Apparatus and method for producing nitrogen-doped single crystal silicon

Abstract

The embodiments of the present disclosure disclose an apparatus and method for producing nitrogen-doped single crystal silicon, which may include a quartz crucible for containing a nitrogen-doped silicon melt, a first gas delivery device for delivering carbon monoxide gas to the surface of the nitrogen-doped silicon melt, and a crystal pulling device for pulling a single crystal silicon rod by a direct pulling method using the nitrogen-doped silicon melt.

Description

[Technical Field]

[0001] (CROSS-REFERENCE TO RELATED APPLICATIONS) This disclosure claims priority to a Chinese patent application filed in China on September 30, 2021, with application number 202111162445.6, the entire contents of which are incorporated herein by reference.

[0002] FIELD OF THE DISCLOSURE This disclosure relates to the field of semiconductor silicon wafer manufacturing, and more particularly to equipment and methods for manufacturing nitrogen-doped single crystal silicon. [Background technology]

[0003] Silicon wafers used in the production of semiconductor electronic components such as integrated circuits are primarily produced by slicing single-crystal silicon rods pulled by the direct pulling (Czochralski) method. The Czochralski method involves melting polycrystalline silicon in a quartz crucible to obtain a silicon melt, immersing a single-crystal seed in the silicon melt, and continuously lifting the seed away from the silicon melt surface, thereby growing a single-crystal silicon rod at the phase interface during the process.

[0004] During the manufacturing process, it is highly advantageous to provide a silicon wafer that includes a defect-free region (denuded zone (DZ)) extending from the front surface toward the body and a region with bulk microdefects (BMDs) adjacent to the DZ and extending further toward the body. The front surface refers to the surface of the silicon wafer where electronic components are to be formed. To form electronic components on a silicon wafer, the region where the electronic components are to be formed must be free of defects. Failure to do so would result in circuit breakage or other malfunctions. The DZ is important because it avoids the effects of defects. Furthermore, the BMDs act as intrinsic getters (IGs) for metal impurities, keeping them away from the DZ, thereby avoiding adverse effects such as increased leakage current and reduced gate oxide film quality.

[0005] Meanwhile, during the manufacturing process of the silicon wafer having the above-mentioned BMD region, it is very advantageous to dope the silicon wafer with nitrogen, for example, by promoting the formation of nitrogen-cored BMDs, the BMDs can reach a certain density, allowing them to effectively function as metal getter sources, and further, it can favorably affect the BMD density distribution, for example, making the BMD density distribution in the radial direction of the silicon wafer more uniform, for example, making the BMD density higher in the region close to the DZ and gradually decreasing toward the body of the silicon wafer.

[0006] To dope silicon wafers with nitrogen, nitrogen can be doped into the silicon melt in a quartz crucible, which results in nitrogen being doped into the extracted single crystal silicon rod and the silicon wafers obtained by cutting the single crystal silicon rod.

[0007] In the process of pulling nitrogen-doped single crystal silicon rods using a nitrogen-doped silicon melt, the nitrogen in the doped silicon melt volatilizes from the silicon melt in the form of nitrogen gas and cannot enter the silicon rods during the process of pulling the single crystal silicon rods, resulting in losses. This causes a decrease in the nitrogen concentration in the entire silicon rods, and the beneficial effects of the nitrogen doping cannot be effectively realized. Summary of the Invention

[0008] To solve the above technical problems, embodiments of the present disclosure preferably provide an apparatus and method for producing nitrogen-doped single crystalline silicon that can effectively avoid the loss of doping agent due to nitrogen volatilization.

[0009] The technical solution of the present disclosure is realized as follows:

[0010] In a first aspect, embodiments of the present disclosure provide an apparatus for producing nitrogen-doped single crystalline silicon, the apparatus comprising: a quartz crucible for containing the nitrogen-doped silicon melt; a first gas delivery device for delivering carbon monoxide gas to the surface of the nitrogen-doped silicon melt; and a crystal pulling device for pulling a single crystal silicon rod by a direct pulling method using the nitrogen-doped silicon melt.

[0011] In a second aspect, embodiments of the present disclosure provide a method for producing nitrogen-doped single crystalline silicon, the method comprising: Containing a nitrogen-doped silicon melt in a quartz crucible; delivering carbon monoxide gas to the surface of the nitrogen-doped silicon melt; and pulling a single crystal silicon rod using the nitrogen-doped silicon melt by a direct pulling method.

[0012] An embodiment of the present disclosure provides an apparatus and method for producing nitrogen-doped single crystal silicon. When a nitrogen-doped silicon melt is contained in a quartz crucible, the quartz crucible contains silicon dioxide (SiO2), and therefore, at high temperatures when the nitrogen-doped silicon melt is in a molten state, a first chemical reaction of Si+SiO2→2SiO occurs. The SiO generated here exists in gas form at high temperatures. When carbon monoxide gas is then transported to the liquid surface of the nitrogen-doped silicon melt, the carbon monoxide gas, the doping nitrogen volatilized in the form of nitrogen gas, and the SiO generated by the first chemical reaction undergo a second chemical reaction of 3SiO+2N2+3CO→Si3N4+3CO2. The generated Nitriding Silicon (Si3N4) has a high melting point and remains in a solid state even at high temperatures, so it returns to the melt, thereby reducing the nitrogen loss and the degree of decrease in nitrogen concentration throughout the extracted single crystal silicon rod. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a structural schematic diagram of an apparatus for producing nitrogen-doped single-crystalline silicon according to an embodiment of the present disclosure. [Figure 2] FIG. 1 is a schematic flow diagram of a method for producing nitrogen-doped single crystalline silicon according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0014] The technical solutions in the embodiments of the present disclosure will be clearly and completely described below with reference to the drawings in the embodiments of the present disclosure.

[0015] As shown in FIG. 1 , an embodiment of the present disclosure provides an apparatus 1 for producing nitrogen-doped single crystal silicon, which may include a quartz crucible 10, a first gas delivery device 20, and a crystal pulling device 30.

[0016] The quartz crucible 10 is used to contain the nitrogen-doped silicon melt M.

[0017] The first gas delivery device 20 is used to deliver carbon monoxide (CO) gas to the liquid surface L of the nitrogen-doped silicon melt M. Here, FIG. 1 schematically shows a specific implementation of the first gas delivery device 20 when a quartz crucible 10 and the nitrogen-doped silicon melt M contained in the quartz crucible 10 are inside a furnace body 2. As shown in FIG. 1, the first gas delivery device 20 delivers carbon monoxide gas into the furnace body 2 and to the liquid surface L of the nitrogen-doped silicon melt M, as schematically shown by solid arrows.

[0018] The crystal pulling apparatus 30 is used to pull up the single crystal silicon rod R by a direct pulling method using the nitrogen-doped silicon melt M. Here, the crystal pulling apparatus 30 shown schematically in Fig. 1 is located at the top of the furnace body 2, and moves the single crystal silicon rod R in the direction indicated by the hollow arrow in Fig. 1 so that the single crystal silicon rod R continuously grows at the phase interface or liquid surface L.

[0019] When the nitrogen-doped silicon melt M is contained in a quartz crucible 10, the component of the quartz crucible 10 is silicon dioxide (SiO2), so at high temperatures when the nitrogen-doped silicon melt M is in a molten state, a first chemical reaction of Si + SiO2 → 2SiO occurs. The silicon dioxide (SiO) produced here exists in gas form at high temperatures. When carbon monoxide gas is then transported to the liquid surface L of the nitrogen-doped silicon melt M, the carbon monoxide gas, the doping nitrogen volatilized in the form of nitrogen gas, and the SiO produced by the first chemical reaction undergo a second chemical reaction of 3SiO + 2N2 + 3CO → Si3N4 + 3CO2. Here, the produced CO2 exists in gas form at high temperatures, but the produced CO2 NitridingSilicon (Si3N4) has a high melting point and remains in a solid state even at high temperatures, so it returns to the melt, thereby reducing the nitrogen loss and the degree of decrease in nitrogen concentration throughout the extracted single crystal silicon rod.

[0020] Regarding obtaining the nitrogen-doped silicon melt M, the apparatus 1 according to the embodiment of the present disclosure may further include a heater 40, as shown in Fig. 1. The heater 40 is used to heat the quartz crucible 10 so as to melt the silicon nitride and polycrystalline silicon contained in the quartz crucible 10 to obtain the nitrogen-doped silicon melt M.

[0021] Regarding the implementation manner of the first gas transport device 20, in one example, as shown in FIG. 1, the first gas transport device 20 may include a first gas supplier 21 and a guide tube 22.

[0022] The first gas supplier 21 is used to supply carbon monoxide gas, specifically to supply it into the furnace body 2.

[0023] The guide tube 22 is used to guide the carbon monoxide gas supplied from the first gas supplier 21, specifically the carbon monoxide gas already supplied inside the furnace body 2, to the liquid surface L of the nitrogen-doped silicon melt M.

[0024] In order to avoid an undesirable chemical reaction between the high-temperature nitrogen-doped silicon melt M and a gas in the surrounding environment, such as oxygen in the atmosphere, it is necessary to maintain the nitrogen-doped silicon melt M in an atmosphere of a protective gas. To this end, as shown in FIG. 1, the equipment 1 may further include a second gas supplier 50. The second gas supplier 50 is used to supply an inert gas and to supply it into the furnace body 2, as schematically indicated by the dashed arrow in FIG. 1. Here, the guide tube 22 is further used to guide the inert gas supplied from the second gas supplier 50 to the liquid surface L of the nitrogen-doped silicon melt M, as schematically indicated by the dashed arrow in FIG. 1.

[0025] Regarding the type of the inert gas, in one example, the inert gas may be argon gas.

[0026] As shown in FIG. 2 , an embodiment of the present disclosure further provides a method for producing nitrogen-doped single crystalline silicon, the method comprising: Containing a nitrogen-doped silicon melt in a quartz crucible; delivering carbon monoxide gas to the surface of the nitrogen-doped silicon melt; and pulling a single crystal silicon rod by a direct pulling method using the nitrogen-doped silicon melt.

[0027] Regarding the method for obtaining the nitrogen-doped silicon melt according to the embodiment of the present disclosure, the method further comprises: The method may include heating the quartz crucible to melt silicon nitride and polycrystalline silicon contained in the quartz crucible to obtain the nitrogen-doped silicon melt.

[0028] In one example, delivering the carbon monoxide gas to the surface of the nitrogen-doped silicon melt comprises: providing carbon monoxide gas; and directing the supplied carbon monoxide gas to the liquid surface of the nitrogen-doped silicon melt.

[0029] As mentioned above, to maintain the nitrogen-doped silicon melt in an atmosphere of protective gas, the method further comprises: supplying an inert gas; and directing the supplied inert gas together with the carbon monoxide gas to the liquid surface of the nitrogen-doped silicon melt.

[0030] The inert gas in the above method may be argon gas.

[0031] In addition, if there is no conflict between the technical solutions described in the embodiments of the present disclosure, they may be arbitrarily combined.

[0032] The above are only specific embodiments of the present disclosure, but the scope of protection of the present disclosure is not limited thereto, and within the technical scope disclosed in the present disclosure, those skilled in the art can easily think of modifications and substitutions, all of which should be included in the scope of protection of the present disclosure. Therefore, the scope of protection of the present disclosure should be governed by the claims.

Claims

1. 1. A method for producing nitrogen-doped single crystalline silicon, comprising: The method comprises: Containing a nitrogen-doped silicon melt in a quartz crucible; delivering carbon monoxide gas to the surface of the nitrogen-doped silicon melt; Pulling a single crystal silicon rod by a direct pulling method using the nitrogen-doped silicon melt; The carbon monoxide gas, the nitrogen gas generated by volatilization of nitrogen in the doped silicon melt, and gaseous SiO react to form silicon nitride (Si ３ N ４ ) and The gaseous SiO is produced by the reaction of silicon dioxide contained in the quartz crucible with the nitrogen-doped silicon melt in a molten state. A method for producing nitrogen-doped single crystal silicon.

2. The method further comprises: and heating the quartz crucible to melt the silicon nitride and polycrystalline silicon contained in the quartz crucible to obtain the nitrogen-doped silicon melt. The method of claim 1.

3. The step of delivering the carbon monoxide gas to the surface of the nitrogen-doped silicon melt comprises: providing carbon monoxide gas; and directing the supplied carbon monoxide gas to the liquid surface of the nitrogen-doped silicon melt.

3. The method according to claim 1 or 2.

4. The method further comprises: supplying an inert gas; and introducing the supplied inert gas together with the carbon monoxide gas to the liquid surface of the nitrogen-doped silicon melt. The method of claim 3.

5. The inert gas is argon gas. The method of claim 4.

6. 1. An apparatus for producing nitrogen-doped single crystal silicon, comprising: The apparatus employs the method for producing nitrogen-doped single crystal silicon according to claim 1, The device comprises: a quartz crucible for containing the nitrogen-doped silicon melt; a first gas delivery device for delivering carbon monoxide gas to the surface of the nitrogen-doped silicon melt; and a crystal pulling device for pulling a single crystal silicon rod by a direct pulling method using the nitrogen-doped silicon melt. Equipment for producing nitrogen-doped single-crystal silicon.

7. the device further comprising a heater; The heater is used to heat the quartz crucible so as to melt the silicon nitride and polycrystalline silicon contained in the quartz crucible to obtain the nitrogen-doped silicon melt.

7. The device of claim 6.

8. The first gas transport device is a first gas supplier for supplying carbon monoxide gas; a guide tube for guiding the carbon monoxide gas supplied from the first gas supplier to the liquid surface of the nitrogen-doped silicon melt.

8. The device according to claim 6 or 7.

9. The device further comprises: a second gas supplier for supplying an inert gas; The guide tube is further used to guide the inert gas supplied from the second gas supplier to the surface of the nitrogen-doped silicon melt.

9. The device of claim 8.

10. The inert gas is argon gas.

10. The device of claim 9.

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