that is in contact with the main back surface of the susceptor 302 is set as a purge gas supply region 320, and the purge gas PG2 containing hydrogen chloride gas is supplied to the region. In the gap area between the temperature sensor 305 and the susceptor support 304, a tubular member 308 that bisects the gap area is arranged, and an opening 311 formed between the temperature sensor 305 and the tubular member 308 is provided in a rotary drive system. The purge gas supply port 311 is used. On the other hand, the susceptor support 3
04 formed between the cylindrical member 308 and the cylindrical member 308
Is the purge gas supply port 312. From the rotary drive system purge gas supply port 311, a rotary drive system purge gas PG1 for purging a rotary drive unit (not shown) is supplied from the rotary drive unit side to the inside of the susceptor 302 along the tubular member 308 and the temperature sensor 305. To be done. Then, the purge gas PG2 containing the hydrogen chloride gas supplied from the purge gas supply port 312 prevents the deposition of polysilicon on the inner peripheral surface of the susceptor support 304, particularly in the vicinity of the opening 312. Source gas SG and purge gas PG1,
PG2 is discharged from the inside of the reaction container 301 through the discharge port 307.

[0036]

EXAMPLES The present inventor investigated the amount of hydrogen chloride gas contained in the purge gas sufficient to obtain the effect of the present invention when using trichlorosilane (TCS) gas as the source gas as described above. did. The method for investigating the optimum amount of hydrogen chloride gas will be described below. First, the temperature dependence of the deposition rate of silicon during vapor phase growth and the etching rate in the etching process performed after vapor phase growth was investigated. The vapor phase growth apparatus used is shown in FIG.
The single-wafer vapor phase growth apparatus shown in FIG. A H ₂ gas (50 liters / min in the standard state) as a carrier gas diluted with a TCS gas (20 liters / min in the standard state) as a source gas is used. Also, the etching gas is H ₂ gas (50 liters / min in the standard state)
And hydrogen chloride gas (3 liters / min in standard state). FIG. 4 shows the survey result.
As shown in FIG. 4, at a temperature higher than 1000 ° C., the etching rate is higher than the silicon deposition rate. On the other hand, 1
At temperatures lower than 000 ° C, the deposition rate is higher than the etching rate. Thus, when the source gas and the purge gas containing hydrogen chloride gas are supplied to the same region, when the temperature of the region exceeds 1000 ° C., the adhesion of polysilicon tends to be suppressed, and when the temperature is below 1000 ° C. It can be seen that deposition of polysilicon is likely to occur.

Further, from the relationship between the deposition rate and the etching rate in FIG. 4, the growth time is 1150 ° C.
When the growth time was 0 μm and the etching time was 60 seconds, the remaining amount (deposited amount) of polysilicon after performing the vapor phase growth and the etching process at each temperature was estimated. The conditions of the source gas and the etching gas are the same as those in the case of FIG. The results obtained are shown in FIG. In FIG. 5, the remaining amount of- (minus) polysilicon indicates that the polysilicon was etched more than it was deposited.
According to this, even if the temperature is below 1000 ° C.,
At a temperature lower than 00 ° C., although the effect of etching with hydrogen chloride gas is low, the growth rate of silicon is low, so that silicon growth does not occur conspicuously. That is,
It can be seen that during vapor phase growth, deposition of polysilicon does not noticeably occur in the region in the reaction vessel where the temperature is lower than 800 ° C. However, at a temperature of 800 to 1000 ° C. (particularly around 950 ° C.), polysilicon is sufficiently deposited although the effect of etching with hydrogen chloride gas is low. That is, 8 during vapor phase growth
In the region in the reaction vessel where the temperature is from 00 to 1000 ° C. (particularly around 950 ° C.), since polysilicon easily adheres and is difficult to remove, a sufficient amount of polysilicon can be prevented in the region. Hydrogen chloride gas must be included in the purge gas.

Next, in the vapor phase growth apparatus 100 shown in FIG. 1, the TCS gas, the carrier gas (H ₂ gas) and the HCl gas are directed from the source gas supply port 107 toward the silicon single crystal substrate W heated to 950 ° C. Vapor supply was carried out while supplying. Then, by changing the flow rate of the HCl gas, vapor phase growth is performed, and the film thickness of the silicon single crystal thin film grown on the silicon single crystal substrate W is set to H.
It measured with respect to the flow rate of Cl gas. As a result, HCl
The relationship between the partial pressure ratio of the gas and the growth rate of the silicon single crystal was obtained. FIG. 6 shows the result. In FIG. 6, the horizontal axis represents the ratio of partial pressures of HCl gas and TCS gas (P
_HCl / _PTCS ), and the vertical axis represents the growth rate (μm / min) of the silicon single crystal. A- (minus) growth rate indicates that the substrate W was etched.

As can be seen from FIG. 6, P_HCl/ P
_TCSBy setting the value of to 0.6 or more, polysilico
It has been confirmed that the accumulation of hydrogen is effectively prevented. did
Therefore, the TCS gas that enters the purge gas supply region 120
0.6 ≤ P_{H Cl}/ P_TCSThe condition of
Make sure that the purge gas contains only enough hydrogen chloride gas.
To prevent polysilicon from adhering
it can. However, H in the purge gas supply region 120
If the concentration of Cl gas is extremely increased, the source gas supply
As a result of HCl gas penetrating into the area 110, a silicon single crystal
Vapor growth of the thin film becomes unstable. Therefore, P_HCl/
P_TCSIs included in the purge gas so that the value of
It is advisable to control the amount of hydrogen chloride gas charged. Or more
In the vapor phase growth method of the present invention, the source gas SG is
Lichlorosilane (SiHCl_Three) Contains gas
When the purge gas enters the purge gas supply area,
Lichlorosilane (SiHCl_Three) Gas standard partial pressure
To P_TCSHydrogen chloride (HCl) contained in purge gas
The partial pressure of the standard state of gas is P_HClThen, 0.6 ≦ P
_HCl/ P_TCSAmount of hydrogen chloride (HC
l) It should contain gas. In other words, par
Prevents polysilicon from adhering to the digas supply area.
Hydrogen chloride gas in the purge gas
It is preferable to include in.

When vapor phase growth is performed at a growth temperature of 1110 ° C. by the vapor phase growth apparatus shown in FIG. 1, the susceptor 1
The temperature of the region of the No. 02 on the main back surface 102b side is about 950 ° C., which is slightly lower than the growth temperature. Therefore, by supplying the purge gas containing the hydrogen chloride gas satisfying the above conditions to the purge gas supply region 120, it is possible to prevent the adhesion of polysilicon to the quartz susceptor support 104 and the like arranged in the region.

[Brief description of drawings]

FIG. 1 is a schematic view showing a configuration example of a single-wafer vapor phase growth apparatus according to the present invention.

FIG. 2 is a schematic diagram showing a configuration example of a load-lock type single-wafer vapor phase growth apparatus.

FIG. 3 is a diagram showing a gas supply sequence in the vapor phase growth method of the present invention.

FIG. 4 is a diagram showing temperature dependence of deposition rate and etching rate of polysilicon.

FIG. 5 is a diagram showing the remaining amount of polysilicon at each temperature.

FIG. 6 is a diagram showing the relationship between the growth rate of silicon and the flow rate of hydrogen chloride gas.

FIG. 7 is a schematic view showing an example of a vertical vapor phase growth apparatus.

FIG. 8 is a schematic view showing an example of a barrel type vapor phase growth apparatus.

FIG. 9 is a schematic view showing a supply mode of purge gas in a conventional vapor phase growth apparatus.

[Explanation of symbols]

100, 200, 300 vapor phase growth apparatus 101, 201, 301 reaction vessel 102, 202, 302 susceptor 102a susceptor main surface 102b susceptor main back surface 104, 205, 304 susceptor support (quartz member,
(Rotation shaft) 105 Rotational drive unit 110, 210, 310 Raw material gas supply region 120, 220, 320 Purge gas supply region 107 Raw material gas supply port 111, 211, 312 Purge gas supply port 112, 311 Rotational drive system purge gas supply port SG Raw material gas PG1 Rotational drive system Purge gas PG2 Purge gas containing hydrogen chloride gas W Silicon single crystal substrate

Continued front page    F-term (reference) 4K030 AA03 AA06 AA17 BA29 CA04                       CA12 CA17 EA06 EA11 FA10                       GA02 GA08 KA46                 5F045 AA03 AB02 AC03 AC05 AF03                       BB15 DP04 DP16 DP27 EB02                       EE13 EE20 EK12 EM10

Claims (12)

[Claims] 1. A source gas is brought into contact with the main surface of a silicon single crystal substrate placed in a reaction vessel to grow a silicon thin film on the silicon single crystal substrate, while hydrogen chloride gas is fed into the reaction vessel. A vapor deposition method comprising supplying a purge gas containing the gas. 2. A source gas supply region, to which the source gas is mainly supplied in order to bring the source gas into contact with the silicon single crystal substrate during the growth of the silicon thin film, the internal region of the reaction vessel, The purge gas supply area | region where the purge gas is mainly supplied, The purge gas containing the said hydrogen chloride gas is supplied to the said purge gas supply area | region, The vapor phase growth method of Claim 1 characterized by the above-mentioned. 3. The silicon single crystal substrate is held by a susceptor arranged in the reaction vessel, and the purge gas containing hydrogen chloride gas is supplied to a quartz member adjacent to the susceptor. The vapor phase growth method according to claim 2. 4. The purge gas containing hydrogen chloride gas,
4. The vapor phase growth method according to claim 1, further comprising hydrogen chloride gas in an amount capable of preventing deposition of polysilicon. 5. The silicon single crystal substrate is held on the main surface side of the susceptor, the source gas supply region is formed on the main surface side of the susceptor, and the purge gas supply region is on the main back surface side of the susceptor. The vapor phase growth method according to claim 3 or 4, wherein 6. A purge gas containing the hydrogen chloride gas,
The vapor growth method according to claim 3, wherein the susceptor is supplied without being brought into contact with the rotation driving unit. 7. The vapor phase growth method according to claim 1, wherein a silicon single crystal thin film is vapor-phase grown on the silicon single crystal substrate. 8. A reaction container, a raw material gas supply port for supplying a raw material gas onto a silicon single crystal substrate arranged in the reaction container, and a purge gas supply for supplying a purge gas containing hydrogen chloride gas into the reaction container. A vapor phase growth apparatus having a mouth. 9. A source gas supply region, to which the source gas is mainly supplied, is formed on a main surface side of the susceptor holding the silicon single crystal substrate, and a purge gas is mainly supplied to a main back surface side of the susceptor. The vapor phase growth according to claim 8, wherein a purge gas supply region to be supplied is formed, and a purge gas supply port for supplying the purge gas containing the hydrogen chloride gas is connected to the purge gas supply region. apparatus. 10. A purge gas supply port, which has a quartz member adjacent to the susceptor and which supplies the purge gas containing the hydrogen chloride gas, supplies the purge gas containing the hydrogen chloride gas to the quartz member. The vapor phase growth apparatus according to claim 9, wherein 11. A rotary drive unit of the susceptor, and a rotary drive system purge gas supply port for supplying a rotary drive system purge gas for purging the rotary drive unit, wherein the rotary drive system purge gas is hydrogen chloride. The vapor phase growth apparatus according to claim 9 or 10, wherein the apparatus does not contain gas. 12. The purge gas supply port for supplying the purge gas containing the hydrogen chloride gas supplies the purge gas containing the hydrogen chloride gas to the purge gas supply region along the main back surface of the susceptor. The vapor phase growth apparatus according to any one of claims 9 to 11, which is characterized.