CN102304763B - Continuous high temperature chemical vapor deposition (HTCVD) method silicon carbide crystal growing device - Google Patents

Abstract

The invention relates to a continuous high temperature chemical vapor deposition (HTCVD) method silicon carbide crystal growing device. The device comprises a main chamber, a moveable tray, a fixed tray, a first auxiliary chamber and a second auxiliary chamber, wherein the main chamber is a hollow cylinder and used for providing a vacuum environment for crystal growth; a tail gas pipeline radially passes through the main chamber; a source gas pipeline is communicated with the lower part of the tail pipeline; the moveable tray is positioned in the main chamber and above the source gas pipeline; the fixed tray is positioned in the main chamber and above the moveable tray; the first auxiliary chamber is used for providing a vacuum buffer environment and provides a sample to the main chamber under the environment; the first auxiliary chamber is positioned on one side of the main chamber and is communicated with the main chamber; a first gate is arranged between the main chamber and the first auxiliary chamber; a second auxiliary chamber is used for providing a vacuum buffer environment and taking out the sample from the main chamber under the environment; the second auxiliary chamber is arranged on the other side of the main chamber and is communicated with the main chamber; a second gate is arranged between the main chamber and the second auxiliary chamber; and the first auxiliary chamber and the second auxiliary chamber are isolated from the main chamber respectively through the first gate and the second gate.

Description

Continuous HTCVD silicon carbide crystal growth device

technical field

The present invention relates to the field of semiconductor technology, in particular to a continuous high temperature chemical vapor deposition (High Temperature Chemical Vapor Deposition, HTCVD) silicon carbide crystal growth device or a halide chemical vapor deposition (Halogen Chemical Vapor Deposition, HCVD) silicon carbide crystal growth device.

Background technique

Silicon carbide (SiC) is the third-generation semiconductor material developed after the first-generation semiconductor materials silicon (Si), germanium (Ge) and the second-generation semiconductor material gallium arsenide (GaAs). Since SiC has the characteristics of three times the wide bandgap of Si, ten times the high critical breakdown electric field of Si, three times the high thermal conductivity of Si, and twice the high carrier saturation concentration of Si, it is widely used in military and aerospace applications. It has superior application value in high temperature, high frequency, high power power electronics and optoelectronic devices in the field, and gradually replaces the existing silicon and gallium arsenide based power electronic devices, becoming the next generation of semiconductor basic materials.

In terms of the application of semiconductor lighting substrate materials, the thermal conductivity of silicon carbide is ten times that of sapphire, which can better solve the technical problems of heat dissipation for high-power semiconductor lighting devices; in addition, silicon carbide materials can be used as substrates for vertical structure light emitters In theory, the same material can double the luminous efficiency and save almost half the cost. It has become a general trend to replace sapphire with silicon carbide as the substrate material of light-emitting diodes (LEDs). Therefore, silicon carbide wafers have important applications and broad prospects in the fields of microelectronics, power electronics, and semiconductor lighting devices.

At present, SiC wafers are generally prepared by the physical vapor transport (PVT) method. The PVT method itself consumes a lot of power and has a small production capacity. As a result, the current price of silicon carbide wafers in the market is high and the supply is small, which seriously restricts the development of related downstream industries.

High-temperature chemical vapor deposition (HTCVD) is also used to prepare SiC wafers. FIG. 1 shows a crystal growth device used in the prior art to prepare SiC wafers by HTCVD. As shown in FIG. 1 , the crystal growth device uses silicon-containing semiconductor gas (such as SiCl ₄ ) and carbon-containing semiconductor gas (C ₃ H ₈ ), and reacts at high temperature to synthesize SiC, thereby forming SiC on the seed crystal 102 crystal ingot, and then form a SiC substrate through wafer processing; among them, 101 is the temperature detection window, 102 is the seed crystal, 103 is the furnace chamber, 104 is the insulation layer of the crystal growth device, 105 is the gas inlet of the inner layer, and 106 is the outer Layer gas inlet, 107 is tail gas outlet. In view of the low cost of raw materials, moderate energy consumption, and large output, the HTCVD method can meet the needs of the current LED device industry development, and is also suitable for growing P-type and high-purity semi-insulating silicon carbide wafers for high-power power electronics industry .

However, with the rapid development and huge demand of the industrialization of new-generation LED devices, as well as the soaring cost of resources and the substantial increase in energy consumption and environmental protection costs, there is no doubt that higher requirements are placed on the preparation of SiC wafers. The traditional silicon carbide crystal growth device usually only grows one crystal ingot (crystal rod) per furnace, and the general growth device is intermittent, that is, the raw material is heated and grown after being loaded into the furnace, and the temperature is lowered after the growth is completed, and it cannot be started until room temperature. The ingot is taken out of the furnace; relatively speaking, the growth efficiency is low, which cannot meet the huge demand of industrial scale development.

With the increasing demand for a new generation of LED devices at home and abroad, the requirements for the industrialization of the new generation of LED devices are becoming more and more urgent; it is urgent to provide a new type of silicon carbide crystal growth device so that it can be used without cooling down and shutting down the furnace. Continuous production of crystal ingots under the circumstances, in order to improve efficiency and reduce costs, to meet the needs of large-scale production of SiC substrates.

Contents of the invention

In order to solve the above problems, the present invention provides a CVD SiC crystal growth device, which can continue to produce the next crystal ingot without cooling down and shutting down the furnace, thereby improving efficiency and reducing costs.

The invention provides a continuous HTCVD silicon carbide crystal growth device, comprising:

A main chamber, which is a cylindrical hollow body, is used to provide a vacuum environment for crystal growth. The radial direction of the main chamber passes through a tail gas pipeline, and a source gas pipeline is opened below the tail gas pipeline;

a movable tray located in the main chamber above the source gas line;

a fixed tray, located in the main chamber, above the movable tray;

A first auxiliary chamber is used to provide a vacuum buffer environment and provide samples to the main chamber under this environment. The first auxiliary chamber is located on one side of the main chamber and communicates with the main chamber. There is a first gate between the chamber and the first auxiliary chamber;

A second auxiliary chamber is used to provide a vacuum buffer environment, and take out samples to the main chamber under this environment, the second auxiliary chamber is located on the other side of the main chamber, communicates with the main chamber, and There is a second gate between the main chamber and the second auxiliary chamber;

Wherein the first and second auxiliary chambers are respectively isolated from the main chamber by first and second gates.

In the continuous crystal growth device provided by the present invention, the thermal insulation wall connected with the auxiliary cavity in the main growth chamber is movable, and when growing crystal ingots (rods), the inner wall is formed together with the fixed thermal insulation wall to play the role of thermal insulation and maintaining the airflow field , when the growth is completed or interrupted, the movable insulation wall settles to a certain height, so that the magnetic rod in the auxiliary chamber can send and take the movable tray located in the main growth chamber, so as to complete the continuous production without cooling down and shutting down the furnace.

Description of drawings

The technical solution of the present invention will be described in further detail below in conjunction with the accompanying drawings and specific embodiments, wherein:

Fig. 1 shows the crystal growth device used in the preparation of SiC wafer by HTCVD method in the prior art;

Fig. 2 shows the side view of an embodiment of the continuous crystal growth device provided by the present invention;

Fig. 3 shows the top view of an embodiment of the continuous crystal growth device provided by the present invention;

Fig. 4 shows the sectional view of continuous type crystal growth device shown in Fig. 3 along AA ';

Fig. 5 shows a cross-sectional view of the continuous crystal growth device shown in Fig. 3 along BB'.

Detailed ways

Exemplary embodiments of the present invention will be described below with reference to the accompanying drawings. For the sake of clarity and brevity, actual embodiments are not limited to the technical features described in the specification. It should be understood, however, that in improving any one of the actual embodiments described, multiple embodiment-specific decisions must be made to achieve the improver's specific goals, for example, compliance with industry-related and business-related constraints, described Limits vary from embodiment to embodiment. Moreover, it should be understood that the effects of the aforementioned improvements, even if very complex and time-consuming, are still routine technical means for those skilled in the art who are aware of the benefits of the present invention.

Please refer to shown in Fig. 2 to Fig. 5, as Fig. 2, continuous type crystal growth device comprises: main chamber 1, is a cylindrical hollow body, is used to provide the vacuum environment of crystal growth, the diameter of this main chamber 1 Pass through a tail gas pipeline 3, pass into a source gas pipeline 11 below the tail gas pipeline 3; And grow crystals in this chamber; Movable tray 4 (Fig. The top of the source gas pipeline 11; the fixed tray 5 is located in the main chamber 1, above the movable tray 4; the first auxiliary chamber 7 is used to provide a vacuum buffer environment, and in this environment to the main chamber The chamber 1 provides samples, the first auxiliary chamber 7 is located on one side of the main chamber 1 and communicates with the main chamber 1, and there is a first gate 6 between the main chamber 1 and the first auxiliary chamber 7; Two auxiliary chambers 7' are used to provide a vacuum protection or atmosphere buffer environment, and to take out crystals from the main chamber 1 under this environment, and the second auxiliary chamber 7' is located on the other side of the main chamber 1 , communicating with the main chamber 1, there is a second gate 6' between the main chamber 1 and the second auxiliary chamber 7'; and the first and second auxiliary chambers 7 pass through the first and second gates 6 , 6' are respectively isolated from the main chamber 1 (Fig. 3).

The main chamber 1 also includes a device support 0 ( FIG. 3 ), which is used to support the above-mentioned device components, or can also provide other auxiliary functions of the crystal growth device, such as the carrier gas used in the crystal growth process. (such as hydrogen), reaction source gas (such as silicon-containing, carbon-containing gas), P-type and N-type dopants, vacuum pump system, power supply system, etc. The functions of the setting stand include but are not limited to the above-mentioned content, and each module unit can also be rationally arranged and configured according to specific needs.

According to another embodiment of the crystal growth device provided by the present invention, the first and second auxiliary chambers 7, 7' include guide rails for carrying sample racks and rod-shaped components 9 for loading or taking samples along the guide rails. The rod-shaped part 9 is selected from a magnetic rod or a hook-shaped rod, and is used for loading, taking and placing the sample rack through magnetic attraction or hook hooking.

As shown in FIG. 3 , the first auxiliary chamber 7 and the second auxiliary chamber 7' are located on opposite sides of the main chamber 1, respectively. Those skilled in the art can clearly understand according to the teaching of the present invention that the first auxiliary chamber 7 and the second auxiliary chamber 7' can be located around the main chamber 1 at any angle. It can be arranged arbitrarily according to the design needs of the site and assembly line.

According to the crystal growth device provided by one embodiment of the present invention, its main chamber 1 also includes: a fixed tray 5 and a movable tray 4 (shown in dotted line); a movable insulating wall 10 for surrounding the crystal growth The inner wall of the main chamber 1 forms a sample growth chamber in the middle of the movable insulating wall 10 . In this embodiment, the inner walls of the main chamber 1 are all movable, which can be a whole movable thermal insulation wall, or multiple independent movable thermal insulation walls (Fig. 3).

In the crystal growth device provided according to one embodiment of the present invention, its main chamber 1 further includes: a fixed thermal insulation wall 2 and a movable thermal insulation wall 10, and the movable thermal insulation wall 10 is located on the path for sample transmission, and these fixed thermal insulation walls 2 and the movable insulating wall 10 surround the inner wall of the main chamber 1 where crystals grow, and a sample growth chamber is formed in the middle of the fixed insulating wall 2 and the movable insulating wall 10 . Specifically, the number of the movable thermal insulation walls is 2, including the first movable thermal insulation wall and the second movable thermal insulation wall, which are respectively located in the first auxiliary chamber 7 and the main chamber 1, so The junction of the main chamber 1 and the second auxiliary chamber 7'; when the crystal growth is completed, by lowering the first movable insulation wall and/or the second movable insulation wall 2, the second movable insulation wall A rod-shaped part 9 in one auxiliary chamber 7 and/or in a second auxiliary chamber 7' enables the transport and/or removal of the movable tray 4 from said main chamber 1 (Fig. 3).

As shown in Figure 4 or 5, in the crystal growth device provided by the present invention, the main chamber 1 further includes: a fixed tray 5 and a movable tray 4, which are respectively located in the crystal growth chamber inside the main chamber 1, And the fixed tray 5 is arranged on the movable tray 4, and the movable tray 4 can rotate and move up and down.

According to another embodiment of the crystal growth apparatus provided by the present invention, the main chamber further includes: an induction heating barrel 12 located inside the crystal growth chamber and an induction heating coil 13 located outside the crystal growth chamber. The crystal growth chamber also includes an insulating insulation jacket 20, which is arranged around the induction heating barrel 12 to ensure a stable and reliable temperature required for crystal growth, thereby obtaining silicon carbide crystals of high quality.

According to another embodiment of the crystal growth device provided by the present invention, the pipeline for delivering the source gas is composed of double-layer or multi-layer sleeves, wherein the gas delivered in the channel between the outer sleeve and the inner sleeve is used To restrict the gas flow direction of the inner sleeve. The gas delivered in the channel between the outer casing and the inner casing is used to limit the gas flow direction of the inner casing, which is beneficial to ensure the stability of the gas flow pressure during the crystal growth process and the uniformity of the grown SiC crystal wait. Those skilled in the art can clearly know according to the teaching of the present invention that according to the specific crystal growth process, the number of inner layer casings in the multilayer casing depends on the type of gas that needs to be input and various possible protective gases or inerts. gas etc.

Pneumatic sample holder passages 17 and 18 are used to drive the movable tray 4 to rotate and move up and down by the gas delivered through the passages. Wherein the pneumatic sample holder channel 17 is an air inlet channel, and 18 is an air outlet channel, and the air inlet channel 17 is set closer to the center of the sample holder relative to the air outlet channel 18 .

With reference to the foregoing exemplary description of the present invention, those skilled in the art can clearly understand that the present invention has the following advantages:

1. The CVD silicon carbide crystal growth device provided by the present invention can continue the production of the next crystal ingot without cooling down and shutting down the furnace by setting at least two auxiliary chambers (units) outside the main chamber. It overcomes the limitation that the crystal growth device in the prior art can only grow one crystal ingot in one furnace and cannot grow crystals continuously; it improves the efficiency of crystal growth and can meet the needs of large-scale development of the SiC industry.

2. In the CVD silicon carbide crystal growth device provided by the present invention, the thermal insulation wall connected to the auxiliary cavity in the main growth chamber is movable, and the inner wall is formed together with the fixed thermal insulation wall when growing crystal ingots to play the role of thermal insulation and maintaining the airflow field , ensuring the reliability of the crystal growth environment and the stability of the quality.

In addition, when the crystal growth is completed or interrupted, the movable insulation wall subsides to a certain height, so that the magnetic rod in the auxiliary chamber can send and pick up the movable tray located in the main growth chamber, so as to complete the continuous production without cooling down and shutting down the furnace .

In addition, it should be noted that relative terms in the present invention, such as "first", "second", "one side" and "another side" and similar expressions are only used to distinguish between one entity or action and another Distinguishing one entity or action from another does not necessarily require or imply any stated relationship or ordering of the aforementioned entities or actions. Finally, it should be noted that, in order to avoid obscuring the present invention by disclosing unnecessary details, the accompanying drawings of the present invention only show the structural and/or process steps closely related to the technical solution, and others related to the gist of the present invention Details not closely related to ideas have been omitted.

Although the present invention has been described based on some preferred embodiments, those skilled in the art should understand that the scope of the present invention is not limited to those embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art can carry out various changes and modifications to the embodiments on the basis of understanding the present invention, and therefore fall within the protection defined by the appended claims of the present invention. scope.

Claims (9)

1. A continuous HTCVD silicon carbide crystal growth device, comprising: A main chamber, which is a cylindrical hollow body, is used to provide a vacuum environment for crystal growth. The radial direction of the main chamber passes through a tail gas pipeline, and a source gas pipeline is opened below the tail gas pipeline; a movable tray, located in the main chamber, above the source gas pipeline, the movable tray can be driven by the gas to rotate and move up and down; a fixed tray, located in the main chamber, above the movable tray; A first auxiliary chamber is used to provide a vacuum buffer environment and provide samples to the main chamber under this environment. The first auxiliary chamber is located on one side of the main chamber and communicates with the main chamber. There is a first gate between the chamber and the first auxiliary chamber; A second auxiliary chamber is used to provide a vacuum buffer environment, and take out samples to the main chamber under this environment, the second auxiliary chamber is located on the other side of the main chamber, communicates with the main chamber, and There is a second gate between the main chamber and the second auxiliary chamber; Wherein the first and second auxiliary chambers are respectively isolated from the main chamber by first and second gates. 2 . The continuous HTCVD silicon carbide crystal growth device according to claim 1 , wherein the first and second auxiliary chambers include guide rails for carrying sample holders and rod-shaped parts for loading or taking out samples along the guide rails. 3. The continuous HTCVD silicon carbide crystal growth device according to claim 2, wherein the rod-shaped member is selected from a magnetic rod or a hook rod. 4 . The continuous HTCVD silicon carbide crystal growth device according to claim 1 , wherein the first auxiliary chamber and the second auxiliary chamber are respectively located on opposite sides of the main chamber. 5. The continuous HTCVD method silicon carbide crystal growth device according to claim 1, wherein said main chamber further comprises: a movable insulation wall, which is used to surround the inner wall of said crystal growth main chamber. The middle of the dynamic insulation wall forms the sample growth chamber. 6. The continuous HTCVD method silicon carbide crystal growth device according to claim 1, wherein said main chamber also comprises: a fixed thermal insulation wall and a movable thermal insulation wall, and the movable thermal insulation wall is positioned on the passage for sample transmission, and the fixed thermal insulation wall The thermal insulation wall and the movable thermal insulation wall surround the inner wall of the main crystal growth chamber, and a sample growth chamber is formed in the middle of the fixed thermal insulation wall and the movable thermal insulation wall. 7. The continuous HTCVD silicon carbide crystal growth device according to claim 6, wherein the number of the movable insulation walls is 2, which are respectively located in the first auxiliary chamber and the main chamber, the The junction of the main chamber and the second auxiliary chamber; when the crystal growth is completed, by lowering the movable insulation wall, the rod-shaped parts in the first auxiliary chamber and/or the second auxiliary chamber The movable tray can be transported and/or removed from the main chamber. 8. The continuous HTCVD method silicon carbide crystal growth device according to claim 1, wherein the sample growth chamber in the main chamber also includes an induction heating barrel and an induction heating coil positioned outside the induction heating barrel, an insulating insulation cover , the insulation insulation cover is located around the induction heating barrel. 9. The continuous HTCVD silicon carbide crystal growth device according to claim 1, wherein the pipeline for delivering the source gas is made of double-layer or multi-layer sleeves, wherein the outer sleeve and the inner sleeve The gas delivered by the channel is used to restrict the gas flow direction of the inner sleeve.

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