Silicon carbide epitaxial growth ring and silicon carbide epitaxial growth device

Abstract

The utility model discloses a silicon carbide epitaxial growth ring and a silicon carbide epitaxial growth device. The silicon carbide epitaxial growth ring comprises a ring body, the positioning piece is arranged on the ring body, the inner side edge of the positioning piece is a positioning edge, and the positioning piece can move relative to the ring body in the radial direction of the ring body, so that the position of the positioning edge can be adjusted. Therefore, the size of the positioning edge area can be adjusted, the silicon carbide substrate can be taken and placed more easily, the silicon carbide substrate can be prevented from being broken and scrapped due to operation, a growth gas source can be prevented from entering the back face of the silicon carbide substrate from a gap in the silicon carbide epitaxial growth process, the back face atomization area of a silicon carbide epitaxial wafer can be effectively reduced, and the service life of the silicon carbide epitaxial wafer is prolonged. And the atomization yield is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of semiconductor equipment, in particular to a silicon carbide epitaxial growth ring and a silicon carbide epitaxial growth device. Background Art

[0002] In the prior art, a silicon carbide substrate is placed in the inner ring of a graphite ring, and a conveying device is used to convey the tray and the graphite ring to the reaction chamber, so that the epitaxial growth of the silicon carbide substrate can be carried out. In order to facilitate the pick-up and placement operation of the silicon carbide substrate, a certain position needs to be reserved in the graphite ring. The reserved position is the area of ​​the positioning edge, but because the reserved position of the positioning edge of the inner ring of the graphite ring is relatively large, the silicon carbide substrate cannot completely cover the inner ring, resulting in a gap between the silicon carbide substrate and the positioning edge of the inner ring of the graphite ring. During the growth process, the process gas enters the back of the silicon carbide substrate through the exposed gap, causing the back of the silicon carbide substrate epitaxial wafer to be atomized, affecting the performance and appearance of the silicon carbide substrate epitaxial wafer. Utility Model Content

[0003] The utility model aims to solve at least one of the technical problems existing in the prior art. To this end, the utility model proposes a silicon carbide epitaxial growth ring, the positioning piece of which is movable relative to the ring body along the radial direction of the ring body, so that the size of the positioning edge area can be adjusted, making it easier to take and place the silicon carbide substrate, and can also prevent the silicon carbide substrate from being broken and scrapped due to operation, and can also prevent the growth gas source from entering the back of the silicon carbide substrate through the gap during the silicon carbide epitaxial growth process, and can also effectively reduce the back atomization area of ​​the silicon carbide epitaxial wafer, and improve the atomization yield.

[0004] The utility model further provides a silicon carbide epitaxial growth device.

[0005] According to the first aspect of the present invention, the silicon carbide epitaxial growth ring includes: a ring body; a positioning member, wherein the positioning member is arranged on the ring body, the inner side edge of the positioning member is a positioning edge, and the positioning member is movable relative to the ring body along the radial direction of the ring body to adjust the position of the positioning edge.

[0006] Therefore, the positioning piece of the silicon carbide epitaxial growth ring is movable relative to the ring body along the radial direction of the ring body, and the size of the positioning edge area can be adjusted to make the operation of taking and placing the silicon carbide substrate easier, and can also prevent the silicon carbide substrate from being broken and scrapped due to operation. It can also prevent the growth gas source from entering the back side of the silicon carbide substrate through the gap during the silicon carbide epitaxial growth process, and can also effectively reduce the back side atomization area of ​​the silicon carbide epitaxial wafer and improve the atomization yield.

[0007] According to some embodiments of the present utility model, the ring body is formed with a sliding groove recessed along the thickness direction thereof, and the positioning member is slidably disposed in the sliding groove.

[0008] According to some embodiments of the utility model, the ring body includes: a major arc segment, the outer side of the major arc segment is a major arc shape; an inferior arc segment, the outer side of the inferior arc segment is a inferior arc shape, the inferior arc segment is connected to the major arc segment, and the slide groove is formed in the inferior arc segment.

[0009] According to some embodiments of the utility model, one end of the major arc segment connected to the minor arc segment is provided with one of a guide groove and a guide column, and the positioning member is provided with the other of a guide groove and a guide column, and the guide column and the guide groove are guided and cooperated in the sliding direction of the positioning member.

[0010] According to some embodiments of the utility model, the guide groove includes: a first groove section, the opening of the first groove section is located at the inner side edge of the major arc section; a second groove section, the second groove section is connected to the first groove section and is bent on one side of the thickness direction of the major arc section relative to the first groove section; a third groove section, the third groove section is connected to the second groove section, and the third groove section is parallel to the first groove section.

[0011] According to some embodiments of the present invention, a gap is formed between the positioning member and the inferior arc segment in the thickness direction of the inferior arc segment.

[0012] According to some embodiments of the present invention, the inner side of the inferior arc segment is a straight line, and the width of the inferior arc segment is greater than the width of the superior arc segment.

[0013] According to some embodiments of the present invention, the thickness of the superior arc segment is d1, the thickness of the inferior arc segment is d2, d1 and d2 satisfy the relationship: 2mm≤d2<d1≤10mm, the thickness of the positioning piece is d3, d3 satisfies the relationship: 2mm≤d3≤8mm.

[0014] According to some embodiments of the present invention, the top surface of the ring body is a first inclined surface, and relative to the bottom surface of the ring body, the outer side edge of the top surface of the ring body is lower than the inner side edge of the ring body.

[0015] According to some embodiments of the present invention, the angle between the first inclined surface and the bottom surface of the ring body is α, and α satisfies the relationship: 10°≤α≤20°.

[0016] According to some embodiments of the present invention, the top surface of the positioning member is a second inclined surface, and relative to the bottom surface of the ring body, the inclination angle of the first inclined surface is the same as the inclination angle of the second inclined surface.

[0017] According to some embodiments of the utility model, the positioning member includes: an equal thickness portion, the inner side edge of the equal thickness portion being the positioning edge; and a gradually thinning portion, the gradually thinning portion being connected to the outer side edge of the equal thickness portion, and the thickness of the gradually thinning portion decreasing in a direction away from the equal thickness portion.

[0018] According to some embodiments of the present invention, the ring body is a graphite part with a silicon carbide coating on its outer surface; and / or the positioning part is a graphite part with a silicon carbide coating on its outer surface.

[0019] The silicon carbide epitaxial growth device according to the second aspect of the utility model comprises: a tray, the tray is used to place the silicon carbide substrate; the above-mentioned silicon carbide epitaxial growth ring, the ring body is arranged on the tray.

[0020] Additional aspects and advantages of the present invention will be given in part in the following description, and in part will become apparent from the following description, or will be learned through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0022] Figure 1 is a schematic structural diagram of a silicon carbide epitaxial growth ring according to an embodiment of the utility model;

[0023] Figure 2 is a schematic structural diagram of a ring body according to an embodiment of the utility model;

[0024] Figure 3 is a schematic structural diagram of a positioning member according to an embodiment of the utility model;

[0025] Figure 4 It is a schematic structural diagram of a silicon carbide substrate located in a ring body according to an embodiment of the utility model;

[0026] Figure 5 It is a left side view of the positioning member according to the embodiment of the utility model;

[0027] Figure 6 It is a structural schematic diagram of a ring body provided with a guide groove according to an embodiment of the utility model;

[0028] Figure 7 It is a schematic diagram of the structure of the positioning member and the ring body according to an embodiment of the utility model;

[0029] Figure 8 It is a schematic structural diagram of the positioning member and the thickness of the inferior arc segment according to an embodiment of the utility model;

[0030] Fig. 9It is a structural schematic diagram of a gap formed between a positioning member and a minor arc segment according to an embodiment of the utility model;

[0031] Fig.10 It is a structural schematic diagram of the distribution of fatal defects on the surface of a silicon carbide epitaxial wafer according to Experiment 1 of an embodiment of the utility model;

[0032] Fig.11 It is a structural schematic diagram of the distribution of fatal defects on the surface of a silicon carbide epitaxial wafer according to Experiment 2 of an embodiment of the utility model;

[0033] Fig.12 It is a structural schematic diagram of the distribution of fatal defects on the surface of a silicon carbide epitaxial wafer according to Experiment 3 of an embodiment of the utility model;

[0034] Fig.13 It is a structural schematic diagram of the distribution of fatal defects on the surface of a silicon carbide epitaxial wafer according to Experiment 4 of an embodiment of the utility model;

[0035] Fig.14 It is a structural schematic diagram of the distribution of fatal defects on the surface of a silicon carbide epitaxial wafer according to Experiment 5 of an embodiment of the utility model;

[0036] Fig.15 It is a structural schematic diagram of the distribution of fatal defects on the surface of a silicon carbide epitaxial wafer according to a control experiment of an embodiment of the utility model.

[0037] Reference numerals:

[0038] 100. Silicon carbide epitaxial growth ring;

[0039] 10. Ring body; 11. Slide groove; 12. Superior arc segment; 13. Inferior arc segment;

[0040] 20. Positioning piece; 21. Positioning edge; 22. Equal thickness portion; 23. Gradually thinning portion;

[0041] 30. Guide column;

[0042] 40, guide groove; 41, first groove section; 42, second groove section; 43, third groove section;

[0043] 50. The first inclined plane; 51. The second inclined plane;

[0044] 61. Silicon carbide substrate; 62. Gap. DETAILED DESCRIPTION

[0045] The embodiments of the present utility model are described in detail below. The embodiments described with reference to the accompanying drawings are exemplary. The embodiments of the present utility model are described in detail below.

[0046] Reference below Figure 1-Figure 5A silicon carbide epitaxial growth ring 100 according to an embodiment of the present invention is described.

[0047] Reference Figure 1-Figure 5 As shown, the silicon carbide epitaxial growth ring 100 of the first embodiment of the utility model includes: a ring body 10 and a positioning member 20, the positioning member 20 is arranged on the ring body 10, the inner side edge of the positioning member 20 is a positioning edge 21, and the positioning member 20 is movable relative to the ring body 10 along the radial direction of the ring body 10, so that the position of the positioning edge 21 can be adjusted.

[0048] Specifically, a conventional silicon carbide substrate is placed in the inner ring of a graphite ring, and a conveying device is used to convey the tray and the graphite ring to the reaction chamber, so that the epitaxial growth of the silicon carbide substrate can be performed. In order to facilitate the placement and pick-up of the silicon carbide substrate, a certain position needs to be reserved in the graphite ring. The reserved position is the area of ​​the positioning edge, but because the reserved position of the positioning edge of the inner ring of the graphite ring is relatively large, the silicon carbide substrate cannot completely cover the inner ring, resulting in a gap between the silicon carbide substrate and the positioning edge of the inner ring of the graphite ring. During the growth process, the process gas enters the back of the silicon carbide substrate through the exposed gap, causing the back of the silicon carbide substrate epitaxial wafer to be atomized, affecting the performance and appearance of the silicon carbide substrate epitaxial wafer.

[0049] Therefore, it is necessary to optimize the design of the silicon carbide epitaxial growth ring 100, which is mainly composed of a ring body 10 and a positioning member 20. The inner edge of the positioning member 20 is a positioning edge 21, which can play a positioning role, thereby facilitating accurate placement of the silicon carbide substrate 61.

[0050] Furthermore, the positioning member 20 can move relative to the ring body 10 along the radial direction of the ring body 10, so that the size of the positioning edge 21 area can be adjusted. Before the silicon carbide substrate 61 is placed, the positioning edge 21 area can be adjusted to the maximum, making it easier to take and place the silicon carbide substrate, thereby preventing the silicon carbide substrate from being broken and scrapped due to operation, and preventing the suction pen from touching the side of the graphite ring and introducing particles.

[0051] After the silicon carbide substrate 61 is placed, the positioning member 20 is adjusted along the radial direction of the ring body 10, so that the positioning edge 21 area can be gradually reduced, and a gap between the positioning edge 21 and the silicon carbide substrate 61 can be avoided, thereby preventing the growth gas source from entering the back of the silicon carbide substrate 61 through the gap during the silicon carbide epitaxial growth process, and effectively reducing the back atomization area of ​​the silicon carbide epitaxial wafer and improving the atomization yield. Among them, the back atomization area of ​​the silicon carbide epitaxial wafer is reduced from more than 25% to less than 5%, thereby reducing the production cost.

[0052] Therefore, the positioning piece 20 of the silicon carbide epitaxial growth ring 100 is movable relative to the ring body 10 along the radial direction of the ring body 10, so that the size of the positioning edge 21 area can be adjusted, making it easier to take and place the silicon carbide substrate, and preventing the silicon carbide substrate from being broken and scrapped due to operation. It can also prevent the growth gas source from entering the back side of the silicon carbide substrate 61 through the gap during the silicon carbide epitaxial growth process, and can also effectively reduce the back side atomization area of ​​the silicon carbide epitaxial wafer and improve the atomization yield.

[0053] According to some embodiments of the present invention, the ring body 10 is formed with a slide groove 11 recessed along the thickness direction thereof, and the positioning member 20 is slidably disposed in the slide groove 11 .

[0054] The ring body 10 is provided with a slide groove 11 , which can provide an installation position for the positioning member 20 . The positioning member 20 is arranged in the slide groove 11 to ensure that the upper surface of the positioning member 20 is flush with the upper surface of the ring body 10 .

[0055] Furthermore, the positioning member 20 can slide in the radial direction of the ring body 10 in the slide groove 11. Before the silicon carbide substrate 61 is placed, the positioning member 20 can slide radially outwardly of the ring body 10, so that the positioning edge 21 area can be enlarged, thereby facilitating the placement of the silicon carbide substrate. After the silicon carbide substrate 61 is placed, the positioning member 20 can slide radially inwardly of the ring body 10, so that the positioning area can be gradually reduced, and a gap between the positioning edge 21 and the silicon carbide substrate 61 can be avoided, thereby preventing the growth gas source from entering the back of the silicon carbide substrate 61 through the gap during the silicon carbide epitaxial growth process.

[0056] According to some embodiments of the present utility model, the ring body 10 includes: a major arc segment 12 and a minor arc segment 13, the outer side of the major arc segment 12 is a major arc shape, the outer side of the minor arc segment 13 is a minor arc shape, the minor arc segment 13 is connected to the major arc segment 12, and the slide groove 11 is formed in the minor arc segment 13.

[0057] The ring body 10 is mainly composed of a major arc segment 12 and a minor arc segment 13. The major arc segment 12 can ensure the strength of the ring body 10, and the minor arc segment 13 can facilitate the positioning and placement of the positioning member 20. Furthermore, the minor arc segment 13 is provided with a slide groove 11, and the positioning member 20 can slide radially along the ring body 10 in the slide groove 11, so that the size of the positioning edge 21 area can be adjusted.

[0058] According to a specific embodiment of the utility model, one end where the major arc segment 12 and the minor arc segment 13 are connected is provided with one of the guide groove 40 and the guide column 30, and the positioning member 20 is provided with the other of the guide groove 40 and the guide column 30, and the guide column 30 and the guide groove 40 are guided and matched in the sliding direction of the positioning member 20.

[0059] Specifically, when the positioning member 20 on the inferior arc segment 13 is provided with a guide post 30, the superior arc segment 12 is provided with a guide groove 40 accordingly, and when the positioning member 20 on the inferior arc segment 13 is provided with a guide groove 40, the superior arc segment 12 is provided with a guide post 30 accordingly. The guide post 30 extends into the guide groove 40, which can provide accurate positioning for the movement of the positioning member 20 and can also ensure the correct position of the positioning member 20 during the assembly process.

[0060] Furthermore, the cooperation between the guide post 30 and the guide groove 40 can reduce the friction and wear of the positioning member 20 relative to the major arc segment 12 , and can also extend the service life of the ring body 10 .

[0061] According to some embodiments of the utility model, the guide groove 40 includes: a first groove segment 41, a second groove segment 42 and a third groove segment 43, the opening of the first groove segment 41 is located at the inner side of the major arc segment 12, the second groove segment 42 is connected to the first groove segment 41, and the second groove segment 42 is bent relative to the first groove segment 41 toward one side of the thickness direction of the major arc segment 12, the third groove segment 43 is connected to the second groove segment 42, and the third groove segment 43 is parallel to the first groove segment 41.

[0062] Specifically, when the silicon carbide substrate 61 needs to be unloaded, the positioning member 20 is moved to the third groove section 43 , so that the positioning edge area can be adjusted to maximize the positioning edge area, thereby facilitating the placement and loading of the silicon carbide substrate 61 .

[0063] After the silicon carbide substrate 61 is loaded, the positioning member 20 is locked with the second groove segment 42 to reduce the area of ​​the positioning edge 21 and eliminate a gap between the silicon carbide substrate 61 and the positioning member 20 , thereby preventing process gas from entering the back of the silicon carbide substrate 61 .

[0064] According to some embodiments of the present invention, a gap 62 is formed between the positioning member 20 and the minor arc segment 13 in the thickness direction of the minor arc segment 13 .

[0065] The positioning member 20 and the inferior arc segment 13 form a gap 62 in the thickness direction of the inferior arc segment 13 . For example, the gap 62 can be set to 2 mm. In this way, the position adjustment of the positioning member 20 can be prevented from being blocked due to silicon carbide deposition.

[0066] According to some embodiments of the present invention, the inner side of the minor arc segment 13 is in a straight line shape, and the width of the minor arc segment 13 is greater than the width of the major arc segment 12 .

[0067] The inner side of the inferior arc segment 13 is a straight line, which can make the inner side of the inferior arc segment 13 fit more closely with the silicon carbide substrate 61, thereby avoiding a gap between the inner side of the inferior arc segment 13 and the silicon carbide substrate 61.

[0068] Furthermore, the width of the inferior arc segment 13 is greater than the width of the superior arc segment 12 , so that the sliding area of ​​the positioning member 20 can be increased, thereby increasing the range of adjusting the distance between the positioning member 20 and the silicon carbide substrate 61 .

[0069] According to some embodiments of the present invention, the thickness of the major arc segment 12 is d1, the thickness of the minor arc segment 13 is d2, d1 and d2 satisfy the relationship: 2mm≤d2<d1≤10mm, the thickness of the positioning member 20 is d3, d3 satisfies the relationship: 2mm≤d3≤8mm.

[0070] Among them, the thickness of the major arc segment 12 can be set to be equal thickness. For example, the thickness of the major arc segment 12 can be set to 10 mm, and the minimum thickness of the inferior arc segment 13 can be set to 2 mm. If the thickness is too low, silicon carbide is prone to breakage during epitaxial growth. If the thickness of the inferior arc segment 13 or the major arc segment 12 is too high, the material cost will be higher.

[0071] Moreover, the thickness of the positioning member 20 can be 2 mm to 8 mm, and the thickness of the positioning member 20 can be selected according to the thickness of the major arc segment 12 and the minor arc segment 13. In this way, after the positioning member 20 is installed in the minor arc segment 13, the upper surface of the positioning member 20 is flush with the upper surface of the major arc segment 12, thereby avoiding the formation of a gap between the positioning member 20 and the major arc segment 12.

[0072] According to some embodiments of the present invention, the top surface of the ring body 10 is a first inclined surface 50 , and relative to the bottom surface of the ring body 10 , the outer side of the top surface of the ring body 10 is lower than the inner side of the ring body 10 .

[0073] Among them, the top surface of the ordinary silicon carbide epitaxial growth ring 100 is flat. When the gas source is filled during the growth process, the loose coating particles are easily blown to the surface of the silicon carbide substrate 61, and the falling objects are introduced during the silicon carbide epitaxial process, which is easy to cause fatal defects.

[0074] The first inclined surface 50 has an inclined angle relative to the bottom surface of the ring body 10. When the gas source is filled during the growth process, the loose coating particles tend to fall to the outside of the silicon carbide epitaxial growth ring 100 instead of being blown to the surface of the silicon carbide substrate 61. In this way, the number of dropped objects during the silicon carbide epitaxy process can be reduced, and the particles on the surface of the ring body 10 can be reduced from falling to the surface of the silicon carbide substrate 61 during the silicon carbide epitaxy process, thereby reducing the back side atomization of the silicon carbide epitaxy. At the same time, the generation of fatal defects in silicon carbide epitaxy can also be reduced.

[0075] According to some embodiments of the present invention, the angle between the first inclined surface 50 and the bottom surface of the ring body 10 is α, and α satisfies the relationship: 10°≤α≤20°.

[0076] Among them, the angle between the first bevel 50 and the bottom surface of the ring body 10 can be 10° to 20°. When the angle between the first bevel 50 and the bottom surface of the ring body 10 is 15°, the number of particles of the coating of the ring body 10 falling to the surface of the silicon carbide substrate 61 is greatly reduced, thereby improving the performance and grade of the silicon carbide epitaxial wafer.

[0077] According to some embodiments of the present invention, the top surface of the positioning member 20 is a second inclined surface 51 , and relative to the bottom surface of the ring body 10 , the inclination angle of the first inclined surface 50 is the same as the inclination angle of the second inclined surface 51 .

[0078] Among them, the inclination angle of the first bevel 50 is the same as the inclination angle of the second bevel 51. For example, the angle between the first bevel 50 and the bottom surface of the ring body 10 is 15°. Correspondingly, the angle between the second bevel 51 and the bottom surface of the ring body 10 is also 15°. In this way, the number of particles of the coating of the ring body 10 falling to the surface of the silicon carbide substrate 61 can be further greatly reduced, thereby further improving the performance and grade of the silicon carbide epitaxial wafer.

[0079] According to some embodiments of the utility model, the positioning member 20 includes: an equal-thickness portion 22 and a gradually thinning portion 23, the inner side edge of the equal-thickness portion 22 is a positioning edge 21, the gradually thinning portion 23 is connected to the outer side edge of the equal-thickness portion 22, and the thickness of the gradually thinning portion 23 decreases in the direction away from the equal-thickness portion 22.

[0080] The uniform thickness portion 22 is used to cooperate with the silicon carbide substrate 61 to prevent a gap from being generated between the uniform thickness portion 22 and the silicon carbide substrate 61. The setting of the gradually thinning portion 23 can form an inclined surface on the upper surface of the gradually thinning portion 23, with the inner side of the inclined surface being higher and the outer side being lower.

[0081] When the silicon carbide epitaxial growth ring 100 grows to a certain thickness, the silicon carbide particles on the surface become loose to a certain extent. When the gas source airflow blows over, the particles will fall onto the surface of the silicon carbide substrate 61. The inclined surface formed by the thinning portion 23 can make these particles more inclined to be blown to the outside of the silicon carbide epitaxial growth ring 100, thereby avoiding falling onto the silicon carbide substrate 61.

[0082] According to some embodiments of the present invention, the ring body 10 is a graphite part with a silicon carbide coating on its outer surface, and / or the positioning part 20 is a graphite part with a silicon carbide coating on its outer surface.

[0083] Wherein, graphite parts are arranged on both the ring body 10 and the positioning part 20. The graphite parts have good high-temperature stability and can maintain stable performance in a high-temperature environment. Therefore, the ring body 10 and the positioning part 20 can be used in a high-temperature environment.

[0084] The silicon carbide epitaxial growth device according to the second embodiment of the utility model comprises: a tray and the silicon carbide epitaxial growth ring 100 of the above embodiment, the tray is used to place the silicon carbide substrate 61, and the ring body 10 is arranged on the tray.

[0085] The epitaxial growth process of the silicon carbide epitaxial growth ring 100 carrying the silicon carbide substrate 61 is as follows:

[0086] Step 1: manually loading the silicon carbide substrate 61 into the tray and the silicon carbide epitaxial growth ring 100 in the carrier;

[0087] Step 2: Using a conveying device to convey the carrier device into the reaction chamber;

[0088] Step 3: Control the pressure of the reaction chamber to make the pressure of the reaction chamber 50-250 mbar;

[0089] Step 4: introducing hydrogen gas and maintaining the flow rate at 70 to 140 L / min, using a heating power source to raise the temperature of the reaction chamber to the silicon carbide epitaxial growth temperature, maintaining the temperature for 5 to 15 minutes, and etching the silicon carbide substrate 61;

[0090] Step 5: Buffer layer growth: introducing a certain amount of carbon source, silicon source and doping source to grow a buffer layer with a high doping concentration at a low speed;

[0091] Step 6: Epitaxial layer growth: introducing more carbon source, silicon source and doping source to grow an epitaxial layer with low doping concentration at a high speed.

[0092] Step 7: Cool the epitaxial wafer, turn off the flow of carbon source, silicon source and doping source, maintain the hydrogen flow rate at 70-140 L / min, control the pressure of the reaction chamber at 500-1000 mbr, cool the epitaxial wafer, and transfer the epitaxial wafer to the loading chamber by using a conveying device after the temperature drops to 800-950°C;

[0093] Step 8: After the temperature of the epitaxial wafer drops to room temperature, open the loading chamber and take out the wafer;

[0094] Epitaxial wafer testing: After the epitaxy of silicon carbide substrate 61 is completed, various tests are performed on the epitaxial wafer: defects, flatness, atomization, thickness, roughness, doping concentration, etc. The epitaxial wafer is cleaned and inspected for appearance before shipment.

[0095] The specific experiments are as follows:

[0096] Experiment 1:

[0097] Step 1: Use a tray and a silicon carbide epitaxial growth ring 100 to support a 6-inch SiC substrate;

[0098] Step 2: Use a conveying device to convey the carrier device into the reaction chamber;

[0099] Step 3: Control the pressure of the reaction chamber to make the pressure of the reaction chamber 50-250 mbar;

[0100] Step 4: Introduce hydrogen and maintain a flow rate of 70 to 140 L / min, use a heating power supply to increase the temperature of the reaction chamber to the epitaxial growth temperature, maintain it for 5 to 15 minutes, and etch the SiC substrate.

[0101] Step 5: Buffer layer growth: 20-50 sccm of carbon source, 50-100 sccm of silicon source, and 150-250 sccm of doping source are introduced to grow a buffer layer with high doping concentration at a low speed;

[0102] Step 6: Epitaxial layer growth: A relatively large amount of carbon source (C2H2) 200-300sccm, silicon source (SiHCl3) 90-150sccm and doping source 100-200sccm are introduced to rapidly grow an epitaxial layer with a low doping concentration;

[0103] Step 7: Cooling the epitaxial wafer. Turn off the flow of carbon source, silicon source and doping source, maintain the hydrogen flow rate at 70-140 L / min, control the pressure of the reaction chamber at 500-1000 mbr, cool the epitaxial wafer, and transfer the epitaxial wafer to the loading chamber using a transfer device after the temperature drops to 800-950°C.

[0104] Step 8: After the temperature of the epitaxial wafer drops to room temperature, open the loading chamber to take out the wafer and send the epitaxial wafer for testing.

[0105] Experiment 2:

[0106] Step 1: Use a silicon carbide epitaxial growth ring 100 with an outer surface tilt angle of 5° and a tray to support a 6-inch SiC substrate;

[0107] Step 2: Use a conveying device to convey the carrier device into the reaction chamber;

[0108] Step 3: Control the pressure of the reaction chamber to make the pressure of the reaction chamber 50-250 mbar;

[0109] Step 4: introduce hydrogen and maintain the flow rate at 70-140 L / min, use a heating power supply to raise the temperature of the reaction chamber to the epitaxial growth temperature, maintain for 5-15 minutes, and etch the SiC substrate;

[0110] Step 5: Buffer layer growth: 20-50 sccm of carbon source, 50-100 sccm of silicon source, and 150-250 sccm of doping source are introduced to grow a buffer layer with high doping concentration at a low speed;

[0111] Step 6: Epitaxial layer growth: A relatively large amount of carbon source (C2H2) 200-300sccm, silicon source (SiHCl3) 90-150sccm and doping source 100-200sccm are introduced to rapidly grow an epitaxial layer with a low doping concentration;

[0112] Step 7: Cooling the epitaxial wafer. Turn off the flow of carbon source, silicon source and doping source, maintain the hydrogen flow rate at 70-140L / min, control the pressure of the reaction chamber at 500-1000mbr, cool the epitaxial wafer, and after the temperature drops to 800-950°C, use the conveying device to transfer the epitaxial wafer to the loading chamber;

[0113] Step 8: After the temperature of the epitaxial wafer drops to room temperature, open the loading chamber to take out the wafer and send the epitaxial wafer for testing.

[0114] Experiment 3:

[0115] Step 1: Use a silicon carbide epitaxial growth ring 100 with an outer surface tilt angle of 15° and a tray to support a 6-inch SiC substrate;

[0116] Step 2: Use a conveying device to convey the carrier device into the reaction chamber;

[0117] Step 3: Control the pressure of the reaction chamber to make the pressure of the reaction chamber 50-250 mbar;

[0118] Step 4: introduce hydrogen and maintain the flow rate at 70-140 L / min, use a heating power supply to raise the temperature of the reaction chamber to the epitaxial growth temperature, maintain for 5-15 minutes, and etch the SiC substrate;

[0119] Step 5: Buffer layer growth: 20-50 sccm of carbon source, 50-100 sccm of silicon source, and 150-250 sccm of doping source are introduced to grow a buffer layer with high doping concentration at a low speed;

[0120] Step 6: Epitaxial layer growth: A relatively large amount of carbon source (C2H2) 200-300sccm, silicon source (SiHCl3) 90-150sccm and doping source 100-200sccm are introduced to rapidly grow an epitaxial layer with a low doping concentration;

[0121] Step 7: Cooling the epitaxial wafer. Turn off the flow of carbon source, silicon source and doping source, maintain the hydrogen flow rate at 70-140L / min, control the pressure of the reaction chamber at 500-1000mbr, cool the epitaxial wafer, and after the temperature drops to 800-950°C, use the conveying device to transfer the epitaxial wafer to the loading chamber;

[0122] Step 8: After the temperature of the epitaxial wafer drops to room temperature, open the loading chamber to take out the wafer and send the epitaxial wafer for testing.

[0123] Experiment 4:

[0124] Step 1: Use a silicon carbide epitaxial growth ring 100 with an outer surface tilt angle of 25° and a tray to support a 6-inch SiC substrate;

[0125] Step 2: Use a conveying device to convey the carrier device into the reaction chamber;

[0126] Step 3: Control the pressure of the reaction chamber to make the pressure of the reaction chamber 50-250 mbar;

[0127] Step 4: introduce hydrogen and maintain the flow rate at 70-140 L / min, use a heating power supply to raise the temperature of the reaction chamber to the epitaxial growth temperature, maintain for 5-15 minutes, and etch the SiC substrate;

[0128] Step 5: Buffer layer growth: 20-50 sccm of carbon source, 50-100 sccm of silicon source, and 150-250 sccm of doping source are introduced to grow a buffer layer with high doping concentration at a low speed;

[0129] Step 6: Epitaxial layer growth: A relatively large amount of carbon source (C2H2) 200-300sccm, silicon source (SiHCl3) 90-150sccm and doping source 100-200sccm are introduced to rapidly grow an epitaxial layer with a low doping concentration;

[0130] Step 7: Cooling the epitaxial wafer. Turn off the flow of carbon source, silicon source and doping source, maintain the hydrogen flow rate at 70-140L / min, control the pressure of the reaction chamber at 500-1000mbr, cool the epitaxial wafer, and after the temperature drops to 800-950°C, use the conveying device to transfer the epitaxial wafer to the loading chamber;

[0131] Step 8: After the temperature of the epitaxial wafer drops to room temperature, open the loading chamber to take out the wafer and send the epitaxial wafer for testing.

[0132] Experiment 5:

[0133] Step 1: Use the silicon carbide epitaxial growth ring 100 and the tray to carry the 6-inch SiC substrate, and add an outer surface of the positioning member 20 as a slope with an inclination angle of 15°;

[0134] Step 2: Use a conveying device to convey the carrier device into the reaction chamber;

[0135] Step 3: Control the pressure of the reaction chamber to make the pressure of the reaction chamber 50-250 mbar;

[0136] Step 4: introduce hydrogen and maintain the flow rate at 70-140 L / min, use a heating power supply to raise the temperature of the reaction chamber to the epitaxial growth temperature, maintain for 5-15 minutes, and etch the SiC substrate;

[0137] Step 5: Buffer layer growth: 20-50 sccm of carbon source, 50-100 sccm of silicon source, and 150-250 sccm of doping source are introduced to grow a buffer layer with high doping concentration at a low speed;

[0138] Step 6: Epitaxial layer growth: A relatively large amount of carbon source (C2H2) 200-300sccm, silicon source (SiHCl3) 90-150sccm and doping source 100-200sccm are introduced to rapidly grow an epitaxial layer with a low doping concentration;

[0139] Step 7: Cooling the epitaxial wafer. Turn off the flow of carbon source, silicon source and doping source, maintain the hydrogen flow rate at 70-140L / min, control the pressure of the reaction chamber at 500-1000mbr, cool the epitaxial wafer, and after the temperature drops to 800-950°C, use the conveying device to transfer the epitaxial wafer to the loading chamber;

[0140] Step 8: After the temperature of the epitaxial wafer drops to room temperature, open the loading chamber to take out the wafer and send the epitaxial wafer for testing.

[0141] Control experiment:

[0142] The epitaxial growth is carried out after the SiC substrate is supported by conventional graphite rings and graphite disks.

[0143] Step 1: Use a conventional graphite ring and a graphite growth disk to support the SiC substrate, place the SiC substrate on the supporting disk ring and place it in the loading chamber of the epitaxial furnace.

[0144] Step 2: Use a conveying device to convey the carrier device into the reaction chamber;

[0145] Step 3: Control the pressure of the reaction chamber to make the pressure of the reaction chamber 50-250 mbar;

[0146] Step 4: introduce hydrogen and maintain the flow rate at 70-140 L / min, use a heating power supply to raise the temperature of the reaction chamber to the epitaxial growth temperature, maintain for 5-15 minutes, and etch the SiC substrate;

[0147] Step 5: Buffer layer growth: 20-50 sccm of carbon source, 50-100 sccm of silicon source, and 150-250 sccm of doping source are introduced to grow a buffer layer with high doping concentration at a low speed;

[0148] Step 6: Epitaxial layer growth: A relatively large amount of carbon source (C2H2) 200-300sccm, silicon source (SiHCl3) 90-150sccm and doping source 100-200sccm are introduced to rapidly grow an epitaxial layer with a low doping concentration;

[0149] Step 7: Cooling the epitaxial wafer. Turn off the flow of carbon source, silicon source and doping source, maintain the hydrogen flow rate at 70-140L / min, control the pressure of the reaction chamber at 500-1000mbr, cool the epitaxial wafer, and after the temperature drops to 800-950°C, use the conveying device to transfer the epitaxial wafer to the loading chamber;

[0150] Step 8: After the temperature of the epitaxial wafer drops to room temperature, open the loading chamber to take out the wafer and send the epitaxial wafer for testing.

[0151] Defect Testing

[0152] The defect detector is used to analyze the defects of the epitaxial SiC substrate, and the grade of the epitaxial wafer is determined according to the defect value:

[0153]

[0154] Experimental defect test results

[0155] experiment Number of fatal defects Experiment 1 contains positioning parts 136 Experiment 2: Tilt angle 5° 58 Experiment 3: Tilt angle 15° 20 Experiment 4: Tilt angle 25° 79 Experiment 5 Positioning piece + tilt angle 15° 10 Control experiment 272

[0156] By comparing Experiment 1, Experiment 2, Experiment 3, Experiment 4, Experiment 5 and the control experiment, the following conclusions were drawn:

[0157] A silicon carbide epitaxial growth ring 100 having an outer surface with an inclined surface at an angle of 15° is added to carry the SiC substrate for epitaxial growth. The number of particles of the silicon carbide epitaxial growth ring 100 coating falling onto the surface of the SiC substrate is greatly reduced, thereby improving the performance and grade of the silicon carbide epitaxial wafer.

[0158] In Experiment 2, the number of fatal defects was reduced at an inclination angle of 5°, but the effect was not significant enough. In Experiment 4, the inclination angle of 25° was too large, making the top angular and particles at the corners easy to fall off. Therefore, the fatal defect improvement effect of the inclination angle of 15° was the best.

[0159] Strong light appearance inspection

[0160] The inspector uses a suction pen to absorb the silicon carbide substrate, tilts it at a certain angle, and rotates it clockwise (or counterclockwise) under the illumination of a strong light for visual inspection. In this process, the optical phenomena such as reflection, refraction, and transmission on the silicon carbide substrate are judged, thereby detecting defects on the Si surface (front side) and C surface (back side), such as dirt, residual chemical, scratches, and edge collapse.

[0161] Use strong light to detect the fogging condition on the back of the epitaxial wafer, and divide it into 1 to 3 levels according to the fogging area and color.

[0162] Level 1: Atomization area ≤ 5%

[0163] Level 2: 5%<atomization area<25%

[0164] Level 3: Atomization area > 25%

[0165] The result of strong light visual atomization in experiment 1 was level 1

[0166] The fogging result of strong light visual inspection in Experiment 2 was level 3

[0167] The result of strong light visual atomization in experiment 3 was level 1

[0168] The control experiment's strong light visual atomization result was level 3

[0169] Conclusion: The use of the positioning member 20, and the outer surfaces of the positioning member 20 and the silicon carbide epitaxial growth ring 100 being 15° inclined surfaces, can greatly reduce the back side fogging area of ​​the silicon carbide epitaxial wafer.

[0170] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0171] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the utility model. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example.

[0172] Although the embodiments of the present invention have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A silicon carbide epitaxial growth ring (100), characterized in that: include: Ring body (10); A positioning member (20), wherein the positioning member (20) is arranged on the ring body (10), the inner side edge of the positioning member (20) is a positioning edge (21), and the positioning member (20) is movable relative to the ring body (10) along the radial direction of the ring body (10) to adjust the position of the positioning edge (21).

2. The silicon carbide epitaxial growth ring (100) according to claim 1, characterized in that: The ring body (10) is formed with a sliding groove (11) recessed along the thickness direction thereof, and the positioning member (20) is slidably arranged in the sliding groove (11).

3. The silicon carbide epitaxial growth ring (100) according to claim 2, characterized in that: The ring body (10) comprises: A major arc segment (12), wherein the outer side of the major arc segment (12) is in a major arc shape; An inferior arc segment (13), the outer side of the inferior arc segment (13) is in an inferior arc shape, the inferior arc segment (13) is connected to the superior arc segment (12), and the slide groove (11) is formed in the inferior arc segment (13).

4. The silicon carbide epitaxial growth ring (100) according to claim 3, characterized in that: One end of the major arc segment (12) connected to the minor arc segment (13) is provided with one of a guide groove (40) and a guide column (30), and the positioning member (20) is provided with the other of a guide groove (40) and a guide column (30), and the guide column (30) and the guide groove (40) are guided and matched in the sliding direction of the positioning member (20).

5. The silicon carbide epitaxial growth ring (100) according to claim 4, characterized in that: The guide groove (40) comprises: A first slot segment (41), wherein the opening of the first slot segment (41) is located at the inner side of the major arc segment (12); a second slot segment (42), the second slot segment (42) being connected to the first slot segment (41) and being bent relative to the first slot segment (41) toward one side in the thickness direction of the major arc segment (12); A third slot section (43), the third slot section (43) is connected to the second slot section (42), and the third slot section (43) is parallel to the first slot section (41).

6. The silicon carbide epitaxial growth ring (100) according to claim 4, characterized in that: In the thickness direction of the inferior arc segment (13), a gap (62) is formed between the positioning piece (20) and the inferior arc segment (13).

7. The silicon carbide epitaxial growth ring (100) according to claim 3, characterized in that: The inner side of the inferior arc segment (13) is in a straight line shape, and the width of the inferior arc segment (13) is greater than the width of the superior arc segment (12).

8. The silicon carbide epitaxial growth ring (100) according to claim 3, characterized in that: The thickness of the superior arc segment (12) is d1, the thickness of the inferior arc segment (13) is d2, d1 and d2 satisfy the relationship: 2mm≤d2<d1≤10mm, the thickness of the positioning piece (20) is d3, and d3 satisfies the relationship: 2mm≤d3≤8mm.

9. The silicon carbide epitaxial growth ring (100) according to claim 1, characterized in that: The top surface of the ring body (10) is a first inclined surface (50), and relative to the bottom surface of the ring body (10), the outer side edge of the top surface of the ring body (10) is lower than the inner side edge of the ring body (10).

10. The silicon carbide epitaxial growth ring (100) according to claim 9, characterized in that: The included angle between the first inclined surface (50) and the bottom surface of the ring body (10) is α, and α satisfies the relationship: 10°≤α≤20°.

11. The silicon carbide epitaxial growth ring (100) according to claim 9, characterized in that: The top surface of the positioning member (20) is a second inclined surface (51), and relative to the bottom surface of the ring body (10), the inclination angle of the first inclined surface (50) and the inclination angle of the second inclined surface (51) are the same.

12. The silicon carbide epitaxial growth ring (100) according to claim 1, characterized in that: The positioning member (20) comprises: An equal thickness portion (22), wherein the inner side edge of the equal thickness portion (22) is the positioning edge (21); A gradually thinning portion (23), wherein the gradually thinning portion (23) is connected to the outer side of the equal-thickness portion (22), and the thickness of the gradually thinning portion (23) decreases in a direction away from the equal-thickness portion (22).

13. The silicon carbide epitaxial growth ring (100) according to claim 1, characterized in that: The ring body (10) is a graphite part with a silicon carbide coating on the outer surface; and / or The positioning member (20) is a graphite member with a silicon carbide coating on the outer surface.

14. A silicon carbide epitaxial growth device, characterized in that: include: A tray, the tray being used to place a silicon carbide substrate (61); The silicon carbide epitaxial growth ring (100) according to any one of claims 1 to 13, wherein the ring body (10) is arranged on the tray.

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