CN104878451B - Nitride single crystal growth device - Google Patents

Abstract

The invention discloses a nitride single crystal growth device, which comprises a reaction kettle, wherein a solution is filled in the reaction kettle, a seed crystal template is arranged at the bottom in the reaction kettle, a solution flow direction guiding device which is completely immersed in the solution is arranged in the reaction kettle, heaters are arranged around the bottom surface and the side wall of the reaction kettle, the solution flow direction guiding device is a hollow pipe body, the bottom of the hollow pipe body is fixed at the bottom surface of the reaction kettle, and a through hole is arranged at the lower part of the side wall of the hollow pipe body. The invention effectively overcomes the disadvantages of the traditional liquid phase method such as N vacancy, non-uniform crystallization, slow growth speed and the like in the process of growing the nitride single crystal, and improves the quality of the crystalline material.

Description

A nitride single crystal growth device

technical field

The invention relates to the technical field of semiconductors, in particular to a nitride single crystal growth device.

Background technique

In recent years, group 3B nitrides have great application value in the field of luminescence due to their excellent luminescence properties. As one of the representative materials of group 3B nitrides, gallium nitride has the characteristics of wide band gap, high thermal conductivity, and good chemical stability, and has broad prospects in high-frequency and high-power devices and other application fields.

At present, the main method for commercially preparing gallium nitride semiconductor materials is hydride vapor phase epitaxy (HVPE). Although the growth rate is relatively high, the crystal quality still needs to be further improved. In order to improve the crystal quality, researchers are committed to studying other gallium nitride single crystal growth methods, such as high temperature and high pressure method (HPNS), sodium flow method (Na Flux) and ammothermal method (Ammothermal growth). Compared with other methods, the growth conditions of the sodium flow method are relatively mild and the crystal quality is high, so it has a great application prospect.

The latest research shows that through local heating, a large temperature difference is generated between different regions inside the solution, and thermal convection can be generated between different temperature regions. However, due to local heating, the flow direction of the solution is not qualitative, that is, the convection is infinite. Ordered, this disordered thermal convection is difficult to grow high-quality GaN single crystals.

Contents of the invention

The technical problem to be solved by the present invention is to provide a nitride single crystal growth device, which can guide the directional flow of the solution, regularize the disordered heat convection, and generate orderly and controllable heat convection.

In order to solve the above technical solutions, the present invention takes the following technical solutions:

A nitride single crystal growth device, including a reaction kettle, the reaction kettle is filled with a solution, the bottom of the reaction kettle is provided with a seed crystal template, and the inside of the reaction kettle is provided with a solution completely immersed in the solution to guide the directional flow of the solution Flow guiding device, heaters are installed around the bottom and side walls of the reactor.

The solution flow guiding device is a hollow pipe body, the bottom of the hollow pipe body is fixed on the bottom surface of the reaction kettle, and the lower part of the side wall of the hollow pipe body is provided with a conduction hole.

Conducting holes are symmetrically arranged on the side wall of the hollow tube body along the axis of the hollow tube body.

The shape of the hollow tube includes, but is not limited to, a round tube, a square tube, and a truncated cone.

The shape of the through hole on the hollow tube body includes but not limited to circle, square, ellipse, and prism.

The heater arranged around the side wall of the reaction kettle includes an upper heater and a lower heater distributed up and down.

The heating methods of the heater include, but are not limited to, resistance heating, radio frequency heating, and infrared heating.

The seed crystal template is a sapphire substrate, a silicon carbide substrate, a silicon substrate or a silicon germanium substrate; or a corresponding nitride self-supporting substrate; or a nitride composite substrate grown on a heterogeneous substrate ; The substrate is c-plane, non-polar plane or semi-polar plane.

The seed crystal template is placed horizontally; or placed vertically; or placed at a certain angle to the horizontal direction.

The present invention regulates the disordered heat convection by setting the solution flow guide device in the reaction kettle, generates orderly and controllable heat convection, and realizes the orderly solute without stirring blades and complicated heating systems The flow drives the high concentration of N on the upper surface of the solution in the reactor to fully participate in the reaction. The formed crystal has less defects, uniform thickness, and the growth rate is effectively improved. And has the following advantages.

1. Orderly convection is formed, so that the high concentration of N on the upper surface of the solution can fully enter the solution to participate in the reaction, reducing defects such as N vacancies in the crystal, and the crystal quality is high.

2. Make the solution form a controllable convection, which can adjust the flow rate and flow direction, which is beneficial to reduce the crystallization phenomenon on the crystal surface and improve the uniformity of crystal thickness.

3. Orderly and controllable convection increases the crystal growth rate on the one hand, and reduces the polycrystalline layer at the gas-liquid interface on the other hand, effectively improving the utilization rate of reactants.

4. The flow guide device is easy to install, with variable shape and adjustable parameters, which can meet various actual production requirements and make corresponding adjustments.

Description of drawings

Accompanying drawing 1 is a schematic diagram of the solution flow state of Embodiment 1 of the present invention;

Accompanying drawing 2 is a schematic diagram of the setting structure of the seed crystal template in Embodiment 1 of the present invention;

Accompanying drawing 3 is the schematic diagram of the three-dimensional structure of the solution flow guide device of Embodiment 1 of the present invention;

Accompanying drawing 4 is the schematic diagram of the solution flow state of the second embodiment of the present invention;

Accompanying drawing 5 is the three-dimensional structure diagram of the solution flow guide device of the second embodiment of the present invention;

Accompanying drawing 6 is another implementation structure schematic diagram of the solution guiding device of the present invention;

Accompanying drawing 7 is another implementation structure schematic diagram of the solution guiding device of the present invention;

Accompanying drawing 8 is the structural schematic diagram of another implementation of the solution guiding device of the present invention.

detailed description

In order to facilitate the understanding of those skilled in the art, the present invention will be further described below in conjunction with the drawings and specific embodiments.

As shown in Figures 1 and 2, the present invention discloses a nitride single crystal growth device, including a reactor, the reactor is filled with a solution, the bottom of the reactor is provided with a seed crystal template, and the inside of the reactor is provided with a complete The guiding solution immersed in the solution flows to the guiding device, and heaters are arranged around the bottom surface and the side wall of the reaction kettle. Wherein, a plurality of heaters can be arranged around the side wall of the reaction kettle, such as at least two heaters arranged from top to bottom, and the two heaters are usually arranged at intervals. The heater can heat the side of the reactor as a whole; it can also be evenly distributed on the side of the reactor to form localized heating; it can also be distributed up and down on the side of the reactor to form regionalized heating distributed up and down. The heating methods of the heater include, but are not limited to, resistance heating, radio frequency heating, and infrared heating. The heating temperature of the heater at the bottom of the reaction kettle and the heater at the side wall of the reaction kettle can be the same or different.

The solution flow guiding device is a hollow pipe body, the bottom of which is fixed on the bottom surface of the reaction kettle, and the lower part of the side wall of the hollow pipe body is provided with a plurality of conduction holes. And it is arranged symmetrically, that is, the conduction hole is symmetrically arranged on the side wall of the hollow pipe body along the axis of the hollow pipe body. The hollow tube body can be in the shape of a circular tube, a square tube or a truncated cone, or other shapes, and it can also be narrow in the middle and wide in the upper and lower parts, or wide in the middle and narrow in the upper and lower parts, or other shapes. The form is not limited here. The shape of the via hole can also be flexibly set according to actual needs, for example, the via hole is circular, square, elliptical, or prismatic, or other shapes. The different shapes of the hollow tube can regulate the flow direction of the solution, and the shape and size of the through hole can control the flow rate of the solution into the hollow tube, and controllable adjustment of the crystal growth. There are no special restrictions on the height and size of the hollow tube body and the size of the via hole. They can be flexibly selected and set according to the size of the inner space of the reactor and the filling degree of the solution, and according to the crystal growth requirements.

In addition, the seed crystal template is a sapphire substrate, a silicon carbide substrate, a silicon substrate or a silicon germanium substrate; or a corresponding nitride free-standing substrate; or a nitride composite substrate grown on a heterogeneous substrate ; The substrate is c-plane, non-polar plane or semi-polar plane. The seed crystal template is placed horizontally; or placed vertically; or placed at a certain angle to the horizontal direction.

The following will be described with specific embodiments.

Embodiment 1, as shown in Figures 1 to 3, the solution flow guide device 130 is a hollow tube body with a narrow middle and wider upper and lower parts, and the heater 121 at the bottom of the reaction kettle 100 is in a high-temperature heating state, preferably at a temperature of 890°C ; The heater 122 around the reactor 100 is set as a lower temperature heater (relative to the heater at the bottom of the reactor), preferably with a temperature of 880°C.

The bottom of the reaction kettle is high temperature, the bottom of the solution center forms a high-temperature zone A, and the top of the solution center forms a low-temperature zone B, and a temperature difference occurs between the high-temperature zone and the low-temperature zone, driving the solution 110 to form heat convection, and the convection direction is from the high-temperature zone A to the low-temperature zone B. Affected by the solution flow guiding device 130 , in convective state, the solution 110 flows along the inner surface of the solution flowing guiding device 130 , and flows to the side edge area of the reaction vessel 100 at the top opening of the solution flowing guiding device 130 . At the same time, at the bottom edge of the reaction kettle 100 , the solution diffuses through the conduction hole 131 and flows into the solution to flow into the guiding device 130 , forming an orderly rectification and convection flow 111 of the solution.

Presetting the size of the through hole 131 can regulate the flow rate of the solution flowing into the guiding device 130 to regulate the flow rate of the solution rectifier 111 and controllably adjust the crystal growth. Presetting the height, width, shape and other parameters of the solution flow guide device 130 can regulate the flow direction of the solution rectifier 111 and controllably adjust the crystal growth. In this embodiment, preferably, the through hole 131 has a diameter of 5mm, the solution flow direction guide device 130 has a height of 60mm, a middle neck width of 16mm, a bottom width of 35mm, and a top width of 30mm, and is shaped like a vase.

The seed template 140 can be placed horizontally at the bottom area of the solution flow guiding device 130, or can be hung vertically at the center and surroundings of the solution flowing guiding device 130, as shown in FIG. 2 . The solution rectification and convection flow 111 evenly flows on the surface of the seed crystal template 140, driving the high concentration of N on the surface to fully participate in the reaction, and the formed crystal has fewer defects, uniform thickness, and effectively increases the growth rate. At the same time, reducing the high concentration of N on the surface of the gas-liquid interface is beneficial to reducing the polycrystalline layer.

Embodiment 2, as shown in Figures 4 and 5, the difference between Embodiment 2 and Embodiment 1 lies in the shape of the solution flow guide device and the arrangement of heaters around the side wall of the reaction kettle. An upper heater 222 and a lower heater 223 are arranged at intervals along the vertical direction around the side wall of the reactor 100 . The heater 221 at the bottom of the reactor 100 is set to the first high-temperature heating state, preferably at a temperature of 890°C; the upper heater 222 around the reactor is set to the second high-temperature heating device, preferably at a temperature of 880°C; the lower heater 223 around the reactor is set to It is a low-temperature heating device, preferably with a temperature of 875°C.

The bottom of the reaction kettle is high temperature, the bottom of the solution center forms a high-temperature zone A, and the top of the solution center forms a low-temperature zone B. A temperature difference is formed between the high-temperature zone and the low-temperature zone, and the temperature difference drives the solution to form thermal convection, and the convection direction is from the high-temperature zone A to the low-temperature zone B. Affected by the solution flow guiding device 230 , the solution 110 flows along the inner surface of the solution flowing guiding device 230 in a convective state, and flows to the side edge area of the reaction vessel 100 at the top opening of the solution flowing guiding device 230 . In the side edge area of the reaction kettle 100, the upper part has a high temperature of 880°C and the lower part has a lower temperature of 875°C. The solution convectively flows from the upper high temperature region to the lower low temperature region (the bottom edge of the reaction kettle 100). 231 diffuses into the solution and flows to the guiding device 230 to form an orderly rectification and convection flow 211 of the solution.

Presetting the size of the through hole 231 can regulate the flow rate of the solution flowing into the guiding device 230 to regulate the flow rate of the solution rectifier 211 and controllably adjust the crystal growth. Presetting parameters such as the height, width, and shape of the solution flow guide device 230 can regulate the flow direction of the solution rectifier 211 and controllably adjust the crystal growth. In this embodiment, preferably, the diameter of the through hole 231 is 4 mm, the height of the solution flow guide device is 55 mm, the width of the middle neck is 12 mm, the width of the bottom is 35 mm, and the width of the top is 35 mm, and the shape is drum-shaped.

In addition, for the arrangement of the solution flow guide device, as shown in Figure 6, the solution flow guide device is in the shape of a vase (narrow in the middle and wide at both ends), and the through hole at the bottom is a square through hole. Alternatively, as shown in FIG. 7 , the solution flow guide device is cylindrical, and the conduction hole at the bottom is a circular through hole. Alternatively, as shown in Figure 8, the solution flow guide device is in the shape of a vase with ears, and the conduction hole at the bottom is a circular through hole.

It should be noted that the above description is not a limitation to the technical solution of the present invention, and any obvious replacements are within the protection scope of the present invention without departing from the inventive concept of the present invention.

Claims (5)

1. being filled with solution in a kind of growing nitride single crystal device, including reactor, the reactor, reactor inner bottom part is provided with Crystal seed template, it is characterised in that the reactor is internally provided with the guiding solution directed flow being totally submerged in the solution Solution flows to guide device, and reactor bottom surface and lateral wall circumference are all provided with having heaters, and it is hollow that the solution, which flows to guide device, Body, the hollow tube bottom is fixed on reactor bottom surface, and the hollow tube lower sidewall is provided with via hole.

2. growing nitride single crystal device according to claim 1, it is characterised in that edge on the side wall of the hollow tube The axisymmetrical of the hollow tube is provided with via hole, and hollow tube is shaped as circular tube shaped, square tube type or frustum, via hole Be shaped as circular, square, oval or prismatic.

3. growing nitride single crystal device according to claim 2, it is characterised in that the reactor lateral wall circumference is set Heater include the upper heater that is distributed up and down and lower heater.

4. according to growing nitride single crystal device according to any one of claims 1 to 3, it is characterised in that the crystal seed mould Plate is Sapphire Substrate, silicon carbide substrates, silicon substrate or silicon-Germanium substrate；Either corresponding nitride self-supported substrate；Or Person is the nitride compound substrate being grown in foreign substrate；The substrate is c faces, non-polar plane or semi-polarity face.

5. a kind of growing nitride single crystal device according to claims 4, it is characterised in that：The crystal seed template is level Place；It is either vertical to place.