Method for growing gallium oxide single crystal by kyberysis method

Abstract

The present invention provides a method for growing gallium oxide single crystal by kyropoiesis, and the method for growing gallium oxide single crystal by kyropoiesis includes S01, furnace loading: loading gallium oxide raw material with a weight of M1 and a purity of 5N into a crucible, and placing the crucible with the raw material into a single crystal growth furnace; placing a plurality of heat preservation screens at intervals above the crucible; placing a seed crystal with a [010] crystal orientation on the top, and closing the single crystal growth furnace door; S02, heating and melting: heating and keeping the temperature until the gallium oxide raw material is completely melted; S03, seeding and growing; S04, cooling and crystal taking: after the growth is completed, the crystal temperature is lowered to room temperature and the crystal is taken out. In the method for growing gallium oxide single crystal by kyropoiesis provided by the present invention, after the heat preservation screen is set, the flow velocity of the volatile gas of the raw material can be blocked, the axial temperature gradient of the thermal field can be reduced and stabilized, and it is more conducive to optimizing the growth quality of gallium oxide crystal by kyropoiesis.

Description

Technical Field

[0001] The invention belongs to the technical field of semiconductor crystals, and in particular relates to a method for growing gallium oxide single crystals by a kyberyzing process. Background Art

[0002] Gallium oxide single crystal has a bandgap of 4.8eV and a Baliga figure of merit of more than 3000, and is known as the first ultra-wide bandgap semiconductor crystal that can be applied. There are various methods for growing gallium oxide single crystals, among which the guided mode method is certified as the mainstream growth method. However, the crystals grown by the guided mode method are in the shape of plates, the number of prepared substrates is limited, and the iridium metal used in this method is expensive and the amount of iridium is large, which hinders the industrialization process of gallium oxide single crystals. The bubble growth method adopted in this patent can grow columnar gallium oxide single crystals and obtain large-sized crystal surface substrates, which makes up for the disadvantage that the guided mode method cannot obtain large-sized (010) crystal surface gallium oxide substrates.

[0003] However, the existing kyberyzine gallium oxide growth method provides a relatively rough description of the overall growth process and does not provide a clear method for controlling the temperature gradient. Summary of the invention

[0004] The present invention provides a method for growing gallium oxide single crystals by a kyberyzing process, aiming to solve the technical problems existing in the above-mentioned background technology.

[0005] To achieve the above object, the technical solution adopted by the present invention is: to provide a method for growing gallium oxide single crystals by a kyberyzine method, comprising:

[0006] S01, loading the furnace: load gallium oxide raw material with a weight of M1 and a purity of 5N into the crucible, and place the crucible with the raw material into the single crystal growth furnace; place several heat preservation screens at intervals above the crucible; install a seed crystal with a

[010] crystal orientation on the top, and close the single crystal growth furnace door; evacuate to below 5Pa, and fill with high-purity CO2 at 0.7-1.3 atmospheres.

[0007] S02, heating the material: heating and keeping the temperature until the gallium oxide raw material is completely melted;

[0008] S03, seeding growth;

[0009] S04, cooling down and taking out the crystal: after the growth is completed, the crystal temperature is lowered to room temperature and the crystal is taken out.

[0010] It should be noted that a heat preservation cylinder is provided in the growth furnace, the crucible is placed in the heat preservation cylinder, a heat preservation screen is provided on the upper side of the crucible, connected to the heat preservation cylinder, and fixes the heat preservation screen.

[0011] In a possible implementation of the method for growing gallium oxide single crystals by the kyberyzine method provided by the present invention, in step S01, three heat preservation screens are placed above the crucible at intervals, each of the heat preservation screens is provided with an avoidance hole and a plurality of vents, the avoidance holes on the three heat preservation screens are arranged in an aligned manner to avoid the seed crystal; the vents on two adjacent heat preservation screens are arranged in a staggered manner; the vents on two adjacent heat preservation screens are arranged in a staggered manner. This effectively slows down the flow rate of the volatile gas of the raw material, blocks the emission of heat radiation, and stabilizes the thermal field; the size of the avoidance hole is slightly larger than the crystal size.

[0012] In a possible implementation of the method for growing gallium oxide single crystals by the kyberyzine process provided by the present invention, 9-16 vents are provided on the heat preservation screen, each vent has a diameter of 5-15 mm, and the interval between two adjacent heat preservation screens is 10-20 mm.

[0013] Specifically, the number of vents on the heat preservation screen and the diameter of the vents are set according to the actual diameter of the crystal. The larger the diameter of the crystal, the larger the diameter of the heat preservation screen, and the more vents are opened.

[0014] In a possible implementation of the method for growing gallium oxide single crystals by the kyvo method provided by the present invention, in step S01, the crystal orientation deviation of the seed crystal is ≤0.5°, and after closing the door of the single crystal growth furnace, the furnace is evacuated to below 5 Pa and filled with high-purity CO2 at 0.7-1.3 atmospheres.

[0015] It should be noted that the injection of carbon dioxide as a protective gas can effectively inhibit the high-temperature decomposition of gallium oxide.

[0016] In a possible implementation of the method for growing gallium oxide single crystals by the kyvo method provided by the present invention, in step S02, a heating rate of 100-150° C. / h is used to increase the temperature to 1850° C. and the temperature is kept for 5-8 hours until the gallium oxide raw material is completely melted.

[0017] In a possible implementation of the method for growing gallium oxide single crystals by the kyvo method provided by the present invention, in step S03, the seed crystal is passed through a heat preservation screen, lowered to 10-15 mm above the liquid surface, and kept warm for 20 min-1 h; the seed crystal is then lowered below the liquid surface and melted 10-20 mm; thereafter, the seed crystal is pulled upward at a pulling speed of 10-20 mm / h, and after it remains insoluble and does not grow, the pulling speed is reduced to 0.5-1.5 mm / h; finally, a cooling rate of 10-30°C / h is used to perform cooling growth.

[0018] In a possible implementation of the method for growing gallium oxide single crystals by the kyvo method provided by the present invention, in step S03, the weight of the crystal is recorded as M2. When the difference between M2 and M1 is 150-300 g, it indicates that the crystal growth is completed.

[0019] It should be noted that when the crystal growth is completed, a certain amount of material will remain in the crucible. When the weight difference between M2 and M1 is the weight of the remaining raw material in the crucible,

[0020] In a possible implementation of the method for growing gallium oxide single crystals by the kyvophyll method provided by the present invention, in step S03, during the crystal growth process, M2 continues to increase. After the crystal growth is completed, the temperature is increased by 10-20°C and kept warm for 0.5-1h, and the pulling speed is increased to 10-20mm / h. When the difference between M2 and M1 is 150-300g, and M2 changes from increasing to decreasing, it indicates that the crystal has left the crucible.

[0021] It should be noted that during the crystal growth process, the number of crystals continues to increase, so the weight will continue to increase. However, when it leaves the crucible, due to the effect of surface tension, M2 will decrease instantaneously after the crystal is completely separated from the crucible. At this time, it means that the crystal has left the crucible, thereby effectively reducing the cracking rate of gallium oxide when it is cooled.

[0022] In a possible implementation of the method for growing gallium oxide single crystals by the kyvo method provided by the present invention, in step S06, when a medium-resistance or high-resistance crystal is needed, the temperature is lowered to 1000°C at a cooling rate of 100-150°C / h, kept at a constant temperature for 3-5h, and then cooled to room temperature at 200-300°C / h to take out the crystal.

[0023] In a possible implementation of the method for growing gallium oxide single crystals by the kyberyzine method provided by the present invention, in step S06, when a low-resistance crystal is needed, the temperature is lowered to 1000°C at a cooling rate of 100-150°C / h, N2 is filled for annealing, the low-resistance resistivity is maintained constant for annealing, the temperature is lowered to room temperature, and the crystal is taken out.

[0024] The method for growing gallium oxide single crystals by the kyropoiesis method provided by the present invention has the following beneficial effects: compared with the prior art, the method for growing gallium oxide single crystals by the kyropoiesis method provided by the present invention is provided with a plurality of heat preservation screens on the upper side of the crucible, and the gallium oxide raw material volatilizes severely after melting. After the heat preservation screens are provided, the flow rate of the volatile gas of the raw material can be blocked, the axial temperature gradient of the thermal field can be reduced and stabilized, and it is more conducive to optimizing the growth quality of gallium oxide crystals by the kyropoiesis method; and it can block thermal radiation, reduce the axial temperature gradient, and make the axial temperature gradient of the thermal field easier to control, thereby improving the crystallization rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 A schematic diagram of the main structure of a crucible, a heat preservation cylinder and a heat preservation screen in a growth furnace used in a method for growing a gallium oxide single crystal by a kyvophyll method provided in an embodiment of the present invention;

[0026] Figure 2 A schematic diagram of a top view of a heat preservation screen used in a method for growing gallium oxide single crystals by a kyberyzing method provided in an embodiment of the present invention;

[0027] Description of reference numerals:

[0028] 11. Crucible; 12. Insulation tube; 13. Insulation screen; 131. Avoidance hole; 132. Ventilation hole. DETAILED DESCRIPTION

[0029] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0030] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present application and its application or use. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0031] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0032] Unless otherwise specifically stated, the relative arrangement, numerical expressions and numerical values ​​of the parts and steps set forth in these embodiments do not limit the scope of the application. Meanwhile, it should be understood that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to actual proportional relationships. The technology, methods and equipment known to those of ordinary skill in the relevant art may not be discussed in detail, but in appropriate cases, the technology, methods and equipment should be considered as a part of the specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, and therefore, once a certain item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

[0033] In the description of the present application, it should be understood that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction, and therefore cannot be understood as limiting the scope of protection of the present application; the directional words "inside and outside" refer to the inside and outside relative to the contours of each component itself.

[0034] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" may include both "above" and "below". The device may also be positioned in other different ways, and the spatially relative descriptions used here are interpreted accordingly.

[0035] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of this application.

[0036] Please also read Figure 1 to Figure 2 Now, the method for growing gallium oxide single crystals by the kyvo method provided by the present invention is described.

[0037] Embodiment 1:

[0038] A method for growing a gallium oxide single crystal by a kyberyzing method comprises the following steps:

[0039] S01, furnace loading: load gallium oxide raw material weighing M1=1500g, purity 5N, into the crucible, put the crucible with raw material into the single crystal growth furnace; place 3 heat preservation screens above the crucible, with 10 vents on the heat preservation screen, each vent has a diameter of 8mm, and the interval between two adjacent heat preservation screens is 10mm; install a seed crystal with

[010] crystal orientation at the top, with the crystal orientation deviation of the seed crystal ≤0.5°, and close the single crystal growth furnace door; after closing the single crystal growth furnace door, evacuate to below 5Pa, and fill with 0.7 atmospheres of high-purity CO2;

[0040] S02, heating the material: heating up to 1850°C at a rate of 100°C / h, keeping the temperature for 5h until the gallium oxide raw material is completely melted;

[0041] S03, seeding growth: pass the seed crystal through the heat preservation screen, lower it to 10mm above the liquid surface, and keep it warm for 20min; then lower the seed crystal to below the liquid surface and melt it 10mm; then, use a pulling speed of 10mm / h to pull the seed crystal upward, and after it remains undissolved and ungrown, reduce the pulling speed to 0.5mm / h; finally, use a cooling rate of 10℃ / h to carry out cooling growth; record the crystal weight as M2, when the difference between M2 and M1 is 150g, it indicates that the crystal growth is complete; then, increase the temperature by 10℃, keep warm for 0.5h, and increase the pulling speed to 10mm / h, until M2 changes from rising to falling, indicating that the crystal is out of the crucible;

[0042] S04, cooling and crystal removal: cooling to 1000°C at a cooling rate of 100°C / h, keeping the temperature constant for 3h, then cooling to room temperature at a cooling rate of 200-300°C / h, and taking out the crystal.

[0043] The method of Example 1 was performed 100 times to measure the yield and cracking rate of 100 crystals. Crystallization rate = (number of qualified crystals / total number of crystals) × 100%; cracking rate = (number of cracked crystals / total number of crystals) × 100%. The crystallization rate of this example is 85%, and the cracking rate is 15%.

[0044] Embodiment 2:

[0045] A method for growing a gallium oxide single crystal by a kyberyzing method comprises the following steps:

[0046] S01, furnace loading: load gallium oxide raw material weighing M1=1750g, purity 5N, into the crucible, put the crucible with raw material into the single crystal growth furnace; place 3 heat preservation screens above the crucible, with 13 vents on the heat preservation screen, each vent has a diameter of 10mm, and the interval between two adjacent heat preservation screens is 15mm; install a seed crystal with

[010] crystal orientation at the top, with the seed crystal crystal orientation deviation ≤0.5°, and close the single crystal growth furnace door; after closing the single crystal growth furnace door, evacuate to below 5Pa, and fill with 1.0 atmosphere of high-purity CO2;

[0047] S02, heating the material: heating at a rate of 125°C / h to 1850°C, keeping the temperature for 6.5h until the gallium oxide raw material is completely melted;

[0048] S03, seeding growth: pass the seed crystal through the heat preservation screen, lower it to 12mm above the liquid surface, and keep it warm for 40min; then lower the seed crystal to below the liquid surface and melt 15mm; then, use a pulling speed of 15mm / h to pull the seed crystal upward, and after it remains insoluble and not growing, reduce the pulling speed to 1.0mm / h; finally, use a cooling rate of 20℃ / h to carry out cooling growth; record the crystal weight as M2, when M2 differs from M1 by 150-300g, it indicates that the crystal growth is complete; then, increase the temperature by 15℃, keep warm for 0.8h, and increase the pulling speed to 15mm / h, until M2 changes from increasing to decreasing, indicating that the crystal is out of the crucible;

[0049] S04, cooling and crystal removal: cooling to 1000°C at a rate of 150°C / h, keeping the temperature constant for 5h, then cooling to room temperature at a rate of 300°C / h, and taking out the crystal.

[0050] The method of Example 2 was performed 100 times to measure the yield and cracking rate of 100 crystals. Crystallization rate = (number of qualified crystals / total number of crystals) × 100%; cracking rate = (number of cracked crystals / total number of crystals) × 100%. The crystallization rate of this example is 90%, and the cracking rate is 10%.

[0051] Embodiment three:

[0052] A method for growing a gallium oxide single crystal by a kyberyzing method comprises the following steps:

[0053] S01, furnace loading: load gallium oxide raw material weighing M1=2000g, purity 5N, into the crucible, put the crucible with raw material into the single crystal growth furnace; place 3 heat preservation screens above the crucible, with 15 vents on the heat preservation screen, each vent has a diameter of 12mm, and the interval between two adjacent heat preservation screens is 20mm; install a seed crystal with

[010] crystal orientation at the top, with the seed crystal crystal orientation deviation ≤0.5°, and close the single crystal growth furnace door; after closing the single crystal growth furnace door, evacuate to below 5Pa, and fill with high-purity CO2 at 1.3 atmospheres;

[0054] S02, heating the material: heating at a rate of 150°C / h to 1850°C, keeping the temperature for 8h until the gallium oxide raw material is completely melted;

[0055] S03, seeding growth: pass the seed crystal through the heat preservation screen, lower it to 15mm above the liquid surface, and keep it warm for 1h; then lower the seed crystal to below the liquid surface and melt it 20mm; then, use a pulling speed of 20mm / h to pull the seed crystal upward, and after it remains insoluble and does not grow, reduce the pulling speed to 1.5mm / h; finally, use a cooling rate of 30℃ / h to carry out cooling growth; record the crystal weight as M2, when M2 differs from M1 by 300g, it indicates that the crystal growth is complete; then, increase the temperature by 20℃, keep it warm for 1h, and increase the pulling speed to 20mm / h, until M2 changes from increasing to decreasing, indicating that the crystal is out of the crucible;

[0056] S04, cooling and crystal removal: cooling to 1000°C at a cooling rate of 150°C / h, filling with N2 for annealing, maintaining low-resistance resistivity for constant annealing, cooling to room temperature, and taking out the crystal.

[0057] The method of Example 3 was performed 100 times to measure the yield and cracking rate of 100 crystals. Crystallization rate = (number of qualified crystals / total number of crystals) × 100%; cracking rate = (number of cracked crystals / total number of crystals) × 100%. The crystallization rate of this example is 92%, and the cracking rate is 8%.

[0058] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for growing gallium oxide single crystals by the kyberysis method, characterized in that: include: S01, furnace loading: Load gallium oxide raw material with a weight of M1 and a purity of 5N into the crucible, and place the crucible with the raw material into the single crystal growth furnace; place three heat preservation screens at intervals above the crucible, each of which is provided with an avoidance hole and a plurality of vents, and the avoidance holes on each of the heat preservation screens are aligned to avoid the seed crystal; the vents on two adjacent heat preservation screens are staggered; a seed crystal with a [010] crystal orientation is placed on the top, and the single crystal growth furnace door is closed; S02, heating the material: heating and keeping the temperature until the gallium oxide raw material is completely melted; S03, seeding growth; S04, cooling down and taking out the crystal: after the growth is completed, the crystal temperature is lowered to room temperature and the crystal is taken out.

2. The method for growing gallium oxide single crystals by the kyvo method according to claim 1, characterized in that: The heat preservation screen is provided with 9-16 ventilation holes, each of which has a diameter of 5-15 mm, and the interval between two adjacent heat preservation screens is 10-20 mm.

3. The method for growing gallium oxide single crystals by the kyvo method according to claim 1, characterized in that: In step S01, the crystal orientation deviation of the seed crystal is ≤0.5°, and after closing the door of the single crystal growth furnace, the furnace is evacuated to below 5 Pa and filled with high-purity CO2 at a pressure of 0.7-1.3 atmospheres.

4. The method for growing gallium oxide single crystals by the kyvo method according to claim 1, characterized in that: In step S02, the temperature is raised to 1850°C at a rate of 100-150°C / h and kept at this temperature for 5-8h until the gallium oxide raw material is completely melted.

5. The method for growing gallium oxide single crystals by the kyvo method according to claim 1, characterized in that: In step S03, the seed crystal is passed through a heat-insulating screen and lowered to 10-15 mm above the liquid surface, where it is kept warm for 20 min-1 h. The seed crystal is then lowered to below the liquid surface and melted 10-20 mm. Afterwards, the seed crystal is pulled upward at a pulling speed of 10-20 mm / h, and after it remains insoluble and does not grow, the pulling speed is reduced to 0.5-1.5 mm / h. Finally, a cooling rate of 10-30°C / h is used for cooling growth.

6. The method for growing gallium oxide single crystals by the kyvo method according to claim 1, characterized in that: In step S03, the crystal weight is recorded as M2. When the difference between M2 and M1 is 150-300 g, it indicates that the crystal growth is completed.

7. The method for growing gallium oxide single crystals by the kyvo method according to claim 6, characterized in that: In step S03, during the crystal growth process, M2 continues to increase. After the crystal growth is completed, the temperature is raised by 10-20°C and kept for 0.5-1h. The pulling speed is increased to 10-20mm / h until M2 decreases, indicating that the crystal is out of the crucible.

8. The method for growing gallium oxide single crystals by the kyvo method according to claim 1, characterized in that: In step S04, the temperature is lowered to 1000°C at a cooling rate of 100-150°C / h, kept constant for 3-5h, and then lowered to room temperature at a cooling rate of 200-300°C / h to take out the crystal.

9. The method for growing gallium oxide single crystals by the kyvo method according to claim 1, characterized in that: In step S04, the temperature is lowered to 1000°C at a cooling rate of 100-150°C / h, N2 is filled for annealing, and the low-resistance resistivity is maintained for annealing, and the temperature is lowered to room temperature, and the crystal is taken out.

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