CN111979576A - A kind of container with holes for continuous single crystal silicon growth and design method of holes - Google Patents

Abstract

The invention provides a container with holes for continuous single crystal silicon growth and a method for designing the holes, comprising a container wall arranged in a total melt space, and the space enclosed by the container wall forms a crystal growth area, The crystal growth area is coaxial with the total melt space, and at least one through hole is machined on the wall, and the through hole is used for the melt in the total melt space to enter the crystal growth area , the through hole is located below the melt level in the crystal growth area, and the cross-sectional area of the through hole is 0.1 mm ² ≤ S ≤ 5024 mm ² . The invention realizes the separation of the crystal growth zone by opening through holes on the vessel wall, so that the external unmelted impurity points cannot enter into the crucible, and the through holes realize the replenishment of the melt. The size of the via hole achieves a better improvement in the growth yield of the single crystal.

Description

A kind of container with holes for continuous single crystal silicon growth and design method of holes

technical field

The invention relates to the technical field of continuous Czochralski single crystals, in particular to a container with holes for continuous single crystal silicon growth and a method for designing holes.

Background technique

The obvious feature of the continuous Czochralski single crystal (CCz) process technology is that the crystal is grown while the material is added, which can save the time required for the compounding of ordinary Czochralski single crystals. But at the same time, in the process of compounding, there may be some impurity points that are not fully melted, which may enter the melt and be brought to the crystal growth interface with the melt flow, and cause the crystal structure of the single crystal to be destroyed.

In CCz technology, the melt is generally divided into three areas during crystal growth: the chemical area, the buffer area and the crystal growth area. In order to realize the dislocation-free growth of a single crystal, it is necessary to ensure that the impurity particles can be melted within the time when they enter the crystal growth region from the chemical region.

The prior art clarifies that the time required for the impurity point in the melt from melting to touching the crystal must be long enough that the particle point can be melted in the melt, such as adding some weirs, rings, buffer zones, etc. Such as: patent US2018/012320 and patent US2011002835A1, etc.

However, in the prior art, adding some structures such as weirs, rings, buffer zones, etc., greatly modifies the existing container, and the production cost is relatively high.

SUMMARY OF THE INVENTION

In view of the above-mentioned technical problems, a container with holes for continuous single crystal silicon growth and a method for designing holes are provided.

The technical means adopted in the present invention are as follows:

A vessel with holes for continuous single crystal silicon growth, comprising a vessel wall arranged in a total melt space, the space enclosed by the vessel wall forms a crystal growth area, the crystal growth area and the The total melt space is coaxial;

At least one through hole is machined on the wall;

the through hole is used for the melt in the total melt space to enter the crystal growth zone;

In the present invention, the vessel wall separates the total melt space, the space enclosed by the vessel wall becomes the crystal growth area, and the space outside the vessel wall forms the chemical material area and the buffer zone, and the outside of the vessel wall is arranged so that there is no external The melted impurity points cannot enter the crucible, and the melted melt enters the crystal growth area through the through hole to supplement the raw materials required for the growth of the single crystal.

The movement of particles in the melt mainly includes: the directional movement brought by the melt flow and the Brownian motion of the particles affected by the collision of hot molecules.

Since the melt must pass through the hole to enter the crystal growth area, under the premise of a certain crystal growth rate, it can be known from the law of conservation of mass: V=K/(S*ρ), the directional movement speed brought by the melt flow is inversely proportional to the flow rate. The cross-sectional area of the hole. Assume that the growth rate K=9kg/h, the cross-sectional area of the through hole is S=1cm ² , the silicon melt density ρ=2.5g/cm ³ , and the speed V=1cm/s; if the cross-sectional area of the hole is 0.2cm ² , V =5cm/s The melt flow rate points to the crystal growth area. Therefore, the smaller the hole, the faster the impurity particles move to the crystal, the shorter the time to reach the crystal, and the higher the possibility of crystal structure damage.

And according to the Einstein formula of Brownian motion, the displacement in time t:

where λx _is the average displacement in the X direction, R is the gas constant, N is the molecular density of the melt (atoms/gram), T is the absolute temperature, t is the time, P is the particle radius, and k is the particle moving in the liquid friction coefficient;

The magnitude of the Brownian motion velocity is not affected by the size of the hole. Since the direction of Brownian motion is random, the increase of the hole area will increase the probability of impurity particles free to enter the growing region.

Therefore, the effect of the size of the hole on the crystal growth needs to be comprehensively considered, and it is not as simple as the bigger or the smaller the better. Our experimental research shows that when the crystal growth rate is high, the influence of melt convection on the movement of particle points is more obvious. At this time, it can be considered to increase the opening area; and the concentration of impurity particles in the melt is high (silicon material or In the case of poor quality of the wall), the influence of Brownian motion is more obvious, and the benefit of reducing the opening area is more obvious.

When there is only one through hole, the cross-sectional area of the through hole is 0.1mm ² ≤S≤5024mm ² ;

When there are a plurality of the through holes, the sum of the cross-sectional areas of all the through holes is 0.1 mm ² _{≤Stotal≤5024} mm ² .

Further, the distance h≧10mm between the through hole and the melt level in the crystal growth area.

Our further experiments found that when the purity of the silicon material forming the melt is ≧99.99999%, and the growth rate of the single crystal silicon formed by the melt in the crystal growth zone is K≧5kg/h, if there is only one of the through holes, then The cross-sectional area of the through hole is S≧1mm ² , and if there are multiple through holes, the _sum S of the cross-sectional areas of all the through holes is ≧1mm ² ;

When the purity of the silicon material forming the melt is less than or equal to 99.999%, and the growth rate K of the single crystal silicon formed by the melt in the crystal growth zone is less than or equal to 2kg/h, if there is only one through hole, the cross section of the through hole The area S≤2mm ² . If there are multiple through holes, the _sum S of the cross-sectional areas of all the through holes is less than or equal to 2mm ² .

The through hole is located below the melt level in the crystal growth area; we found that the position of the hole relative to the liquid level also has a significant impact on crystal growth, and the deeper position of the hole below the liquid level will increase the number of impurity particles reaching the crystal. zone time, which is beneficial for crystal growth. The specific position below the liquid level varies according to the amount of melt. Generally, the upper edge of the through hole is required to be at least 1 cm below the liquid level.

The invention also discloses a hole design method for a container with holes for continuous single crystal silicon growth, comprising the following steps:

S1: Obtain the purity data of the silicon material forming the melt;

S2: obtain the growth rate data of the single crystal silicon formed by the melt in the crystal growth area;

S3: According to the silicon material purity data and growth rate data, at least one through hole is opened on the wall for the melt in the total melt space to enter the crystal growth area, and the through hole is located in the crystal growth area. Below the melt level, and when there is only one through hole, the cross-sectional area of the through hole is 0.1mm ² ≤S≤5024mm ² , and when there are multiple through holes, the The sum of the cross-sectional areas is 0.1mm ² _{≤Stotal≤5024mm} ² .

Further, the distance h≧10mm between the upper edge of the through hole and the liquid level of the melt in the crystal growth area.

Further, when the purity of the silicon material forming the melt is greater than or equal to 99.99999%, and the growth rate of the single crystal silicon formed by the melt in the crystal growth zone is K≧ 5kg/h, if there is only one through hole, the through hole is The cross-sectional area S≧1mm ² , if there are multiple through holes, the _sum S of the cross-sectional areas of all the through holes is ≧ 1mm ² ;

When the purity of the silicon material forming the melt is less than or equal to 99.999%, and the growth rate K of the single crystal silicon formed by the melt in the crystal growth zone is less than or equal to 2kg/h, if there is only one through hole, the cross section of the through hole The area S≤2mm ² . If there are multiple through holes, the _sum S of the cross-sectional areas of all the through holes is less than or equal to 2mm ² .

The vessel wall mentioned in the present invention can be a device such as a quartz crucible, and the inside of the crucible is a crystal growth zone.

Compared with the prior art, the present invention has the following advantages:

1. The present invention realizes the separation of the crystal growth area by opening through holes on the vessel wall, so that the unmelted impurity points on the outside cannot enter the crucible.

2. The present invention realizes the replenishment of the melt by arranging through holes on the wall of the vessel.

3. The present invention achieves better improvement of the growth yield of the single crystal by setting the size of the through hole.

Based on the above reasons, the present invention can be widely promoted in the technical field of continuous Czochralski single crystals.

Description of drawings

In order to illustrate the embodiments of the present invention or the technical solutions in the prior art more clearly, the following briefly introduces the accompanying drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description These are some embodiments of the present invention, and for those of ordinary skill in the art, other drawings can also be obtained from these drawings without any creative effort.

FIG. 1 is a schematic structural diagram of a container with holes for continuous single crystal silicon growth in a specific embodiment of the present invention.

FIG. 2 is a diagram showing the arrangement of through holes on the device wall in the specific embodiment of the present invention.

Detailed ways

It should be noted that the embodiments of the present invention and the features of the embodiments may be combined with each other under the condition of no conflict. The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with the embodiments.

In order to make the purposes, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments It is only a part of the embodiments of the present invention, but not all of the embodiments. The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

It should be noted that the terminology used herein is for the purpose of describing specific embodiments only, and is not intended to limit the exemplary embodiments according to the present invention. As used herein, unless the context clearly dictates otherwise, the singular is intended to include the plural as well, furthermore, it is to be understood that when the terms "comprising" and/or "including" are used in this specification, it indicates that There are features, steps, operations, devices, components and/or combinations thereof.

The relative arrangement of the components and steps, the numerical expressions and numerical values set forth in these embodiments do not limit the scope of the invention unless specifically stated otherwise. Meanwhile, it should be understood that, for convenience of description, the dimensions of various parts shown in the accompanying drawings are not drawn in an actual proportional relationship. Techniques, methods, and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the authorized specification. In all examples shown and discussed herein, any specific values should be construed as illustrative only and not limiting. Accordingly, other examples of exemplary embodiments may have different values. It should be noted that like numerals and letters refer to like items in the following figures, so once an item is defined in one figure, it does not require further discussion in subsequent figures.

In the description of the present invention, it should be understood that the orientations indicated by orientation words such as "front, rear, top, bottom, left, right", "horizontal, vertical, vertical, horizontal" and "top, bottom" etc. Or the positional relationship is usually based on the orientation or positional relationship shown in the drawings, which is only for the convenience of describing the present invention and simplifying the description, and these orientation words do not indicate or imply the indicated device or element unless otherwise stated. It must have a specific orientation or be constructed and operated in a specific orientation, so it should not be construed as a limitation on the scope of protection of the present invention: the orientation words "inside and outside" refer to the inside and outside relative to the contour of each component itself.

For ease of description, spatially relative terms, such as "on", "over", "on the surface", "above", etc., may be used herein to describe what is shown in the figures. The spatial positional relationship of one device or feature shown to other devices or features. It should be understood that spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as "above" or "over" other devices or features would then be oriented "below" or "over" the other devices or features under its device or structure". Thus, the exemplary term "above" can encompass both an orientation of "above" and "below." The device may also be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptions used herein interpreted accordingly.

In addition, it should be noted that the use of words such as "first" and "second" to define components is only for the convenience of distinguishing corresponding components. Unless otherwise stated, the above words have no special meaning and therefore cannot be understood to limit the scope of protection of the present invention.

As shown in Figures 1-2, a vessel with holes for continuous single crystal silicon growth includes a vessel wall 2 arranged in a total melt space 1, and the space enclosed by the vessel wall 2 forms a crystal Growth zone 3, the crystal growth zone 3 is coaxial with the total melt space 1;

At least one through hole 4 is processed on the wall 2;

The through hole 4 is used for the melt in the total melt space 1 to enter the crystal growth zone 3;

The through hole 4 is located below the melt level 5 in the crystal growth zone 3;

The melt in the crystal growth zone 3 grows into a single crystal, and the single crystal is pulled out from the melt by a pulling system 6 (such as a cable), and the pulling speed is the growth speed.

The distance h≧10mm between the upper edge of the through hole and the liquid level of the melt in the crystal growth zone.

When the purity of the silicon material forming the melt is ≧ 99.99999%, and the growth rate of the single crystal silicon formed by the melt in the crystal growth zone is K≧ 5kg/h, if there is only one through hole, the cross section of the through hole The area S≧1mm ² , if there are multiple through holes, the _sum S of the cross-sectional areas of all the through holes is ≧ 1mm ² ;

When the purity of the silicon material forming the melt is less than or equal to 99.999%, and the growth rate K of the single crystal silicon formed by the melt in the crystal growth zone is less than or equal to 2kg/h, if there is only one through hole, the cross section of the through hole The area S≤2mm ² . If there are multiple through holes, the _sum S of the cross-sectional areas of all the through holes is less than or equal to 2mm ² .

The arrangement position and size of the through holes are described in detail with reference to the following embodiments. In this embodiment, circular holes are used for the convenience of explanation, but are not limited to round holes, and only need to ensure their positions and cross-sectional areas. One through hole is used in all the following embodiments.

In this embodiment, the container is a crucible, the wall of the crucible is the wall, and the crucible is made of high-purity quartz sand with a purity of 99.995%, and an arc-method fused silica crucible.

The way of opening the through hole can be mechanical drilling with a diamond drill, laser drilling or electrochemical drilling.

The diameter of the crucible is 20 inches to 30 inches, the height is 10 cm to 60 cm, and the wall thickness of the crucible is 5 mm to 30 mm.

Example 1

When the purity of the silicon material is ≧99.9999999% and the growth rate K=8kg/h, the cross-sectional area of the through hole 4 is 20mm ² (5mm in diameter), and the upper edge of the through hole 4 is located in the At 50mm below the melt level in the crucible, the crystal growth yield was 93%.

Example 2

When the purity of the silicon material is ≧99.9999999%, and the growth rate K=8kg/h, the cross-sectional area of the through hole 4 is 5024mm ² (diameter is 80mm) (see Figure 2, the through hole in the other embodiments 4), the upper edge of the through hole 4 is located 50 mm below the melt level in the crucible, and the crystal growth yield is 15%.

Example 3

When the purity of the silicon material is ≧99.9999996% and the growth rate K=9kg/h, the cross-sectional area of the through hole 4 is 0.1mm ² (0.35mm in diameter), and the upper edge of the through hole 4 is located at At 50 mm below the melt level in the crucible, the crystal growth yield is 28%.

Example 4

When the purity of the silicon material is ≧99.99999998% and the growth rate K=10kg/h, the cross-sectional area of the through hole 4 is 113mm ² (diameter is 12mm), and the upper edge of the through hole 4 is located in the At 40 mm below the melt level in the crucible, the crystal growth yield was 92%.

Example 5

When the purity of the silicon material is ≧99.99999999% and the growth rate K=9kg/h, the cross-sectional area of the through hole 4 is 38mm ² (7mm in diameter), and the upper edge of the through hole 4 is located in the At 70mm below the melt level in the crucible, the crystal growth yield is 95%.

Example 6

When the purity of the silicon material is ≧99.99999999% and the growth rate K=14kg/h, the cross-sectional area of the through hole 4 is 154mm ² (diameter is 14mm), and the upper edge of the through hole 4 is located in the At 30mm below the melt level in the crucible, the crystal growth yield was 94%.

Example 7

When the purity of the silicon material is ≧99.99999%, and the growth rate K=4kg/h, the cross-sectional area of the through hole 4 is 7mm ² (3mm in diameter), and the upper edge of the through hole 4 is located in the At 50mm below the melt level in the crucible, the crystal growth yield is 88%.

Example 8

When the purity of the silicon material is ≧99.99999% and the growth rate K=5kg/h, the cross-sectional area of the through hole 4 is 3mm ² (diameter is 2mm), and the upper edge of the through hole 4 is located in the At 80mm below the melt level in the crucible, the crystal growth yield was 92%.

Example 9

When the purity of the silicon material is ≧99.999999% and the growth rate K=10kg/h, the cross-sectional area of the through hole 4 is 113mm ² (diameter is 12mm), and the upper edge of the through hole 4 is located in the At 20 mm below the melt level in the crucible 5, the crystal growth yield reached 92%.

Example 10

When the purity of the silicon material is ≤99.99% and the growth rate K=1.7kg/h, the cross-sectional area of the through hole 4 is 1 mm ² (0.6 mm in diameter), and the upper edge of the through hole 4 is located at At a position 20 mm below the melt level 5 in the crucible, the crystal growth yield is 88%.

Example 11

When the purity of the silicon material is ≤99.998% and the growth rate K=1.5kg/h, the cross-sectional area of the through hole 4 is 1.5mm ² (diameter is 0.7mm), and the upper edge of the through hole 4 At a position 20 mm below the melt level 5 in the crucible, the crystal growth yield reached 91%.

Example 12

When the purity of the silicon material is ≤99.9% and the growth rate K=1kg/h, the cross-sectional area of the through hole 4 is 0.5mm ² (0.45mm in diameter), and the upper edge of the through hole 4 is located at At a position 20 mm below the melt level 5 in the crucible, the crystal growth yield reached 89%.

Example 13

When the purity of the silicon material is less than or equal to 99.999% and the growth rate K=2kg/h, the cross-sectional area of the through hole 4 is 2 mm ² (diameter is 1.6 mm), and the upper edge of the through hole 4 is located at the The crystal growth yield was 29% at 20 mm below the melt level 5 in the crucible.

Example 14

When the purity of the silicon material is less than or equal to 99.99%, the growth rate K=1kg/h, the cross-sectional area of the through hole 4 is 2 mm ² (diameter is 1.6 mm), and the upper edge of the through hole 4 is located at the The crystal growth yield was 24% at a position 20 mm below the melt level 5 in the crucible.

Example 15

The invention also discloses a hole design method for a container with holes for continuous single crystal silicon growth, comprising the following steps:

S1: Obtain the purity data of the silicon material forming the melt;

S2: obtain the growth rate data of the single crystal silicon formed by the melt in the crystal growth area;

S3: According to the silicon material purity data and growth rate data, at least one through hole 4 is opened on the wall 2 for the melt in the total melt space 1 to enter the crystal growth area 3, and the through hole 4 is located in the Below the melt level 5 in the crystal growth zone 3, and when there is only one through hole 4, the cross-sectional area of the through hole 4 is 0.1 mm ² ≤ S ≤ 5024 mm ² , and when there are a plurality of the through holes 4 When the hole 4 is used, the sum of the cross-sectional areas of all the through holes 4 is 0.1 mm ² ≤ S _total ≤ 5024 mm ² .

The distance h≧10mm between the upper edge of the through hole 4 and the melt level 5 in the crystal growth zone 3 .

When the purity of the silicon material forming the melt is ≧ 99.99999%, and the growth rate of the single crystal silicon formed by the melt in the crystal growth zone 3 is K≧ 5kg/h, if there is only one through hole 4, the through hole 4 The cross-sectional area S≧4mm ² , if there are a plurality of the through holes 4, the _sum S of the cross-sectional areas of all the through holes 4 is ≧ 4mm ² ;

When the purity of the silicon material forming the melt is less than or equal to 99.999%, and the growth rate K of the single crystal silicon formed by the melt in the crystal growth zone 3 is less than or equal to 2 kg/h, if there is only one through hole 4, the through hole 4 The cross-sectional area S≤2mm ² , if there are multiple through holes 4 , the _sum S of the cross-sectional areas of all the through holes 4 is less than or equal to 2mm ² .

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, but not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: The technical solutions described in the foregoing embodiments can still be modified, or some or all of the technical features thereof can be equivalently replaced; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the technical solutions of the embodiments of the present invention. scope.

Claims (6)

1. A container with holes for the growth of continuous single crystal silicon, comprising a wall arranged in the total melt space, the space enclosed by the wall forms a crystal growth zone, and the crystal growth zone is The total melt space is coaxial, and is characterized in that: At least one through hole is machined on the wall; the through hole is used for the melt in the total melt space to enter the crystal growth zone; the through hole is located below the melt level in the crystal growth zone; When there is only one through hole, the cross-sectional area of the through hole is 0.1mm ² ≤S≤5024mm ² ; When there are a plurality of the through holes, the sum of the cross-sectional areas of all the through holes is 0.1 mm ² _{≤Stotal≤5024} mm ² . 2. A kind of container with holes for continuous monocrystalline silicon growth according to claim 1, is characterized in that: The distance h≧10mm between the upper edge of the through hole and the liquid level of the melt in the crystal growth zone. 3. A kind of container with hole for continuous monocrystalline silicon growth according to claim 1 or 2, it is characterized in that: When the purity of the silicon material forming the melt is ≧ 99.99999%, and the growth rate of the single crystal silicon formed by the melt in the crystal growth zone is K≧ 5kg/h, if there is only one through hole, the cross section of the through hole The area S≧1mm ² , if there are multiple through holes, the _sum S of the cross-sectional areas of all the through holes is ≧ 1mm ² ; When the purity of the silicon material forming the melt is less than or equal to 99.999%, and the growth rate K of the single crystal silicon formed by the melt in the crystal growth zone is less than or equal to 2kg/h, if there is only one through hole, the cross section of the through hole The area S≤2mm ² . If there are multiple through holes, the _sum S of the cross-sectional areas of all the through holes is less than or equal to 2mm ² . 4. A method for designing a hole for a container with a hole for continuous monocrystalline silicon growth, comprising the steps of: S1: Obtain the purity data of the silicon material forming the melt; S2: obtain the growth rate data of the single crystal silicon formed by the melt in the crystal growth area; S3: According to the silicon material purity data and growth rate data, at least one through hole is opened on the wall for the melt in the total melt space to enter the crystal growth area, and the through hole is located in the crystal growth area. Below the melt level, and when there is only one through hole, the cross-sectional area of the through hole is 0.1mm ² ≤S≤5024mm ² , and when there are multiple through holes, the The sum of the cross-sectional areas is 0.1mm ² _{≤Stotal≤5024mm} ² . 5. A method for designing a hole of a container with a hole for continuous single crystal silicon growth according to claim 4, characterized in that; The distance h≧10mm between the upper edge of the through hole and the liquid level of the melt in the crystal growth zone. 6. The method for designing a hole of a container with a hole for continuous single crystal silicon growth according to claim 4 or 5, characterized in that; When the purity of the silicon material forming the melt is ≧ 99.99999%, and the growth rate of the single crystal silicon formed by the melt in the crystal growth zone is K≧ 5kg/h, if there is only one through hole, the cross section of the through hole The area S≧1mm ² , if there are multiple through holes, the _sum S of the cross-sectional areas of all the through holes is ≧ 1mm ² ; When the purity of the silicon material forming the melt is less than or equal to 99.999%, and the growth rate K of the single crystal silicon formed by the melt in the crystal growth zone is less than or equal to 2kg/h, if there is only one through hole, the cross section of the through hole The area S≤2mm ² . If there are multiple through holes, the _sum S of the cross-sectional areas of all the through holes is less than or equal to 2mm ² .

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