CN109666922B

CN109666922B - Graphite base

Info

Publication number: CN109666922B
Application number: CN201811405465.XA
Authority: CN
Inventors: 乔楠; 李昱桦; 刘旺平; 胡加辉; 李鹏
Original assignee: HC Semitek Zhejiang Co Ltd
Current assignee: HC Semitek Zhejiang Co Ltd
Priority date: 2018-11-23
Filing date: 2018-11-23
Publication date: 2021-04-27
Anticipated expiration: 2038-11-23
Also published as: CN109666922A

Abstract

The invention discloses a graphite base, and belongs to the field of epitaxial growth equipment. The substrate placed in the circular groove is mainly in close contact with the side wall part of the second part where the symmetrical plane of the second part is located, so that n arc-shaped grooves are formed in the side wall of the second part, and when n is an even number, an included angle between a symmetrical line of at least one arc-shaped groove in the n arc-shaped grooves and the symmetrical plane of the second part is smaller than 90 degrees; when n is an odd number, the arc surface of one of the arc grooves is intersected with the symmetrical surface of the second part, and the arrangement can ensure that the position where the arc groove is arranged on the part where the substrate is closely contacted with the side wall of the second part. Further, the central angle that the pitch arc corresponds is less than 150, and the substrate can not contact with the arcwall face of arc wall, has reduced the area of contact between the lateral wall of epitaxial layer on substrate, the substrate and the second portion, and then makes holistic temperature comparatively even on substrate and the epitaxial layer, and then improves the luminous degree of consistency of the epitaxial wafer that finally obtains.

Description

Graphite base

Technical Field

The invention relates to the field of epitaxial growth equipment, in particular to a graphite base.

Background

The graphite base is a part of Metal-organic Chemical Vapor Deposition (MOCVD) equipment, the graphite base is a cylinder, a plurality of groups of circular groove units are arranged on the end face of one end of the graphite base, and the circular groove units are distributed along the radial direction of the end face of one end of the graphite base. Each group of circular groove units comprises a plurality of circular grooves, the circular grooves are uniformly distributed along the circumferential direction of the end face of one end of the graphite base, and the other end of the graphite base is connected with a driving structure of the MOCVD equipment.

When the epitaxial wafer is prepared, the substrate needs to be placed in the circular groove, and the graphite base is controlled by the driving structure to rotate by taking the axis of the graphite base as a rotating shaft. The MOCVD equipment controls airflow to form an epitaxial layer on the surface of the substrate, and finally the epitaxial wafer is obtained. However, when the epitaxial wafer is formed on the substrate in this way, the substrate and the epitaxial layer on the substrate are subjected to centrifugal force, and the substrate and one side of the epitaxial layer, which is far away from the center of the graphite susceptor, are in close contact with the side wall of the circular groove. And because the MOCVD equipment transfers heat to the substrate through the contact between the substrate and the circular groove, the temperature of the part of the epitaxial layer, which is in close contact with the side wall of the circular groove, is higher, the temperature of the other part of the epitaxial layer is relatively lower, and the difference of the temperatures of different parts in the epitaxial layer can cause the poor luminous uniformity of the finally produced epitaxial wafer.

Disclosure of Invention

The embodiment of the invention provides a graphite base which can improve the luminous uniformity of a finally obtained epitaxial wafer. The technical scheme is as follows:

the embodiment of the invention provides a graphite base which is a cylinder, a plurality of groups of circular groove units are arranged on the end surface of one end of the graphite base and are distributed along the radial direction of the end surface, each group of circular grooves comprises a plurality of circular grooves which are uniformly distributed along the circumferential direction of the end surface, the centers of circles of the circular grooves are all on the same cylindrical surface,

the cylindrical surface in which the center of the circle of each circular groove is located divides the circular groove into a first part and a second part, the first part is the part of the circular groove close to the center of the circle of the cylindrical surface, the second part is the part of the circular groove far away from the center of the circle of the cylindrical surface,

the side wall of each second part is provided with n arc-shaped grooves, wherein n is more than or equal to 1 and is an integer, each arc-shaped groove comprises an arc-shaped surface, the projection of the arc-shaped surface on the end surface is an arc line, the projection of the circular groove on the end surface is a circle, the central angle corresponding to the arc line is less than 150 degrees,

when n is an even number, the n arc-shaped grooves are respectively arranged at two sides of the symmetrical plane of the second part, and the included angle between the symmetrical line of at least one arc-shaped groove in the n arc-shaped grooves and the symmetrical plane of the second part is less than 90 degrees; when n is an odd number, the arc surface of one of the arc grooves intersects with the symmetrical surface of the second part.

Optionally, when n is an even number, the n arc-shaped grooves are symmetrically arranged on two sides of a symmetric plane of the second portion, when n is an odd number, an arc-shaped plane of one of the arc-shaped grooves intersects with the symmetric plane of the second portion, and in addition, (n-1) arc-shaped grooves are symmetrically arranged on two sides of the symmetric plane of the second portion.

Optionally, the centre of the arc coincides with the centre of the circle.

Optionally, a central angle corresponding to an arc where projections of the n arc-shaped surfaces of the n arc-shaped grooves on the end surface are located is 90 ° to 120 °.

Optionally, the difference between the radius of the arc line and the radius of the circle is 0.5-2 mm.

Optionally, a central angle corresponding to the circular arc is inversely related to the diameter of the cylindrical surface.

Optionally, the central angles of the arcs are 45 ° to 120 °.

Optionally, the radius of the arc line differs from the radius of the circle by 1 mm.

Optionally, the difference between the radius of the arc and the radius of the circle is inversely related to the diameter of the cylindrical surface.

Optionally, n is larger than or equal to 2, and the n arc-shaped grooves are arranged on the circular groove at intervals.

The technical scheme provided by the embodiment of the invention has the following beneficial effects: when the epitaxial wafer is prepared, the substrate placed in the circular groove is mainly in close contact with the side wall part of the second part at the position of the symmetrical plane, so that n arc-shaped grooves are formed in the side wall of the second part, and when n is an even number, the included angle between the symmetrical line of at least one arc-shaped groove in the n arc-shaped grooves and the symmetrical plane of the second part is smaller than 90 degrees; when n is an odd number, the arc surface of one of the arc grooves is intersected with the symmetrical surface of the second part, and the arrangement can ensure that the position where the arc groove is arranged on the part where the substrate is closely contacted with the side wall of the second part. Further, the central angle that the pitch arc corresponds is less than 150, even the substrate can be followed the slight movement of the axis direction of perpendicular circular recess in circular recess under this condition, the position of substrate in circular recess still can be spacing by the lateral wall of second part, the substrate can not be absorbed in the arc wall completely, the substrate can not contact with the arcwall face of arc wall, the substrate has been reduced, area of contact between the epitaxial layer on the substrate and the lateral wall of second part, and then make holistic temperature on substrate and the epitaxial layer comparatively even, and then improve the luminous degree of consistency of the epitaxial wafer that finally obtains.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

FIG. 1 is a schematic structural diagram of a graphite susceptor provided in an embodiment of the present invention;

FIG. 2 is a side view of a graphite susceptor provided in accordance with an embodiment of the present invention;

FIG. 3 is a schematic structural diagram of a circular groove according to an embodiment of the present invention;

fig. 4 is a schematic structural diagram of another circular groove provided in the embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Fig. 1 is a schematic structural diagram of a graphite susceptor according to an embodiment of the present invention, and fig. 2 is a side view of the graphite susceptor according to an embodiment of the present invention, which is a cylinder in combination with fig. 1 and fig. 2. Be provided with the circular recess unit of multiunit 2 on graphite base's the terminal surface 1, the radial equipartition of the terminal surface 1 of graphite base is followed to the circular recess unit of multiunit 2, and every circular recess unit of group 2 all includes a plurality of circular recess 3, and a plurality of circular recess 3 are along graphite base's terminal surface 1's circumference equipartition, and the centre of a circle O of a plurality of circular recess 3 all is on same face of cylinder 4.

The cylindrical surface 4 divides each circular groove 3 into a first portion 31 and a second portion 32, the first portion 31 is a portion of the circular groove 3 close to the center O of the cylindrical surface 4, and the second portion 32 is a portion of the circular groove 3 away from the center O of the cylindrical surface 4.

In this embodiment, the cylindrical surface 4 is a curved surface of a certain cylinder.

Fig. 3 is a schematic structural diagram of a circular groove according to an embodiment of the present invention, and referring to fig. 1 to 3, n arc-shaped grooves 5 are disposed on a side wall of each second portion 32, where n is greater than or equal to 1 and n is an integer, each arc-shaped groove 5 includes an arc-shaped surface, a projection of the arc-shaped surface (not shown in the figure) on the end surface 1 is an arc 51, a projection of the circular groove 3 on the end surface 1 is a circle 33, and a central angle θ corresponding to the arc 51 is less than 150 °.

As shown in fig. 3, the n arc-shaped slots 5 are respectively arranged at two sides of the symmetry plane 321 of the second portion 32, and an included angle γ between the symmetry line 5a of at least one arc-shaped slot 5 of the n arc-shaped slots 5 and the symmetry plane 321 of the second portion 32 is smaller than 90 °; fig. 4 is a schematic structural view of a circular groove provided by an embodiment of the present invention, as shown in fig. 4, a symmetric surface 321 of the second portion 32 intersects with an arc surface of an arc slot 5.

When the epitaxial wafer is prepared, the substrate placed in the circular groove 3 is mainly in close contact with the side wall part at the position of the symmetrical surface 321 of the second part 32, so that n arc-shaped grooves 5 are formed in the side wall of the second part 32, and when n is an even number, the included angle between the symmetrical line of at least one arc-shaped groove 5 in the n arc-shaped grooves 5 and the symmetrical surface 321 of the second part 32 is less than 90 degrees; when n is an odd number, the arc surface of one of the arc-shaped slots 5 intersects the symmetry plane 321 of the second portion 32, and this arrangement ensures that the arc-shaped slot 5 is opened at a position where the substrate is in close contact with the side wall of the second portion 32. Further, the central angle θ corresponding to the arc 51 is smaller than 150 °, even if the substrate can slightly move in the circular groove 3 along the axis direction perpendicular to the circular groove 3 under the condition, the position of the substrate in the circular groove 3 can still be limited by the side wall of the second portion 32, the substrate cannot be completely sunk into the arc groove 5, the substrate cannot be contacted with the arc surface of the arc groove 5, the contact area between the substrate and the side wall of the second portion 32 and the epitaxial layer on the substrate is reduced, the overall temperature on the substrate and the epitaxial layer is uniform, and the luminous uniformity of the finally obtained epitaxial wafer is improved.

As shown in FIG. 3, center O of arc 51 may coincide with center O of circle 33. This arrangement facilitates the fabrication and also significantly reduces the contact area between the substrate and the side walls of the second circular recess 3.

As shown in fig. 3, the arc-shaped slot 5 further includes two side surfaces 52, the two side surfaces 52 of the arc-shaped slot 5 are respectively located at two ends of the arc-shaped surface, and the projections of the two side surfaces 52 on the end surface 1 are respectively located on two diameters of the circular groove 3. This configuration is easier to set up.

In fig. 3, the intersection line of the side surface of the arc-shaped groove 5 and the side wall of the second portion 32 is a straight line, and in other cases provided by the embodiment of the present invention, the junction between the side surface of the arc-shaped groove 5 and the side wall of the second portion 32 may be an arc transition. To further reduce the impact between the substrate and the graphite susceptor.

Referring to fig. 3 and 4, when n is an even number, the n arc-shaped slots 5 may be symmetrically disposed on both sides of the symmetry plane 321 of the second portion 32, as shown in fig. 4, when n is an odd number, the arc-shaped plane of one of the arc-shaped slots 5 intersects with the symmetry plane 321 of the second portion 32, and the n arc-shaped slots 5 are symmetrically disposed on both sides of the symmetry plane 321 of the second portion 32. In both cases, the provision of the arcuate slot 5 where there is a major friction between the substrate and the second portion 32 provides a better reduction in the friction between the substrate and the second portion 32.

In this embodiment, n may be 2 in fig. 3 or 3 in fig. 4, but in other embodiments of the present invention, n may also be 1, 4 or 5.

Furthermore, n is more than or equal to 2, and n arc-shaped grooves 5 are arranged on the circular groove 3 at intervals. With reference to fig. 3, in this arrangement, the edge portion 34 of the circular groove 3 between two adjacent arc-shaped grooves 5 can support the substrate, so as to disperse the acting force between the substrate and the edge of the arc-shaped groove 5 and ensure the service life of the graphite susceptor.

As shown in fig. 3, the shortest distance D between the projections of the arc surfaces of every two adjacent arc-shaped slots 5 on the end surface 1 can be equal. The arrangement is favorable for further dispersing the acting force between the substrate and the graphite base and is favorable for ensuring the service life of the graphite base.

As shown in fig. 3, the central angle θ of the arc 51 may be 45 ° to 120 °. When the central angle θ corresponding to the arc 51 is set in this range, the friction between the substrate and the circular groove 3 can be reduced well.

Illustratively, the central angle α corresponding to the arc 6 on which the n arc-shaped surfaces of the n arc-shaped grooves 5 are projected on the end surface 1 is 90 ° to 120 °. This arrangement can reduce the friction between the substrate and the circular groove 3 to a large extent while ensuring the strength of the graphite base. In fig. 4, the central angle α of the circular arc 6 is 120 °.

Optionally, the central angle α corresponding to the arc 6 on which the n arc surfaces of the n arc grooves 5 project on the end surface 1 is inversely related to the diameter of the cylindrical surface 4. The larger the diameter of the cylindrical surface 4 is, the smaller the contact surface between the substrate and the circular groove 3 in the circular groove 3 on the cylindrical surface 4 is, so that the use strength of the graphite base can be ensured while the friction between the substrate and the circular groove 3 is reduced.

Illustratively, the absolute values of the differences of the central angles α of the corresponding circular arcs 6 on every two adjacent cylindrical surfaces 4 can be equal, the structure is easy to implement, and the effect of reducing the friction between the substrate and the circular groove 3 is also good.

As shown in FIG. 3, the difference d between the radius of the arc 51 and the radius of the circle 33 may be 0.5 to 2 mm. The arrangement can reduce the friction between the substrate and the circular groove 3 and ensure the use strength of the graphite base.

Preferably, the difference d between the radius of arc 51 and the radius of circle 33 may be 1 mm. At this time, the use strength of the graphite susceptor can be further ensured, and the luminous uniformity of the finally obtained epitaxial wafer is not influenced.

Alternatively, the difference d between the radius of arc 51 and the radius of circle 33 is inversely related to the diameter of cylindrical surface 4. The larger the diameter of the cylindrical surface 4 is, the smaller the contact surface between the substrate and the circular groove 3 in the circular groove 3 on the cylindrical surface 4 is, so that the use strength of the graphite base can be ensured while the friction between the substrate and the circular groove 3 is reduced.

Illustratively, the absolute value of the difference d between the radius of the corresponding arc 51 and the radius of the circle 33 on each two adjacent cylindrical surfaces 4 can be equal, which is easy to realize and has a good effect of reducing the friction between the substrate and the circular groove 3.

Further, the absolute value of the difference d between the radius of the corresponding arc 51 and the radius of the circle 33 on each two adjacent cylindrical surfaces 4 may be 0.5 mm. This arrangement also achieves a good effect of reducing the friction between the substrate and the circular groove 3.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.

Claims

1. A graphite base is a cylinder, a plurality of groups of circular groove units are arranged on the end face of one end of the graphite base and are distributed along the radial direction of the end face, each group of circular grooves comprises a plurality of circular grooves which are uniformly distributed along the circumferential direction of the end face, the circle centers of the plurality of circular grooves are all on the same cylindrical surface,

the side wall of each second part is provided with n arc-shaped grooves, wherein n is more than or equal to 1 and is an integer, each arc-shaped groove comprises an arc-shaped surface, the projection of the arc-shaped surface on the end surface is an arc line,

the projection of the circular groove on the end face is circular, the central angle corresponding to the arc line is less than 150 degrees, the central angle corresponding to the arc where the projection of the n arc-shaped surfaces of the n arc-shaped grooves on the end face is 90-120 degrees, the central angle corresponding to the arc is negatively related to the diameter of the cylindrical surface, the difference between the radius of the arc line and the radius of the circular surface is negatively related to the diameter of the cylindrical surface,

2. The graphite susceptor of claim 1, wherein the n arc-shaped slots are symmetrically disposed on both sides of the symmetry plane of the second portion when n is an even number, wherein the arc-shaped plane of one of the arc-shaped slots intersects the symmetry plane of the second portion when n is an odd number, and wherein (n-1) of the arc-shaped slots are symmetrically disposed on both sides of the symmetry plane of the second portion.

3. The graphite susceptor of claim 2, wherein a center of the arc coincides with a center of the circle.

4. The graphite susceptor of claim 3, wherein the difference between the radius of the arc and the radius of the circle is 0.5 to 2 mm.

5. The graphite susceptor of claim 4, wherein the radius of the arc is 1mm different from the radius of the circle.

6. The graphite susceptor of claim 3, wherein the central angles of the arcs are all 45 ° to 120 °.

7. The graphite susceptor of claim 1, wherein n is greater than or equal to 2, and the n arc-shaped grooves are arranged on the circular groove at intervals.