Crucible structure for growing gallium oxide single crystal by VB method

Abstract

The utility model relates to the technical field of gallium oxide crystal growth, and discloses a crucible structure for growing a gallium oxide single crystal by a VB method, which comprises a crucible shell, a seed crystal cavity, a diameter-expanding cavity, a diameter-reducing cavity, a shoulder-expanding cavity and an equal-diameter cavity, the seed crystal cavity, the diameter-expanding cavity, the diameter-reducing cavity, the shoulder-expanding cavity and the equal-diameter cavity are arranged in the crucible shell, the seed crystal cavity is arranged at one end of the crucible shell, and the diameter-reducing cavity is arranged at the other end of the crucible shell. One end of the seed crystal cavity is closed, the other end of the seed crystal cavity is connected with the diameter-expanding cavity, the diameter-expanding cavity is connected with the diameter-reducing cavity, the diameter-reducing cavity is connected with the shoulder-expanding cavity, the shoulder-expanding cavity is connected with the equal-diameter cavity, and the other end of the equal-diameter cavity is open. Through reasonable design of a gallium oxide growth technology, the crucible shell, the seed crystal cavity, the diameter-expanding cavity, the diameter-reducing cavity, the shoulder-expanding cavity and the equal-diameter cavity are adopted, so that gallium oxide crystals can be separated from the crucible wall during growth and cooling, dislocation proliferation and twin crystal structures are not easy to appear, the crystal dislocation density is reduced, and the performance of a semiconductor chip is improved. The crucible structure can be used for preparing cylindrical gallium oxide single crystals with low dislocation density.

Description

Technical Field

[0001] This utility model relates to the field of gallium oxide crystal growth technology, specifically to a crucible structure for growing gallium oxide single crystals using the VB method. Background Technology

[0002] Ga2O3 single crystals are considered the most promising fourth-generation semiconductor material. Five crystal morphologies have been identified so far: α, β, γ, δ, and ε. Among them, the β structure is the most stable and easy to prepare, making it an excellent wide-bandgap semiconductor material. Gallium oxide, compared to silicon carbide and gallium nitride, has a wider bandgap (approximately 4.9 eV) and a theoretical critical breakdown field of 8 MV / cm. It is an emerging ultra-wide bandgap semiconductor material that can be used to fabricate power devices, microwave radio frequency devices, and solar-blind ultraviolet detectors, among other semiconductor devices. It has significant application value in high-voltage power control, radio frequency communication, and flame detection.

[0003] β-Ga2O3 is suitable for melt growth, with fast growth speed and lower growth cost, making it a new generation of semiconductor material supporting the rapid development of information, energy, transportation, manufacturing, and defense. Currently, the main methods for preparing β-Ga2O3 single crystals include Czochralski (CZ), Vertical Bridgman (VB), and EEG (EFG). The EEG method currently used in the market mainly grows sheet-like β-gallium oxide single crystals. Because β-gallium oxide single crystals belong to the monoclinic crystal system, their crystal structure characteristics determine that the main surface of the single crystal sheet prepared by the EEG method is usually the (100) plane. The epitaxial growth rate of gallium oxide is related to the crystal orientation of the substrate; homoepitaxial growth of the (100) plane is the most difficult, while the (001) and (010) planes are easier. In the preparation of gallium oxide semiconductor wafer substrates, the (010) and (001) planes are preferred as the main surface of the substrate. This results in the EEG method being unable to meet the requirements for large-size substrate preparation, necessitating the preparation of thick crystals with oblique side cutting, which is difficult to achieve using the EEG method for growing thick crystals. Although the Czochralski method can be used to prepare single-crystal material substrates with (010) and (001) main surfaces, it is impossible to obtain uniformly doped gallium oxide single crystals due to the segregation coefficient of the doping elements.

[0004] The VB method and its modified form are currently considered ideal growth methods for obtaining (010) and (001) crystal planes as the main surfaces. However, because the crystal is constantly in contact with the crucible wall during growth and cooling, the VB method is prone to dislocation multiplication and twinning, resulting in a high dislocation density and affecting semiconductor chip performance. Commercially available crucibles typically use a combination of a large cavity with a small cavity at the bottom to hold and grow gallium oxide crystals, which also leads to dislocation multiplication and twinning, resulting in a high dislocation density and affecting semiconductor chip performance.

[0005] Therefore, existing gallium oxide growth technologies need further improvement to address the above issues. Utility Model Content

[0006] The purpose of this invention is to overcome the problems of existing gallium oxide growth methods, such as the crystal always being in contact with the crucible wall during growth and cooling, which easily leads to dislocation multiplication and twinning, resulting in high dislocation density and affecting semiconductor chip performance. By rationally designing gallium oxide growth technology and using a crucible shell, seed crystal cavity, diameter expansion cavity, diameter reduction cavity, shoulder expansion cavity, and equal diameter cavity, the gallium oxide crystal can be separated from the crucible wall during growth and cooling, making it less prone to dislocation multiplication and twinning, reducing crystal dislocation density, and improving semiconductor chip performance.

[0007] The specific technical solution of this utility model is as follows:

[0008] A crucible structure for growing gallium oxide single crystals using the VB method, the crucible structure comprising: a crucible shell, a seed crystal cavity, an expansion cavity, a reduction cavity, a shoulder cavity, and a constant-diameter cavity. The seed crystal cavity, expansion cavity, reduction cavity, shoulder cavity, and constant-diameter cavity are disposed within the crucible shell. The seed crystal cavity is located at one end of the crucible shell and is closed at one end. The other end of the seed crystal cavity is connected to the expansion cavity, the expansion cavity is connected to the reduction cavity, the reduction cavity is connected to the shoulder cavity, and the shoulder cavity is connected to the constant-diameter cavity. The other end of the constant-diameter cavity is open.

[0009] Furthermore, the expanded shoulder cavity is selected as a frustum-shaped expanded shoulder cavity or a truncated cone-shaped expanded shoulder cavity, the large-size end of the expanded shoulder cavity is connected to the equal-diameter cavity, and the small-size end of the expanded shoulder cavity is connected to the reduced-diameter cavity.

[0010] Furthermore, the expansion cavity is selected as a prism-shaped expansion cavity or a cylindrical expansion cavity.

[0011] Furthermore, the size of the expanding cavity is larger than the size of the contracting cavity.

[0012] Furthermore, the seed crystal cavity is selected as a prism-shaped seed crystal cavity or a cylindrical seed crystal cavity.

[0013] Furthermore, the size of the seed crystal cavity is smaller than the size of the diameter expansion cavity.

[0014] Furthermore, the outer shell of the crucible is made of iridium, iridium alloy, or platinum-rhodium alloy.

[0015] Furthermore, the thickness of the crucible shell is selected to be 0.1mm to 2mm.

[0016] Furthermore, at least one expansion cavity and at least one reduction cavity are selected, and the number of expansion cavities is equal to the number of reduction cavities. Each expansion cavity and each reduction cavity connected to it are set as a group, and the reduction cavities in each group are interconnected with the expansion cavities in the adjacent group.

[0017] Furthermore, the included angle α of the shoulder expansion cavity is selected to be 60° to 150°.

[0018] Furthermore, the seed crystal cavity, the diameter expansion cavity, the diameter reduction cavity, and the constant diameter cavity are all selected as regular square prisms or cylinders.

[0019] Furthermore, the seed crystal cavity, the diameter-expanding cavity, the diameter-reducing cavity, and the constant-diameter cavity are all preferably cylindrical.

[0020] Furthermore, the inner diameter d1 of the seed crystal cavity is selected as 2mm to 10mm, and the inner height of the seed crystal cavity is (0.8 to 4)×d1.

[0021] Furthermore, the inner diameter d2 of the expansion cavity is selected as (1.5~3)×d1, and the inner height of the expansion cavity is (0.8~4)×d2.

[0022] Furthermore, the inner diameter d3 of the reduced-diameter cavity is selected as (0.3~0.8)×d2, and the inner height of the reduced-diameter cavity is (0.8~4)×d3.

[0023] Furthermore, the diameter of the equal-diameter cavity is 2 inches to 8 inches (i.e., 50 mm to 200 mm); the height of the equal-diameter cavity is 20 mm to 50 mm.

[0024] Beneficial effects

[0025] This invention, through the rational design of gallium oxide growth technology, employs a crucible shell, seed crystal cavity, diameter expansion cavity, diameter reduction cavity, shoulder expansion cavity, and equal diameter cavity. This allows for phase separation between the gallium oxide crystal and the crucible wall during growth and cooling, reducing the likelihood of dislocation multiplication and twinning, lowering crystal dislocation density, and improving semiconductor chip performance. This crucible structure can be used to prepare gallium oxide single crystals of low dislocation density, such as cylindrical shapes, which possess uniform doping and can form substrate wafers with large (010) (001) main faces. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the crucible structure for growing gallium oxide single crystals using the VB method according to this utility model.

[0027] Figure 2 This is a schematic diagram of the crucible structure for growing gallium oxide single crystals using the VB method, from another perspective.

[0028] Figure 3This is a cross-sectional schematic diagram of the crucible structure for growing gallium oxide single crystals using the VB method according to this utility model.

[0029] Figure 4 This is a cross-sectional schematic diagram of multiple structures of a crucible structure for growing gallium oxide single crystals using the VB method according to this utility model.

[0030] Figure 5 This is a cross-sectional schematic diagram illustrating the multiple structures of a crucible structure for growing gallium oxide single crystals using the VB method according to this utility model.

[0031] The reference numerals are as follows: 01, Seed crystal cavity; 02, Expanded diameter cavity; 03, Reduced diameter cavity; 04, Expanded shoulder cavity; 05, Equal diameter cavity. Detailed Implementation

[0032] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0033] See Figures 1-5 As shown, this utility model provides a crucible structure for growing gallium oxide single crystals using the VB method. The crucible structure includes: a crucible shell, a seed crystal cavity 01, an expansion cavity 02, a reduction cavity 03, a shoulder expansion cavity 04, and a constant diameter cavity 05. The seed crystal cavity 01, expansion cavity 02, reduction cavity 03, shoulder expansion cavity 04, and constant diameter cavity 05 are provided inside the crucible shell. The seed crystal cavity 01 is located at one end of the crucible shell, and one end of the seed crystal cavity 01 is closed. The other end of the seed crystal cavity 01 is connected to the expansion cavity 02. The expansion cavity 02 is connected to the reduction cavity 03. The reduction cavity 03 is connected to the shoulder expansion cavity 04. The shoulder expansion cavity 04 is connected to the constant diameter cavity 05. The other end of the constant diameter cavity 05 is open.

[0034] Specifically, the expanded shoulder cavity 04 is a frustum-shaped expanded shoulder cavity, with the larger end of the expanded shoulder cavity 04 connected to the equal diameter cavity 05, and the smaller end of the expanded shoulder cavity 04 connected to the reduced diameter cavity 03; the expanded diameter cavity 02 is a cylindrical expanded diameter cavity, with a size larger than that of the reduced diameter cavity 03; and the seed crystal cavity 01 is a cylindrical seed crystal cavity, with a size smaller than that of the expanded diameter cavity 02.

[0035] The outer shell of the crucible is made of iridium, iridium alloy, or platinum-rhodium alloy, and the thickness of the outer shell is 0.1mm to 2mm.

[0036] Among them, at least one expansion cavity 02 is selected, at least one reduction cavity 03 is selected, and the number of expansion cavities 02 is equal to the number of reduction cavities 03. Each expansion cavity 02 and each reduction cavity 03 connected to it are set as a group, and each group of reduction cavities 03 is interconnected with the expansion cavities 02 of the adjacent group.

[0037] Among them, the included angle α of the expanded shoulder cavity 04 is selected to be 60°~150°; that is, the seed crystal cavity 01, the diameter expansion cavity 02, the diameter reduction cavity 03 and the constant diameter cavity 05 are all preferably cylindrical.

[0038] Specifically, the inner diameter d1 of the seed crystal cavity 01 is selected from 2mm to 10mm, and the inner height of the seed crystal cavity 01 is (0.8 to 4)×d1; the inner diameter d2 of the expanding cavity 02 is selected from (1.5 to 3)×d1, and the inner height of the expanding cavity 02 is (0.8 to 4)×d2; the inner diameter d3 of the reducing cavity 03 is selected from (0.3 to 0.8)×d2, and the inner height of the reducing cavity 03 is (0.8 to 4)×d3; the diameter of the equal-diameter cavity 05 is 2 inches to 8 inches (i.e., 50mm to 200mm); and the height of the equal-diameter cavity 05 is 20mm to 50mm.

[0039] The specific implementation of this utility model is as follows: During the gallium oxide crystal growth process, prepared gallium oxide raw materials are filled into a crucible, which is then placed in a VB growth furnace. Melting, seeding, growth, and cooling are performed according to a specific process. A seed crystal is placed in the seed crystal cavity, and the growth direction gradually extends along the seed crystal cavity to a cavity of uniform diameter. This reduced-diameter cavity serves to decrease dislocations and twin structures caused by thermal shock during initial seed crystal seeding, seed crystal defect inheritance, crucible wall parasites, and raw material decomposition during growth. Through one or more reductions in diameter, the dislocation density of gallium oxide single crystals can be significantly reduced, improving the yield of grown crystals.

[0040] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A crucible structure for growing gallium oxide single crystals using the VB method, characterized in that, The crucible structure includes: a crucible shell, a seed crystal cavity, an expansion cavity, a reduction cavity, a shoulder expansion cavity, and a constant diameter cavity. The seed crystal cavity, expansion cavity, reduction cavity, shoulder expansion cavity, and constant diameter cavity are provided inside the crucible shell. The seed crystal cavity is located at one end of the crucible shell and is closed at one end. The other end of the seed crystal cavity is connected to the expansion cavity. The expansion cavity is connected to the reduction cavity. The reduction cavity is connected to the shoulder expansion cavity. The shoulder expansion cavity is connected to the constant diameter cavity. The other end of the constant diameter cavity is open.

2. The crucible structure for growing gallium oxide single crystals using the VB method according to claim 1, characterized in that, The expanded shoulder cavity is selected as either a frustum-shaped or a truncated cone-shaped expanded shoulder cavity. The larger end of the expanded shoulder cavity is connected to the equal-diameter cavity, and the smaller end of the expanded shoulder cavity is connected to the reduced-diameter cavity.

3. The crucible structure for growing gallium oxide single crystals using the VB method according to claim 1, characterized in that, The expansion cavity is selected as either a prismatic or cylindrical expansion cavity.

4. The crucible structure for growing gallium oxide single crystals using the VB method according to claim 3, characterized in that, The size of the expanding cavity is larger than the size of the reducing cavity.

5. The crucible structure for growing gallium oxide single crystals using the VB method according to claim 1, characterized in that, The seed crystal cavity is selected as either a prismatic or cylindrical type.

6. The crucible structure for growing gallium oxide single crystals using the VB method according to claim 5, characterized in that, The size of the seed crystal cavity is smaller than the size of the expansion cavity.

7. The crucible structure for growing gallium oxide single crystals using the VB method according to claim 1, characterized in that, The crucible shell is made of iridium, iridium alloy, or platinum-rhodium alloy.

8. The crucible structure for growing gallium oxide single crystals using the VB method according to claim 1, characterized in that, The thickness of the crucible shell is selected from 0.1mm to 2mm.

9. The crucible structure for growing gallium oxide single crystals using the VB method according to claim 1, characterized in that, At least one expansion cavity and at least one reduction cavity are selected, and the number of expansion cavities is equal to the number of reduction cavities. Each expansion cavity and each reduction cavity connected to it are set as a group, and the reduction cavities in each group are interconnected with the expansion cavities in the adjacent group.

10. The crucible structure for growing gallium oxide single crystals using the VB method according to claim 2, characterized in that, The included angle α of the shoulder expansion cavity is selected to be 60° to 150°.

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