Silicon precursor composition, high-density doped silicon nitride film, and preparation method and application of high-density doped silicon nitride film
By using phosphorus-containing compounds as silicon precursor compositions, doped silicon nitride thin films were prepared at low temperatures using atomic layer deposition, solving the problems of high thermal budget and low density in the high-temperature preparation of silicon nitride thin films in the prior art. This achieved the preparation of high-quality silicon nitride thin films and improved the performance of semiconductor devices.
Patent Information
- Application Number
- CN202511716095.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-21
- Publication Date
- 2026-02-27
AI Technical Summary
Existing ALD technology for preparing silicon nitride thin films requires high temperatures, resulting in high thermal budgets, low film density, and poor quality. Furthermore, plasma-enhanced ALD produces films with lower density and higher porosity.
Using phosphorus-containing compounds as silicon precursor compositions, doped silicon nitride thin films are prepared at relatively low temperatures via atomic layer deposition. The highly active amino and phosphine groups are utilized to promote metal deposition and phosphine doping, resulting in high-density, low-impurity silicon nitride thin films.
High-density, low-impurity silicon nitride thin films were prepared at lower temperatures, improving the quality and performance of the films and enhancing the performance of semiconductor devices.
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Abstract
Description
Technical Field
[0001] This invention belongs to the field of semiconductor technology, specifically relating to a silicon precursor composition, a high-density doped silicon nitride thin film, its preparation method and application. Background Technology
[0002] Silicon-based thin films, especially silicon nitride ( ) and silicon dioxide ( Thin films are indispensable key functional materials in modern semiconductor devices, and are widely used in gate sidewalls, etch stop layers, device passivation layers, capacitor dielectric layers, and interlayer dielectrics.
[0003] Atomic layer deposition (ALD) is a commonly used process for preparing silicon nitride thin films. Its principle is based on sequentially introducing chemical reactants into a reaction chamber containing a substrate, and achieving deposition through controlled surface reactions. Because surface reactions typically have self-limiting properties, ALD technology allows for precise control of film thickness and achieves excellent conformal substrate coverage. However, several limitations are known in ALD methods for depositing silicon nitride thin films. For example, thermal ALD typically requires high temperatures (approximately 600°C to 800°C) to promote various surface reactions, but these high temperatures result in extremely high thermal costs and poor compatibility with other processes. While plasma-enhanced ALD can be performed at lower temperatures, silicon nitride films prepared by this method often exhibit low density and high porosity, leading to poor film quality. Summary of the Invention
[0004] Therefore, the technical problem to be solved by the present invention is to provide a silicon precursor composition for preparing doped silicon nitride thin films, which can increase the density of silicon nitride thin films, reduce the residual impurities in the films, and improve the quality of silicon nitride thin films.
[0005] To address the aforementioned technical problems, the present invention provides the following technical solution: In a first aspect, this application provides a silicon precursor composition for preparing silicon nitride thin films, wherein the silicon precursor composition comprises a phosphorus-containing compound with the structure shown in Chemical Formula I and / or Chemical Formula II.
[0006] Formula I Formula II R1', R2', R3', R4', R5' and R6' are each independently selected from diphenylphosphine, diethylphosphine, dimethylphosphine, phenylphosphine, dicyclopentylphosphine, di(2-furanyl)phosphine, (diphenylphosphinemethyl)diphenylphosphine or (diphenylphosphineethyl)diphenylphosphine.
[0007] In some embodiments of this application, the phosphorus-containing compound is selected from one or more of bis(diphenylphosphine)aminosilane, bis(diethylphosphine)aminosilane, bis(dimethylphosphine)aminosilane, bis(di(dimethylphosphine)amino)silane, bis(di(dicyclopentylphosphine)amino)silane, bis(di(diethylphosphine)amino)silane, or bis(di(diphenylphosphine)amino)silane; Preferably, the phosphorus-containing compound is selected from one or more of the following groups of compounds:
[0008] Compound a, Compound b, Compound c, Compound d.
[0009] Secondly, this application provides a method for preparing a doped silicon nitride thin film, which includes the following steps: (1) Provide a substrate in the reaction chamber; (2) The silicon precursor composition of claim 1 or 2 is introduced into the reaction chamber by atomic layer deposition, so that it is chemically adsorbed onto the substrate surface to form a first reaction product on the substrate surface; (3) Metal inorganic salts are introduced into the reaction chamber by atomic layer deposition, so that they are chemically adsorbed with the first reaction product to obtain the second reaction product; (4) Introduce nitrogen source plasma gas into the reaction chamber to react with the second reaction product to obtain a doped silicon nitride thin film.
[0010] In some embodiments of this application, the preparation method includes repeating steps (2) to (4) at least twice; preferably repeating steps (2) to (4) 2-100 times.
[0011] In some embodiments of this application, in step (2), the silicon precursor composition is introduced into the reaction chamber in a pulsed manner using a carrier gas; Preferably, the carrier gas is selected from one or more of nitrogen, argon, helium or krypton, and the preferred flow rate of the carrier gas is 100-500 sccm. More preferably, the temperature of the reaction chamber in step (2) is 250-450°C, and the pressure of the reaction chamber is preferably 150-550 Pa; More preferably, the time for the silicon precursor composition to chemically adsorb onto the substrate is 2-10 seconds.
[0012] In some embodiments of this application, the inorganic metal salt in step (3) includes one or more of aluminum chloride, gallium chloride, indium chloride, copper chloride, or thallium chloride, preferably copper chloride.
[0013] In some embodiments of this application, in step (3), the metal inorganic salt is introduced into the reaction chamber in a pulsed manner using a carrier gas; Preferably, the carrier gas is selected from one or more of nitrogen, argon, helium or krypton, and the preferred flow rate of the carrier gas is 100-500 sccm. More preferably, the temperature of the reaction chamber in step (3) is 250-450°C, and the pressure of the reaction chamber is preferably 150-550 Pa; More preferably, the reaction time between the metal salt compound and the first reaction product is 2-10 seconds.
[0014] In some embodiments of this application, in step (4), the nitrogen source plasma gas is selected from nitrogen plasma gas and / or ammonia plasma gas; Preferably, the flow rate of the nitrogen source plasma gas is 100-500 sccm; More preferably, the reaction time between the nitrogen source plasma gas and the second reaction product is 10-60 s; More preferably, the temperature of the reaction in step (4) is 250-450°C, and the preferred reaction pressure is 150-550 Pa.
[0015] Thirdly, this application also provides a doped silicon nitride thin film, wherein the doped silicon carbide thin film is prepared by the above-described preparation method; preferably, the density of the doped silicon carbide thin film is 6.0-6.5 g / cm³. 3 ; Preferably, in the doped silicon carbide film, the sum of the contents of silicon, nitrogen, carbon, phosphorus and doped metal elements in the doped silicon nitride film is greater than or equal to 99 wt% relative to all elements except hydrogen and helium.
[0016] Fourthly, this application also provides the application of the above-mentioned doped silicon nitride thin film in the semiconductor industry and / or microelectronics field.
[0017] Beneficial effects: The silicon precursor composition of this invention contains amino and phosphine groups. The phosphorus atom in the phosphine group possesses a lone pair of electrons, making it a very strong σ-electron donor. This means it can form strong and stable coordination bonds with most metal precursors, allowing for better metal deposition on the film surface via chemisorption when used to prepare silicon nitride thin films. Both amino and phosphine groups are highly reactive groups, acting as catalytic sites to greatly promote the chemical reaction and decomposition of precursor molecules on the substrate surface. This high reactivity reduces dependence on thermal energy, making it possible to complete cleavage and bonding at lower temperatures. Furthermore, phosphine doping can replace nitrogen atoms in the network (forming PN bonds), shortening the average bond length and allowing for more efficient accommodation of metal atoms, thus optimizing atomic packing. Therefore, when used to prepare silicon nitride thin films, it increases the film density and improves the film purity. Further, by introducing metal salt compounds to dope the metal in the film, high-quality, highly conformal SiN thin films can be obtained at lower deposition temperatures, resulting in superior semiconductor device performance. Detailed Implementation
[0018] The present invention will now be described in detail with reference to embodiments. The principles and features of the present invention are described below with reference to embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other. The embodiments given are only for explaining the present invention and are not intended to limit the scope of the present invention.
[0019] In this application, the term "atomic layer deposition," abbreviated as "ALD," refers to a vapor deposition process in which deposition cycles, such as multiple consecutive deposition cycles, are performed in a reaction space (i.e., one or more reaction chambers). Typically, in an ALD process, during each deposition cycle, a precursor is introduced into the reaction space and adsorbed onto the surface of a substrate (substrate). The substrate surface may include previously deposited material from previous ALD cycles or other materials, forming at most one precursor monolayer that is not readily reacted with additional excess precursor (i.e., a self-limiting reaction). Subsequently, in some cases, another precursor or reactant may be introduced into the reaction space to convert the previously chemisorbed precursor into the desired material on the substrate surface. Other reaction steps may be included in the deposition cycle. ALD can occur via a thermal process (thermal ALD), where the reaction is promoted by increasing the substrate temperature relative to ambient temperature; and / or via a plasma-enhanced ALD process, where the reaction is promoted by using high-energy plasma materials.
[0020] In a first aspect, in one specific embodiment of this application, this application provides a silicon precursor composition for preparing silicon nitride thin films, comprising phosphorus-containing compounds with structures as shown in Chemical Formula I and / or Chemical Formula II.
[0021] Formula I Formula II R1', R2', R3', R4', R5' and R6' are each independently selected from diphenylphosphino (Ph2P), diethylphosphino (Et2P), dimethylphosphino (Me2P), phenylphosphino (PhP), dicyclopentylphosphino (Cy2P), di(2-furanyl)phosphino ((2-Furyl)2P), (diphenylphosphinomethyl)diphenylphosphino (Ph2P(CH2)PPh) or (diphenylphosphinoethyl)diphenylphosphino (PhP(CHCH2)PPh).
[0022] In some specific embodiments of this application, the phosphorus-containing compound is selected from one or more of bis(diphenylphosphine)aminosilane, bis(diethylphosphine)aminosilane, bis(dimethylphosphine)aminosilane, bis(di(dimethylphosphine)amino)silane, bis(di(dicyclopentylphosphine)amino)silane, bis(di(diethylphosphine)amino)silane, or bis(di(diphenylphosphine)amino)silane.
[0023] In some specific embodiments of this application, the phosphorus-containing compound is selected from one or more of the following groups of compounds:
[0024] Compound a, Compound b, Compound c, Compound d.
[0025] Secondly, this application provides a method for preparing the above-mentioned phosphorus-containing compound, which is obtained by a substitution reaction of aminosilane and chlorophosphine-based organic compound.
[0026] The lone pair of electrons in organoaminosilanes can act as nucleophiles, attacking the P-Cl bond in chlorophosphine-based organic compounds, causing substitution, generating a PN bond, and thus forming phosphine-based aminosilanes.
[0027] Specifically, the preparation method of the phosphorus-containing compound includes the following steps: (1) Add aminosilane and triethylamine to the first solvent and cool to -75 to -85°C; (2) Add a mixture of chlorophosphine-based organic compound and first solvent to the mixture in step (1) and react at -75 to -85°C to obtain the phosphorus-containing compound.
[0028] In some embodiments of this application, the reaction time in step (2) is 30-90 min.
[0029] In some embodiments of this application, the aminosilane is selected from compounds represented by Formula III and / or Formula IV.
[0030] Formula III Formula IV Among them, R1, R2, R3, R4, R5, and R6 are each independently selected from C2-C 10 alkyl.
[0031] In some embodiments of this application, the aminosilane is selected from one or more of diisopropylaminosilane, dimethylaminosilane, di-n-propylaminosilane, di-n-butylaminosilane, di-tert-butylaminosilane, di(dimethylamino)silane, di(di-n-propylamino)silane, di(diisopropylamino)silane, di(di-n-butylamino)silane, and di(di-tert-butylamino)silane.
[0032] In some embodiments of this application, the chlorophosphoric organic compound is selected from one or more of the following: diphenylphosphine chlorophosphate (Ph2P-Cl), diethylphosphine chlorophosphate (Et2P-Cl), dimethylphosphine chlorophosphate (Me2PCl), phenylphosphine chlorophosphate (PhPCl2), dicyclopentylphosphine chlorophosphate (Cy2PCl), di(2-furanyl)phosphine chlorophosphate ((2-Furyl)2PCl), diphenylphosphine chlorophosphate (Ph2P(CH2)PPhCl), or diphenylphosphine chlorophosphate (PhP(CHCH2)PPhCl).
[0033] In some embodiments of this application, the first solvent in steps (1) and (2) is n-hexane.
[0034] In some embodiments of this application, the preparation method further includes a step of separating the phosphorus-containing compound. In some embodiments, the separation includes filtration and / or evaporation.
[0035] Thirdly, this application provides a method for preparing a doped silicon nitride thin film, comprising: (1) Provide a substrate in the reaction chamber; (2) A silicon precursor composition is introduced into the reaction chamber by atomic layer deposition, so that it is chemically adsorbed onto the substrate surface to form a first reaction product on the substrate surface; (3) Metal inorganic salts are introduced into the reaction chamber by atomic layer deposition, so that they are chemically adsorbed with the first reaction product to obtain the second reaction product; (4) Introduce nitrogen source plasma gas into the reaction chamber to react with the second reaction product to obtain a doped silicon nitride thin film; Wherein, the silicon precursor composition in step (2) comprises a phosphorus-containing compound with the structure shown in Formula I and / or Formula II,
[0036] Formula I Formula II R1', R2', R3', R4', R5' and R6' are each independently selected from diphenylphosphino (Ph2P), diethylphosphino (Et2P), dimethylphosphino (Me2P), phenylphosphino (PhP), dicyclopentylphosphino (Cy2P), di(2-furanyl)phosphino ((2-Furyl)2P), (diphenylphosphinomethyl)diphenylphosphino (Ph2P(CH2)PPh) or (diphenylphosphinoethyl)diphenylphosphino (PhP(CHCH2)PPh).
[0037] In some embodiments of this application, the above preparation method includes repeating steps (2) to (4) at least twice; preferably repeating steps (2) to (4) 2-100 times. It should be noted that in the above repeated cyclic operation, after the first cycle, in subsequent repeated operations, the silicon precursor composition described in step (1) undergoes chemical adsorption with the doped silicon nitride thin film layer obtained in the previous cycle step (4) to form a first reaction product. By controlling the number of cycles, a silicon nitride thin film of a predetermined thickness is obtained.
[0038] In some embodiments of this application, the substrate is a type of material commonly used in the semiconductor industry and microelectronics field. Those skilled in the art can make adaptive choices from the prior art according to actual needs. This invention is not particularly limited, and specific examples include, but are not limited to, one or more of silicon wafers, quartz, glass, and resin.
[0039] In some embodiments of this application, step (2) of introducing the silicon precursor composition into the reaction chamber by atomic layer deposition for chemical adsorption specifically includes: using a gas carrier to introduce the silicon precursor composition into the reaction chamber in a pulsed manner, wherein the precursor contacts the substrate surface for chemical adsorption to obtain the first reaction product. Further, the pulse period is as follows: the silicon precursor composition is introduced into the reaction chamber using a carrier gas for 5-10 seconds, followed by purging with a carrier gas for 30-40 seconds.
[0040] In this application, specific examples of atomic layer deposition in steps (2) and (3) include, but are not limited to, one or more of the following: hot cathode evaporation, molecular beam evaporation, ion beam deposition, organometallic decomposition evaporation and atomic layer chemical vapor deposition; more specifically, the processes and conditions for forming the first reactant or the second reactant by atomic layer deposition in steps (2) and (3) can be exactly the same, partially the same or completely different.
[0041] In some embodiments of this application, the carrier gas specifically includes, but is not limited to, one or more of nitrogen, argon, helium, or krypton.
[0042] In some implementations, the flow rate of the carrier in step (2) is 100-500 sccm.
[0043] In some embodiments, the silicon precursor composition undergoes chemisorption with the substrate surface for 2-10 seconds. It is understood that the substrate surface in this application may be the surface of a substrate material, or it may include the surface of a material layer obtained from a previous atomic layer deposition.
[0044] In some embodiments, during step (2), when the silicon precursor composition is chemically adsorbed onto the substrate, the temperature of the reaction chamber is 250-450°C, and the pressure of the reaction chamber is preferably 150-550 Pa.
[0045] In some embodiments of this application, the inorganic metal salt in step (3) includes one or more of aluminum chloride, gallium chloride, indium chloride, copper chloride, or thallium chloride, preferably copper chloride.
[0046] In some embodiments of this application, introducing a metal inorganic salt into the reaction chamber using atomic layer deposition (ALD) for chemisorption with the first reaction product includes: introducing the metal salt compound into the reaction chamber in a pulsed manner using a gas carrier; the metal salt compound then contacts the first reaction product for chemisorption to obtain a second reaction product. Further, the pulse period is as follows: the metal salt compound is introduced into the reaction chamber using a carrier gas for 5-10 seconds, followed by purging with a carrier gas for 30-40 seconds.
[0047] In some embodiments, the carrier gas specifically includes, but is not limited to, one or more of nitrogen, argon, helium, or krypton.
[0048] In some embodiments, the flow rate of the carrier in step (3) is 100-500 sccm.
[0049] In some embodiments, in step (3), when the metal salt compound undergoes chemical adsorption with the first reaction product, the temperature of the reaction chamber is 250-450°C, and preferably the pressure of the reaction chamber is 150-550 Pa.
[0050] In some embodiments, the metal salt compound reacts with the first reaction product for 2-10 seconds.
[0051] In some embodiments of this application, in step (4), the nitrogen source plasma refers to a reactive nitrogen-containing gas generated in situ or remotely by a plasma generator, and specific examples include, but are not limited to, nitrogen plasma gas and / or ammonia plasma.
[0052] In some embodiments of this application, the flow rate of the nitrogen source plasma gas is 100-500 sccm.
[0053] In some embodiments of this application, the reaction time between the nitrogen source plasma gas and the second reaction product is 10-60 s, preferably 20-30 s.
[0054] In some embodiments of this application, the temperature of the reaction in step (4) is 250-450°C, and the reaction pressure is preferably 150-550 Pa.
[0055] On the other hand, this application provides a doped silicon nitride thin film, which is prepared by the above-described preparation method.
[0056] In some embodiments of this application, the reaction time between the nitrogen source plasma gas and the second reaction product is 10-60 s, preferably 20-30 s.
[0057] In some embodiments of this application, the temperature of the reaction in step (4) is 250-450°C, and the reaction pressure is preferably 150-550 Pa.
[0058] On the other hand, this application provides a doped silicon nitride thin film, which is prepared by the above-described preparation method.
[0059] A further preferred value is 99.5-99.9 wt%. It is understood that the doped metal is the metal corresponding to the metal salt compound used in the preparation method.
[0060] On the other hand, this application also provides the application of the above-mentioned doped silicon nitride thin film in the semiconductor industry and / or microelectronics field.
[0061] The beneficial effects of the doped silicon carbide thin film and its preparation method described in this application will be illustrated below through specific embodiments.
[0062] All raw materials and reagents used in this invention were purchased from mainstream manufacturers on the market. Those without specified manufacturers or concentrations are all analytical grade raw materials or reagents that are routinely available. There are no particular restrictions as long as they achieve the intended effect. The instruments and equipment used in this embodiment were all purchased from major manufacturers on the market. There are no particular limitations as long as they achieve the intended effect. Where specific techniques or conditions are not specified in this embodiment, they shall be performed in accordance with the techniques or conditions described in the literature in this field or according to the product instructions.
[0063] The reagents and instruments used in the embodiments and comparative examples of this application are shown in Table 1. Table 1. Reagents and instruments used in the embodiments and comparative examples of this application. Example 1
[0064] Weigh 3.02 g (10 mmol) of DIPAS and 2.23 g (22 mmol) of Et3N in a glove box and transfer them to a three-necked flask. Add 25 mL of anhydrous n-hexane to the three-necked flask and cool to −78 °C. Dissolve 1.93 g (20 mmol) of Me2P-Cl (dimethylphosphorus chloride) in 15 mL of n-hexane, and then slowly inject it into the three-necked flask over 30 min at −78 °C (the solution changes from colorless to pale yellow, and a small amount of white fumes of Et3N·HCl appear). Stirring continued at −78°C for 1 h; the temperature was naturally raised to −40°C, and stirring was continued for 2 h. The product was filtered through a Celite pad at low temperature to remove the white precipitate of Et3N·HCl. The filter cake was washed with 2×5 mL of cold n-hexane, and the filtrates were combined. The solvent was evaporated at −40°C with an oil pump at 0.1 mbar. 4.88 g of product compound a ((di(dimethylphosphine)aminosilane)) was obtained. The NMR detection results are as follows: 1H-NMR (300 MHz, CDCl3) δ (ppm) 4.1 (s, 3H), 0.98 (s, 12H).
[0065] Example 2 Weigh 0.89 g (10 mmol) of Me2NSiH3 (dimethylaminosilane) and 2.23 g (22 mmol) of Et3N in a glove box and transfer them to a three-necked flask. Add 25 mL of anhydrous n-hexane to the flask and cool to −78 °C. Dissolve 4.41 g (20 mmol) of Ph2P-Cl (diphenylphosphine chloride) in 15 mL of n-hexane and slowly inject it into the three-necked flask over 30 min at −78 °C (the solution changes from colorless to pale yellow, and a small amount of white fumes of Et3N·HCl appear). Continue stirring at −78 °C for 1 h; allow to rise naturally to −40 °C and stir for another 2 h. Filter the solution at low temperature using a Celite sieve to remove the white precipitate of Et3N·HCl; wash the filter cake with 2 × 5 mL of cold n-hexane and combine the filtrates. The solvent was evaporated at -40℃ using an oil pump at 0.1 mbar; 4.72 g of product compound b ((di(diphenylphosphine)aminosilane)) was obtained. The NMR results are as follows: 1H-NMR (300 MHz, CDCl3) 4.1 (s, 3H), 7.15 (m, 8H), 7.42 (m, 12H). Example 3
[0066] Weigh 1.32 g (10 mmol) of (Me₂N)₂SiH₂ (bis(dimethylamino)silane) and 2.23 g (22 mmol) of Et₃N in a glove box and transfer them to a three-necked flask. Add 25 mL of anhydrous n-hexane to the flask and cool to −78 °C. Dissolve 2.49 g (20 mmol) of Et₂P-Cl (dimethylphosphorus chloride) in 15 mL of n-hexane, and then slowly inject it into the three-necked flask over 30 min at −78 °C (the solution changes from colorless to pale yellow, and a small amount of white fumes of Et₃N·HCl appear). Continue stirring at −78 °C for 1 h; allow to rise naturally to −40 °C, and stir for another 2 h. Filter the solution at low temperature using a Celite liner to remove the white precipitate of Et₃N·HCl; wash the filter cake with 2 × 5 mL of cold n-hexane and combine the filtrates. The solvent was evaporated at −40°C using an oil pump at 0.1 mbar to obtain 3.35 g of product compound c (bis(di(diethylphosphine)amino)silane). The NMR results are as follows: 1H-NMR (300 MHz, CDCl3) 4.8 (2H, s), 1.48 (16H, m), 0.96 (24H, t).
[0067] Example 4 Weigh 4.01 g (10 mmol) of (nBu2N)2SiH2 and 2.23 g (22 mmol) of Et3N in a glove box and transfer them to a three-necked flask. Add 40 mL of anhydrous n-hexane to the flask and cool to −78°C. Dissolve 4.82 g (20 mmol) of Cy2P-Cl (chlorodicyclopentylphosphide) in 20 mL of n-hexane, and then slowly inject it into the three-necked flask over 45 min at −78°C (the solution changes from colorless to pale yellow, and a small amount of white fumes of Et3N·HCl appear). Continue stirring at −78°C for 1 h; allow to rise naturally to −40°C and stir for another 3 h. Filter the solution at low temperature using a Celite liner to remove the white precipitate of Et3N·HCl; wash the filter cake with 2 × 10 mL of cold n-hexane and combine the filtrates. The solvent was evaporated at -40 °C using an oil pump at 0.1 mbar, yielding 7.51 g of the product compound d (bis(di(dicyclopentylphosphine)amino)silane). The NMR results are as follows: 1H-NMR (300 MHz, CDCl3) 3.4 (2H, s), 1.5 (4H, m), 1.635 (8H, m), 1.4 (8H, m), 1.73 (8H, m), 1.63 (8H, m).
[0068] Example 5 Preparation of doped silicon nitride thin films (1) Place the silicon wafer as a substrate into the reaction chamber, and set the reaction chamber temperature to 350℃ and the pressure to 150Pa; (2) Compound a was placed in a stainless steel source bottle, which was connected to the reaction chamber of the atomic layer deposition equipment via a pipeline. The source bottle was heated to 50°C, and nitrogen carrier gas was introduced at a flow rate of 200 sccm. Compound a was introduced into the reaction chamber in a pulsed manner for 6 s to allow compound a to chemically adsorb onto the substrate. Subsequently, nitrogen gas was introduced into the reaction chamber for 30 s to purge it, and the first reaction product was obtained on the substrate. (3) Copper chloride was placed in a stainless steel source bottle, which was connected to the reaction chamber of the atomic layer deposition equipment via a pipeline. The source bottle was heated to 50°C. Nitrogen carrier gas was introduced at a flow rate of 200 sccm. Copper chloride was introduced into the reaction chamber in a pulsed manner for 6 seconds to allow the copper chloride to chemically adsorb with the first reaction product. Then, nitrogen gas was introduced into the reaction chamber for 30 seconds to purge and obtain the second reaction product. (4) Nitrogen plasma gas is introduced into the reaction chamber at a flow rate of 200 sccm for 30 s to obtain a doped silicon nitride thin film. Repeat steps (2)-(4) 200 times to obtain a copper, carbon and phosphorus co-doped silicon nitride film with a thickness of 188 Å on the substrate. After the first cycle, the substrate in step (2) is the doped silicon nitride film obtained in step (4) of the previous cycle.
[0069] Example 6 Preparation of doped silicon nitride thin films (1) Place the silicon wafer as a substrate into the reaction chamber, and set the reaction chamber temperature to 250°C and the pressure to 550Pa; (2) Compound b was placed in a stainless steel source bottle, which was connected to the reaction chamber of the atomic layer deposition equipment via a pipeline. The source bottle was heated to 50°C, and nitrogen carrier gas was introduced at a flow rate of 200 sccm. Compound b was introduced into the reaction chamber in a pulsed manner for 2 seconds to allow it to chemically adsorb onto the substrate. Subsequently, nitrogen gas was introduced into the reaction chamber for 20 seconds to purge it, and the first reaction product was obtained on the substrate. (3) Gallium chloride is placed in a stainless steel source bottle. The source bottle is connected to the reaction chamber of the atomic layer deposition equipment through a pipeline. The heating temperature of the source bottle is 50°C. Nitrogen carrier gas is introduced with a flow rate of 300 sccm. Copper chloride is introduced into the reaction chamber in a pulsed manner for 2 seconds to allow gallium chloride to chemically adsorb with the first reaction product. Then, nitrogen gas is introduced into the reaction chamber for 20 seconds to purge and obtain the second reaction product. (4) Nitrogen plasma gas is introduced into the reaction chamber at a flow rate of 100 sccm and a duration of 60 s to purge and obtain a doped silicon nitride film. Repeat steps (2)-(4) 200 times to obtain a gallium, carbon and phosphorus co-doped silicon nitride film with a thickness of 192 Å on the substrate. After the first cycle, the substrate in step (2) is the doped silicon nitride film obtained in step (4) of the previous cycle.
[0070] Example 7 Preparation of doped silicon nitride thin films (1) Place the silicon wafer as a substrate into the reaction chamber, and set the reaction chamber temperature to 450℃ and the pressure to 350Pa; (2) Compound c was placed in a stainless steel source bottle, which was connected to the reaction chamber of the atomic layer deposition equipment via a pipeline. The source bottle was heated to 50°C, and nitrogen carrier gas was introduced at a flow rate of 100 sccm. Compound c was introduced into the reaction chamber in a pulsed manner for 10 s to allow it to chemically adsorb onto the substrate. Subsequently, nitrogen gas was introduced into the reaction chamber for 50 s to purge it, and the first reaction product was obtained on the substrate. (3) Indium chloride is placed in a stainless steel source bottle, which is connected to the reaction chamber of the atomic layer deposition equipment via a pipeline. The source bottle is heated to 50°C, and nitrogen carrier gas is introduced at a flow rate of 100 sccm. Indium chloride is introduced into the reaction chamber in a pulsed manner for 10 s to allow indium chloride to undergo a chemical adsorption reaction with the first reaction product. Then, nitrogen gas is introduced into the reaction chamber for 50 s to purge, and the second reaction product is obtained. (4) Nitrogen plasma gas is introduced into the reaction chamber at a flow rate of 300 sccm for 20 s to purge and obtain a doped silicon nitride film. Repeat steps (2)-(4) 200 times to obtain an indium, carbon and phosphorus co-doped silicon nitride film with a thickness of 194 Å on the substrate. After the first cycle, the substrate in step (2) is the doped silicon nitride film obtained in step (4) of the previous cycle.
[0071] Example 8 The difference from Example 5 is that the reaction temperature in step (1) is 450°C, while the rest is the same as in Example 5. A copper and phosphorus co-doped silicon nitride film with a thickness of 194 Å is prepared on the substrate.
[0072] Example 9 The difference between Example 9 and Example 5 is that the silicon precursor composition in step (2) is different. Example 9 uses compound d as the silicon precursor composition. The rest is the same as in Example 5, and a copper, carbon and phosphorus co-doped silicon nitride thin film with a thickness of 193 Å is prepared on the substrate.
[0073] Example 10 The difference from Example 5 is that the inorganic metal salt in step (3) is aluminum chloride, while the rest is the same as in Example 5. A silicon nitride film with a thickness of 195 Å co-doped with aluminum, carbon and phosphorus is prepared on the substrate.
[0074] Example 11 The difference from Example 5 is that the nitrogen purging time in steps (2)-(4) is 40s, while the rest is the same as in Example 5. A copper, carbon and phosphorus co-doped silicon nitride film with a thickness of 194Å is prepared on the substrate.
[0075] Example 12 The difference from Example 5 is that the metal salt compound in step (3) is zinc chloride, while the rest is the same as in Example 5. A zinc, carbon and phosphorus co-doped silicon nitride film with a thickness of 196 Å was prepared on the substrate.
[0076] Comparative Example 1 The difference between Comparative Example 1 and Example 5 is that Comparative Example 1 did not adsorb copper chloride onto the first reaction product, specifically including: (1) Place the silicon wafer as a substrate into the reaction chamber, and set the reaction chamber temperature to 350℃ and the pressure to 150Pa; (2) Compound a was placed in a stainless steel source bottle, which was connected to the reaction chamber of the atomic layer deposition equipment via a pipeline. The source bottle was heated to 50°C, and nitrogen carrier gas was introduced at a flow rate of 200 sccm. Compound a was introduced into the reaction chamber in a pulsed manner for 6 s to allow compound a to chemically adsorb onto the substrate. Subsequently, nitrogen gas was introduced into the reaction chamber for 30 s to purge it, and the first reaction product was obtained on the substrate. (3) Nitrogen plasma gas is introduced into the reaction chamber at a flow rate of 200 sccm for 30 s to obtain a doped silicon nitride thin film. Repeat steps (2)-(3) 200 times to obtain a phosphorus and carbon doped silicon nitride film with a thickness of 477 Å on the substrate. After the first cycle, the substrate in step (2) is the doped silicon nitride film obtained in step (3) of the previous cycle.
[0077] Comparative Example 2 The difference between Comparative Example 2 and Example 5 is that Comparative Example 2 uses a phosphine-free silicon precursor, specifically including: (1) Place the silicon wafer into the reaction chamber, set the reaction chamber temperature to 350℃ and the pressure to 150Pa; (2) Diisopropylaminosilane was placed in a stainless steel source bottle. The source bottle was connected to the reaction chamber of the atomic layer deposition equipment through a pipeline. The heating temperature of the source bottle was 50°C. Nitrogen carrier gas was introduced with a flow rate of 200 sccm. Diisopropylaminosilane was introduced into the reaction chamber in a pulsed manner for 6 s to allow the precursor to chemically adsorb onto the substrate. Nitrogen gas was then introduced into the reaction chamber for 30 s to purge it, and the first reaction product was obtained on the substrate. (3) Copper chloride was placed in a stainless steel source bottle, which was connected to the reaction chamber of the atomic layer deposition equipment via a pipeline. The source bottle was heated to 50°C. Nitrogen carrier gas was introduced at a flow rate of 200 sccm. Copper chloride was introduced into the reaction chamber in a pulsed manner for 6 seconds to allow the copper chloride to chemically adsorb with the first reaction product. Then, nitrogen gas was introduced into the reaction chamber for 30 seconds to purge and obtain the second reaction product. (4) Nitrogen plasma gas is introduced into the reaction chamber at a flow rate of 200 sccm for 30 s to obtain a doped silicon nitride thin film. Repeat steps (2)-(4) 200 times to obtain a copper- and carbon-doped silicon nitride film with a thickness of 458 Å on the substrate. After the first cycle, the substrate in step (2) is the silicon nitride film obtained in step (4) of the previous cycle.
[0078] Experimental Example The silicon nitride films prepared in the above examples and comparative examples were tested for density and elemental content (doped metal, C, Si, N) according to the following methods. The doped metal is the metal corresponding to the metal salt compound deposited in the examples. The results are shown in Table 2.
[0079] (1) Density test: The density of the film thickness was tested using an X-ray reflectometer (XRR, model Malvern Panalytical X'PertPRO).
[0080] (2) Element content test: The elemental composition of the thin film was tested using an XPS tester (ThermoFisher EscaLab Xi+). Since hydrogen and helium lack inner electron energy levels, XPS cannot detect hydrogen and helium. The element content measured by XPS in Table 2 is relative to the content of all elements except hydrogen and helium.
[0081] Table 2 Test Results
[0082] As shown in Table 1, the density of the metal-phosphorus-doped silicon nitride thin film prepared in this application is as high as 6.0 g / cm³. 3The above results indicate that, relative to all elements except hydrogen and helium, the total content of silicon, nitrogen, carbon, phosphorus, and doped metal elements in the silicon nitride film reaches over 99 wt%. The silicon nitride films prepared in Examples 5-12 have densities of 6.05-6.33 g / cm³. 3 Compared to all elements except hydrogen and helium, the total content of silicon, nitrogen, carbon, phosphorus, and doped metal elements in the silicon nitride film is 99-99.9 wt%, indicating relatively few impurities. Furthermore, compared to Example 5, Comparative Example 1 used only compound a as a precursor for atomic deposition, resulting in a silicon nitride film with a density of only 2.32 g / cm³. 3 Compared to all elements except hydrogen and helium, the combined content of silicon, nitrogen, carbon, phosphorus, and doped metal elements in the silicon nitride film is also lower than in Example 5. In contrast to Example 5, Comparative Example 2, which uses phosphorus-free nitrosilanes and metal salt compounds for atomic lamination, yielded a silicon nitride film with a density of only 2.25 g / cm³. 3 Compared to all elements except hydrogen and helium, the total content of silicon, nitrogen, carbon, phosphorus and doped metal elements in the silicon nitride film is 98.81 wt%, which is much lower than that in Example 5.
[0083] In summary, during the preparation of doped silicon nitride thin films, this invention increases the density of silicon nitride thin films and reduces impurities by introducing silicon precursors containing phosphine and amino groups and metals into the deposition reaction, thereby obtaining better semiconductor device performance.
[0084] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.
[0085] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.
[0086] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.
Claims
1. A silicon precursor composition for preparing silicon nitride thin films, characterized in that, The silicon precursor composition comprises a phosphorus-containing compound with a structure as shown in Formula I and / or Formula II. ； Formula I; Formula II; R1', R2', R3', R4', R5' and R6' are each independently selected from diphenylphosphine, diethylphosphine, dimethylphosphine, phenylphosphine, dicyclopentylphosphine, di(2-furanyl)phosphine, (diphenylphosphinemethyl)diphenylphosphine or (diphenylphosphineethyl)diphenylphosphine.
2. The silicon precursor composition according to claim 1, characterized in that, The phosphorus-containing compound is selected from one or more of the following: di(diphenylphosphine)aminosilane, di(diethylphosphine)aminosilane, di(dimethylphosphine)aminosilane, bis(di(dimethylphosphine)amino)silane, bis(di(dicyclopentylphosphine)amino)silane, bis(di(diethylphosphine)amino)silane, or bis(di(diphenylphosphine)amino)silane. Preferably, the phosphorus-containing compound is selected from one or more of the following groups of compounds: ； Compound a, Compound b, Compound c, Compound d.
3. A method for preparing a doped silicon nitride thin film, characterized in that, Includes the following steps: (1) Provide a substrate in the reaction chamber; (2) The silicon precursor composition of claim 1 or 2 is introduced into the reaction chamber by atomic layer deposition, so that it is chemically adsorbed onto the substrate surface to form a first reaction product on the substrate surface; (3) Metal inorganic salts are introduced into the reaction chamber by atomic layer deposition, so that they are chemically adsorbed with the first reaction product to obtain the second reaction product; (4) Introduce nitrogen source plasma gas into the reaction chamber to react with the second reaction product to obtain a doped silicon nitride thin film.
4. The preparation method according to claim 3, characterized in that, The preparation method includes repeating steps (2) to (4) at least twice; preferably repeating steps (2) to (4) 2-100 times.
5. The preparation method according to claim 3 or 4, characterized in that, In step (2), the silicon precursor composition is introduced into the reaction chamber in a pulsed manner using a carrier gas; Preferably, the carrier gas is selected from one or more of nitrogen, argon, helium or krypton, and the preferred flow rate of the carrier gas is 100-500 sccm. More preferably, the temperature of the reaction chamber in step (2) is 250-450°C, and the pressure of the reaction chamber is preferably 150-550 Pa; More preferably, the time for the silicon precursor composition to chemically adsorb onto the substrate is 2-10 seconds.
6. The preparation method according to any one of claims 3-5, characterized in that, The inorganic metal salt in step (3) includes one or more of aluminum chloride, gallium chloride, indium chloride, copper chloride or thallium chloride, preferably copper chloride.
7. The preparation method according to any one of claims 3-6, characterized in that, In step (3), the metal inorganic salt is introduced into the reaction chamber in a pulsed manner using a carrier gas; Preferably, the carrier gas is selected from one or more of nitrogen, argon, helium or krypton, and the preferred flow rate of the carrier gas is 100-500 sccm. More preferably, the temperature of the reaction chamber in step (3) is 250-450°C, and the pressure of the reaction chamber is preferably 150-550 Pa; More preferably, the reaction time between the metal salt compound and the first reaction product is 2-10 seconds.
8. The preparation method according to any one of claims 3-7, characterized in that, In step (4), the nitrogen source plasma gas is selected from nitrogen plasma gas and / or ammonia plasma gas; Preferably, the flow rate of the nitrogen source plasma gas is 100-500 sccm; More preferably, the reaction time between the nitrogen source plasma gas and the second reaction product is 10-60 s; More preferably, the temperature of the reaction in step (4) is 250-450°C, and the preferred reaction pressure is 150-550 Pa.
9. A silicon nitride doped thin film, characterized in that, The doped silicon carbide thin film is prepared by the preparation method comprising any one of claims 4-8; Preferably, the density of the doped silicon carbide thin film is 6.0-6.5 g / cm³. 3 ; More preferably, in the doped silicon carbide film, the sum of the contents of silicon, nitrogen, carbon, phosphorus and doped metal elements in the doped silicon nitride film is greater than or equal to 99 wt% relative to all elements except hydrogen and helium.
10. The application of the doped silicon nitride thin film of claim 9 in the semiconductor industry and / or microelectronics field.