阅读说明：本技术 单晶硅的制造方法、整流部件及单晶提拉装置 (method for producing single crystal silicon, rectifying member, and single crystal pulling apparatus ) 是由 小川福生 鸣嶋康人 前川浩一 川上泰史 于 2017-11-14 设计创作，主要内容包括：在本发明的单晶硅的制造方法中,在热屏蔽体(28)的下方配置具备包围单晶硅(SM)的圆环板状主体部(29A)的整流部件,在单晶硅(SM)的培育中,将腔室内部的压力控制为20kPa以上,保持使整流部件与掺杂剂添加熔液(MD)隔开的状态,将不活泼气体(G)导入到单晶硅(SM)与热屏蔽体(28)之间,将不活泼气体(G)分离为第1流通气体(G1)和第2流通气体(G2)。(In the method for manufacturing silicon single crystal, a rectifying member having an annular plate-like body portion (29A) surrounding silicon single crystal (SM) is disposed below a heat shield (28), the pressure inside a chamber is controlled to 20kPa or more during the growth of the silicon single crystal (SM), the rectifying member is kept in a state of being separated from a dopant addition Melt (MD), an inert gas (G) is introduced between the silicon single crystal (SM) and the heat shield (28), and the inert gas (G) is separated into a 1 st flow gas (G1) and a 2 nd flow gas (G2).)

1. A method for manufacturing a silicon single crystal, using a single crystal pulling apparatus, comprising:

A crucible;

A crucible driving part for lifting and rotating the crucible;

A heating unit that heats the crucible to generate a dopant addition melt in which a dopant is added to the silicon melt;

A pulling section for growing single crystal silicon by pulling a seed crystal after contacting the seed crystal with the dopant addition melt;

a cylindrical heat shield provided above the crucible so as to surround the silicon single crystal;

a chamber accommodating the crucible, the heating portion, and the heat shield; and

An introduction part provided at an upper part of the chamber and introducing an inert gas into the chamber,

The method for producing a silicon single crystal is characterized in that,

A rectifying member having an annular plate-like body portion surrounding the silicon single crystal is disposed below the heat shield,

During the growth of the silicon single crystal, the pressure inside the chamber is controlled to be 20kPa or more, and while maintaining a state in which the rectifying member is separated from the dopant addition melt, the inert gas is introduced from above between the silicon single crystal and the heat shield, and is separated into: a 1 st flow gas which is separated from the silicon single crystal along a 1 st flow path between the heat shield and the flow rectification member; and a 2 nd flow gas which is separated from the silicon single crystal along a 2 nd flow path between the rectifying member and the surface of the dopant addition melt.

2. The method of manufacturing single-crystal silicon according to claim 1,

the rectifying member having an inner diameter smaller than an inner diameter of a lower end of the heat shield is disposed to form a gas receiving portion located inside the lower end of the heat shield, and the inert gas is separated into: the 1 st flow gas is guided to the 1 st flow path along the upper surface of the gas receiving portion; and the 2 nd flow gas which passes through the silicon single crystal side of the gas receiving section and is guided to the 2 nd flow path.

3. The method for manufacturing single-crystal silicon according to claim 1 or 2,

growing the single crystal silicon while maintaining the state in which the height of the 1 st channel is higher than the height of the 2 nd channel.

4. The method for manufacturing single-crystal silicon according to any one of claims 1 to 3,

The flow regulating member is provided with an extension portion extending obliquely upward and outward from an outer edge of the main body portion, and the 1 st flow gas is guided to the obliquely upward and outward side.

5. the method of manufacturing single-crystal silicon according to claim 4,

The rectifying member is disposed such that an upper end of the extension portion is positioned above a lower end of the heat shield, and the extension portion suppresses radiant heat from at least 1 of the dopant addition melt, the crucible, and the heating portion from reaching the silicon single crystal via the 1 st flow path.

6. The method for manufacturing single-crystal silicon according to any one of claims 1 to 5,

The rectifying member is provided with a heat insulating material so that radiant heat from at least 1 of the dopant addition melt, the crucible, and the heating unit is prevented from reaching the silicon single crystal by the heat insulating material.

7. A rectifying member attached to a single crystal pulling apparatus, the single crystal pulling apparatus comprising:

A crucible;

a crucible driving part for lifting and rotating the crucible;

A heating unit that heats the crucible to generate a dopant addition melt in which a dopant is added to the silicon melt;

a pulling section for growing single crystal silicon by pulling a seed crystal after contacting the seed crystal with the dopant addition melt;

A cylindrical heat shield provided above the crucible so as to surround the silicon single crystal;

A chamber accommodating the crucible, the heating portion, and the heat shield; and

An introduction part provided at an upper part of the chamber and introducing an inert gas into the chamber,

The rectifying member is characterized by comprising:

A body portion formed in a shape of a circular ring plate surrounding the silicon single crystal below the heat shield, forming a 1 st flow path between the body portion and the heat shield, and forming a 2 nd flow path between the body portion and a surface of the dopant addition melt; and

And an extension portion extending obliquely upward and outward from an outer edge of the main body portion.

8. the fairing component of claim 7,

A heat insulating material is provided inside at least one of the main body portion and the extension portion.

9. a single crystal pulling apparatus is characterized by comprising:

a crucible;

A crucible driving part for lifting and rotating the crucible;

A heating unit that heats the crucible to generate a dopant addition melt in which a dopant is added to the silicon melt;

A pulling section for growing single crystal silicon by pulling a seed crystal after contacting the seed crystal with the dopant addition melt;

a cylindrical heat shield provided above the crucible so as to surround the silicon single crystal;

A chamber accommodating the crucible, the heating portion, and the heat shield;

an introduction part which is provided at an upper part of the chamber and introduces an inert gas into the chamber; and

the fairing component of claim 7 or 8, disposed below the thermal shield.

Technical Field

The present invention relates to a method for manufacturing a silicon single crystal, a rectifying member, and a single crystal pulling apparatus.

Background

Conventionally, a method for manufacturing a silicon single crystal by a CZ method is known (for example, see patent document 1).

The single crystal pulling apparatus of patent document 1 includes: a tubular body coaxially surrounding the single crystal silicon; and a gas flow regulating member provided at a lower end of the tubular body and having a truncated conical surface expanding downward. An opening is provided in the vicinity of a joint between the tubular body and the gas flow regulating member. The inner diameter of the gas rectifying member is set smaller than the inner diameter of the tubular body.

When single crystal silicon is produced using antimony (Sb) as a dopant, most of the downwardly directed inert gas is made to flow from the opening along the frustoconical surface of the gas flow regulating member under a reduced pressure of 100mbar (about 10kPa), and the amount of the inert gas reaching the vicinity of the crystal solidification portion on the melt surface via the inside of the tubular body is reduced, thereby suppressing SiO or Sb₂O₃To increase the oxygen concentration in the crystalline silicon.

Disclosure of Invention

Technical problem to be solved by the invention

In the method of patent document 1, the effect of reducing the evaporation of the dopant is not sufficient.

The invention aims to provide a method for manufacturing monocrystalline silicon, a rectifying member and a monocrystalline pulling device, which can reduce the evaporation of a dopant.

means for solving the technical problem

The method for manufacturing a silicon single crystal according to the present invention uses a single crystal pulling apparatus including: a crucible; a crucible driving part for lifting and rotating the crucible; a heating unit that heats the crucible to generate a dopant addition melt in which a dopant is added to the silicon melt; a pulling section for growing single crystal silicon by pulling a seed crystal after contacting the seed crystal with the dopant addition melt; a cylindrical heat shield provided above the crucible so as to surround the silicon single crystal; a chamber accommodating the crucible, the heating portion, and the heat shield; and an introduction portion that is provided at an upper portion of the chamber and introduces an inert gas into the chamber, wherein a rectifying member including an annular plate-like body portion surrounding the silicon single crystal is disposed below the heat shield, and wherein the inert gas is introduced from above into a space between the silicon single crystal and the heat shield while maintaining a state in which the rectifying member is separated from the dopant addition melt and while controlling a pressure inside the chamber to be 20kPa or higher during the growth of the silicon single crystal, and the inert gas is separated into: a 1 st flow gas which is separated from the silicon single crystal along a 1 st flow path between the heat shield and the flow rectification member; and a 2 nd flow gas which is separated from the silicon single crystal along a 2 nd flow path between the rectifying member and the surface of the dopant addition melt.

According to the present invention, the partial pressure of the dopant volatilized in the chamber is reduced by controlling the pressure in the chamber to be higher than the conventional pressure, that is, to be 20kPa or more, and the evaporation of the dopant from the surface of the dopant addition melt can be reduced. Further, the flow regulating member separates the inert gas into the 1 st flow gas flowing between the heat shield and the flow regulating member and the 2 nd flow gas flowing between the flow regulating member and the surface of the dopant addition melt, whereby the flow rate of the 2 nd flow gas is reduced, and therefore, the evaporation of the dopant from the surface of the dopant addition melt can be reduced.

In the method for manufacturing single-crystal silicon according to the present invention, it is preferable that the rectifying member having an inner diameter smaller than an inner diameter of the lower end of the heat shield is disposed so as to form the gas receiving portion located inside the lower end of the heat shield, and the inert gas is separated into: the 1 st flow gas is guided to the 1 st flow path along the upper surface of the gas receiving portion; and the 2 nd flow gas which passes through the silicon single crystal side of the gas receiving section and is guided to the 2 nd flow path.

According to the present invention, the gas receiving portion is formed at a position inside the lower end of the thermal shield of the main body, so that the flow rate of the 1 st flow gas can be increased. As a result, the flow rate of the 2 nd flow gas is reduced, and therefore, the evaporation of the dopant from the surface of the dopant addition melt can be further reduced.

In the method for producing a silicon single crystal of the present invention, it is preferable that the silicon single crystal is grown while maintaining a state in which the height of the 1 st channel is higher than the height of the 2 nd channel.

According to the present invention, the flow rate of the 1 st flow gas can be increased by keeping the height of the 1 st flow path higher than the height of the 2 nd flow path. As a result, the flow rate of the 2 nd flow gas is reduced, and therefore, the evaporation of the dopant from the surface of the dopant addition melt can be further reduced.

In the method for manufacturing single-crystal silicon according to the present invention, it is preferable that the flow rectification member including an extension portion extending obliquely upward and outward from an outer edge of the main body portion is disposed so as to guide the 1 st flow gas to the obliquely upward and outward side.

According to the present invention, the 1 st flow gas can be kept away from the vicinity of the surface of the dopant addition melt by the extension portion, and the inert gas flowing on the surface of the dopant addition melt can be reduced. As a result, evaporation of the dopant from the surface of the dopant addition melt can be further reduced. Further, since the rectifying member is bent upward from the outer side when viewed as a whole, even if the amount of the dopant addition melt decreases due to the growth of the silicon single crystal, the extension portion on the outer side of the rectifying member does not come into contact with the inner surface of the bottom-shaped crucible having a diameter reduced toward the bottom, such as the round bottom, and the pulling can be continued.

in the method for manufacturing single-crystal silicon according to the present invention, it is preferable that the flow regulating member is disposed such that an upper end of the extension portion is positioned above a lower end of the heat shield, and that the extension portion suppresses radiant heat from at least 1 of the dopant addition melt, the crucible, and the heating portion from reaching the single-crystal silicon through the 1 st flow path.

According to the present invention, the upper end of the extension portion is located above the lower end of the thermal shield, and thus it is possible to suppress radiant heat from at least 1 of the dopant addition melt, the crucible, and the heating portion from reaching the silicon single crystal through the 1 st flow path between the lower end of the thermal shield and the main body portion of the rectifying member. As a result, the temperature gradient in the pulling direction of the silicon single crystal can be increased.

In the method for manufacturing single-crystal silicon according to the present invention, it is preferable that the heat insulator is disposed in the rectifying member having a heat insulator disposed therein, so that radiant heat from at least 1 of the dopant addition melt, the crucible, and the heating unit is prevented from reaching the single-crystal silicon.

According to the present invention, the heat insulating material is provided inside the rectifying member, and thus it is possible to effectively suppress radiant heat from at least 1 of the dopant addition melt, the crucible, and the heating portion from reaching the single crystal silicon.

the rectifying member of the present invention is attached to a single crystal pulling apparatus, and the single crystal pulling apparatus includes: a crucible; a crucible driving part for lifting and rotating the crucible; a heating unit that heats the crucible to generate a dopant addition melt in which a dopant is added to the silicon melt; a pulling section for growing single crystal silicon by pulling a seed crystal after contacting the seed crystal with the dopant addition melt; a cylindrical heat shield provided above the crucible so as to surround the silicon single crystal; a chamber accommodating the crucible, the heating portion, and the heat shield; and an introduction portion that is provided above the chamber and introduces an inert gas into the chamber, the flow regulating member being characterized by comprising: a body portion formed in a shape of a circular ring plate surrounding the silicon single crystal below the heat shield, forming a 1 st flow path between the body portion and the heat shield, and forming a 2 nd flow path between the body portion and a surface of the dopant addition melt; and an extension portion extending obliquely upward and outward from an outer edge of the main body portion.

In the rectifying member according to the present invention, it is preferable that a heat insulator is provided inside at least one of the main body portion and the extension portion.

The single crystal pulling apparatus of the present invention is characterized by comprising: a crucible; a crucible driving part for lifting and rotating the crucible; a heating unit that heats the crucible to generate a dopant addition melt in which a dopant is added to the silicon melt; a pulling section for growing single crystal silicon by pulling a seed crystal after contacting the seed crystal with the dopant addition melt; a cylindrical heat shield provided above the crucible so as to surround the silicon single crystal; a chamber accommodating the crucible, the heating portion, and the heat shield; an introduction part which is provided at an upper part of the chamber and introduces an inert gas into the chamber; and the rectifying member is disposed below the heat shield.

drawings

Fig. 1 is a cross-sectional view of a single crystal pulling apparatus according to an embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view of a rectifying member of the single crystal pulling apparatus.

FIG. 3 is an enlarged cross-sectional view of the vicinity of the rectifying member in the bottom of the crucible when the amount of the dopant addition melt decreases.

Fig. 4 is an explanatory diagram showing the flow of the inert gas in the vicinity of the surface of the dopant addition melt in the case where the flow regulating member does not have the extending portion.

fig. 5 is a graph showing the relationship between the presence or absence of a rectifying member and the chamber internal pressure and the dopant evaporation amount in experiment 1 in the example of the present invention.

Fig. 6 is a graph showing a relationship between the presence or absence of a rectifying member and the resistivity in experiment 2 in the example of the present invention.

FIG. 7 is a graph showing the relationship between the shape of the rectifying member, the dopant evaporation amount, and the temperature gradient ratio in the pulling direction of the silicon single crystal in experiment 3 according to the example of the present invention.

Detailed Description