Method for producing titanium oxynitride film
Patent Information
- Application Number
- CN202610837839.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-06-10
- Publication Date
- 2026-08-28
AI Technical Summary
然而，通过这种方式形成的TiON薄膜中氧含量很低，难以满足较高氧含量应用场景的需求
[0020] This application integrates oxygen doping into the purging step by alternately supplying titanium-containing precursors and nitrogen-containing reactive gases into the ALD reaction chamber, and purging with a mixture of inert gas and oxygen after each gas supply step. This achieves one-step purging and oxidation doping, which is beneficial for increasing the oxygen content in the titanium oxynitride film while achieving uniform oxygen doping at the atomic level. The method of this application is simple, does not require an additional independent oxidation step, has no risk of plasma damage, and has excellent step coverage for high aspect ratio structures.
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Figure CN122648906A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of semiconductor devices and integrated circuit technology, and in particular to a method for preparing a titanium oxynitride thin film. Background Technology
[0002] Titanium oxynitride (TiON) films are an important class of semiconductor functional materials, combining the excellent conductivity and high hardness of titanium nitride (TiN) with the chemical stability of titanium oxide (TiO2). They are widely used in integrated circuit manufacturing, for example, as diffusion barrier layers in copper interconnects, work function adjustment layers for metal gates, and adhesion layers. As the feature size of semiconductor devices continues to shrink, the quality requirements for TiON films are becoming increasingly stringent, particularly regarding oxygen content, film uniformity, and step coverage.
[0003] In related technologies, plasma-enhanced atomic layer deposition (PEALD) is one of the commonly used methods for preparing TiON thin films. It uses tetrakis(dimethylamino)titanium (TDMAT, Ti(N(CH3)2)4) as a titanium-containing precursor and oxygen as the oxygen source. In one deposition cycle, TDMAT pulses, nitrogen purging, oxygen plasma pulses, and a second purging are performed sequentially, and this cycle is repeated. However, the TiON thin films formed in this way have very low oxygen content, making it difficult to meet the requirements of applications with high oxygen content. Furthermore, this method uses plasma-assisted deposition, and the high-energy ions in the plasma may damage the substrate. Additionally, this method exhibits poor step coverage in high aspect ratio structures. Summary of the Invention
[0004] This application provides a method for preparing titanium oxynitride thin films, which is beneficial for increasing the oxygen content in titanium oxynitride thin films while achieving uniform oxygen doping at the atomic level.
[0005] In view of this, this application provides a method for preparing a titanium oxynitride thin film, comprising:
[0006] S1, Place the substrate in the reaction chamber and heat it to the process temperature;
[0007] S2, supply titanium-containing precursor gas into the reaction chamber, at least a portion of the titanium-containing precursor gas is adsorbed on the surface of the substrate to form an adsorption layer;
[0008] S3, using a mixture of inert gas and oxygen as the purge gas, the reaction chamber is purged, and unadsorbed titanium-containing precursor gas and byproducts are removed, and oxygen is introduced into the adsorption layer.
[0009] S4, nitrogen-containing reactive gas is supplied into the reaction chamber to carry out the reaction and form a thin film layer with a titanium-oxygen-nitrogen bonded structure;
[0010] S5, using the mixture of the inert gas and oxygen as the purging gas, the reaction chamber is purged, unreacted nitrogen-containing reaction gas and byproducts are removed, and oxygen is further introduced into the thin film layer;
[0011] S6. Repeat steps S2-S5 for a preset number of cycles to form a titanium oxynitride film.
[0012] Optionally, the inert gas is at least one of argon, helium, and nitrogen.
[0013] Optionally, the titanium-containing precursor is at least one of titanium tetrachloride and titanium tetrabromide.
[0014] Optionally, the nitrogen-containing reactive gas is at least one of ammonia and monomethylhydrazine.
[0015] Optionally, the purging time is 0.1s-1s.
[0016] Optionally, the volume fraction of oxygen in the mixed gas is 1%-20%.
[0017] Optionally, the oxygen content in the obtained titanium oxynitride film can be adjusted by controlling the volume fraction of oxygen in the mixed gas and / or the purging time.
[0018] Optionally, the process temperature is 300℃~500℃, and the chamber pressure is 0.1 Torr~10 Torr.
[0019] The technical solution of this application has at least the following advantages:
[0020] This application integrates oxygen doping into the purging step by alternately supplying titanium-containing precursors and nitrogen-containing reactive gases into the ALD reaction chamber, and purging with a mixture of inert gas and oxygen after each gas supply step. This achieves one-step purging and oxidation doping, which is beneficial for increasing the oxygen content in the titanium oxynitride film while achieving uniform oxygen doping at the atomic level. The method of this application is simple, does not require an additional independent oxidation step, has no risk of plasma damage, and has excellent step coverage for high aspect ratio structures. Attached Figure Description
[0021] To more clearly illustrate the technical solutions in the specific embodiments of this application or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.
[0022] Figure 1 This is a flowchart of a method for preparing a titanium oxynitride thin film according to an exemplary embodiment of this application; Detailed Implementation
[0023] The technical solutions of this application will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0024] In the description of this application, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.
[0025] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal connection of two components; and they can refer to a wireless connection or a wired connection. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.
[0026] Furthermore, the technical features involved in the different embodiments of this application described below can be combined with each other as long as they do not conflict with each other.
[0027] The following is combined Figure 1 This describes an embodiment of the present application.
[0028] refer to Figure 1 The illustration shows an embodiment of this application, providing a method for preparing a titanium oxynitride thin film, comprising:
[0029] S1, place the substrate in the reaction chamber and heat it to the process temperature.
[0030] For example, the substrate may be a silicon substrate, a germanium (Ge) substrate, a gallium arsenide (GaAs) substrate, or other materials suitable for semiconductor device fabrication, and the reaction chamber may be a chamber in a thermal atomic layer deposition (ALD) apparatus.
[0031] In some embodiments, the process temperature is 300°C to 500°C, and the chamber pressure is 0.1 Torr to 10 Torr.
[0032] For example, the process temperature can be 300°C, 350°C, 450°C, 500°C, etc., and the chamber pressure can be 0.1 Torr, 1 Torr, 5 Torr, 10 Torr, etc.
[0033] S2, supply titanium-containing precursor gas into the reaction chamber, at least part of the titanium-containing precursor gas is adsorbed on the substrate surface to form an adsorption layer.
[0034] For example, the titanium-containing precursor gas can be titanium tetrachloride (TiCl4) or titanium tetrabromide (TiBr4) gas, and the dosage time of the titanium-containing precursor gas should be sufficient to form a saturated adsorption layer on the substrate surface, for example, 0.1s-0.5s.
[0035] S3, using a mixture of inert gas and oxygen as the purge gas, purges the reaction chamber, removing unadsorbed titanium-containing precursor gas and byproducts, and introducing oxygen into the adsorption layer.
[0036] For example, the inert gas can be argon (Ar), and in addition to argon, the inert gas can also be helium (He) or nitrogen (N2).
[0037] In some embodiments, the volume fraction of oxygen in the gas mixture is 1%-20%.
[0038] For example, the volume fraction of oxygen in the gas mixture can be 1%, 5%, 10%, 15%, 20%, etc.
[0039] In some embodiments, the purging time of the reaction chamber using purging gas is 0.1s-1s.
[0040] For example, the purging time can be 0.1s, 0.2s, 0.5s, 1s, etc.
[0041] The resulting titanium oxynitride (TiN) can be adjusted by controlling the volume fraction of oxygen in the mixed gas and / or the purging time. x O y The oxygen content in the thin film.
[0042] For example, when the volume fraction of oxygen in the mixed gas is 5% and the purging time is 0.2 s, the oxygen content in the obtained titanium oxynitride film is 14.2 at.
[0043] It should be noted that after the supply of titanium-containing precursor gas is stopped, the reaction chamber is purged with a mixture of inert gas and oxygen.
[0044] S4, nitrogen-containing reactive gas is supplied into the reaction chamber to carry out the reaction and form a thin film layer with a titanium-oxygen-nitrogen bond structure.
[0045] For example, the nitrogen-containing reactive gas can be ammonia (NH3) or monomethylhydrazine (MMH). The dosage and time of the nitrogen-containing reactive gas should be sufficient to allow it to react fully with the adsorbed layer, for example, 0.2s-0.6s.
[0046] It should be noted that nitrogen-containing reaction gas is supplied to the reaction chamber only after the purge gas supply has stopped.
[0047] S5 uses a mixture of inert gas and oxygen as a purge gas to purge the reaction chamber, removing unreacted nitrogen-containing reaction gases and byproducts, and further introducing oxygen into the thin film layer.
[0048] It should be noted that the purging gas and purging time in this step are the same as in step S3.
[0049] S6. Repeat steps S2-S5 for a preset number of cycles to form a titanium oxynitride film.
[0050] It should be noted that the chemical composition of this titanium oxynitride thin film can be represented as TiN. x O y For simplicity, it is usually referred to as TiON.
[0051] In related technologies, plasma-enhanced atomic layer deposition (PEALD) is one of the commonly used methods for preparing TiON thin films. It uses tetrakis(dimethylamino)titanium (TDMAT, Ti(N(CH3)2)4) as a titanium-containing precursor and oxygen as the oxygen source. In one deposition cycle, TDMAT pulses, nitrogen purging, oxygen plasma pulses, and a second purging are performed sequentially, and this cycle is repeated. However, the oxygen content in TiON films formed in this way is very low, typically only around 1.5 at%, which is insufficient for applications requiring higher oxygen content. Furthermore, this method uses plasma-assisted deposition, where high-energy ions may damage the substrate, and it exhibits poor step coverage in high aspect ratio structures.
[0052] In related technologies, a "deposition followed by oxidation" approach can be adopted. First, a pure TiN sublayer is deposited through multiple atomic layer deposition (ALD) cycles. Then, an oxidation step (such as O2, O3, or H2O) is introduced to oxidize the entire sublayer into TiON to obtain a TiON film with a high oxygen content (≥50 at%). However, the TiON film obtained by this method requires an additional oxidation step after the formation of the TiN sublayer, which increases the process complexity and makes it difficult to achieve uniform doping in each atomic layer during the oxidation process.
[0053] This application integrates oxygen doping into the purging step by alternately supplying titanium-containing precursors and nitrogen-containing reactive gases into the ALD reaction chamber, and purging with a mixture of inert gas and oxygen after each gas supply step. This achieves one-step purging and in-situ oxidation doping, which is beneficial for increasing the oxygen content in TiON films while achieving atomic-level uniform distribution of oxygen elements in the film thickness direction (i.e., achieving uniform oxygen doping at the atomic level). The method of this application is simple, does not require the introduction of an additional independent oxidation step, has no risk of plasma damage, and has excellent step coverage for high aspect ratio structures.
[0054] To verify the technical effect of this application, the inventors used X-ray photoelectron spectroscopy (XPS) to analyze the composition of the films prepared by the methods provided in Example 1 and Comparative Examples 1-2, and the oxygen content in the films is shown in Table 1.
[0055] Example 1:
[0056] This embodiment provides a method for preparing a titanium oxynitride thin film, including:
[0057] S1, place the substrate in the reaction chamber and heat it to the process temperature.
[0058] In this embodiment, the substrate is a silicon substrate, the process temperature is 400°C, and the reaction chamber pressure is 1 Torr.
[0059] S2, supply titanium-containing precursor gas into the reaction chamber, at least part of the titanium-containing precursor gas is adsorbed on the substrate surface to form an adsorption layer.
[0060] In this embodiment, the titanium-containing precursor gas is titanium tetrachloride gas, and in this step, titanium tetrachloride gas is introduced into the reaction chamber for 0.2s.
[0061] S3, using a mixture of inert gas and oxygen as the purge gas, purges the reaction chamber, removing unadsorbed titanium-containing precursor gas and byproducts, and introducing oxygen into the adsorption layer.
[0062] In this embodiment, the inert gas is argon, the volume fraction of oxygen in the mixed gas is 5%, and the purging gas purging time of the reaction chamber is 0.2s.
[0063] S4, nitrogen-containing reactive gas is supplied into the reaction chamber to carry out the reaction and form a thin film layer with a titanium-oxygen-nitrogen bond structure.
[0064] In this embodiment, the nitrogen-containing reaction gas is ammonia, and ammonia is introduced into the reaction chamber for 0.3 seconds in this step.
[0065] S5 uses a mixture of inert gas and oxygen as a purge gas to purge the reaction chamber, removing unreacted nitrogen-containing reaction gases and byproducts, and further introducing oxygen into the thin film layer.
[0066] In this embodiment, the purging gas and purging time in this step are the same as in step S3.
[0067] S6. Repeat steps S2-S5 for the preset number of cycles.
[0068] In this embodiment, the preset number of cycles is 200.
[0069] Comparative Example 1:
[0070] The only difference between this comparative example and Example 1 is that steps S3 and S5 are replaced with argon gas as the purging gas to purge the reaction chamber.
[0071] Comparative Example 2:
[0072] This comparative example provides a method for preparing a TiON thin film, including:
[0073] S1, place the substrate in the reaction chamber and heat it to the process temperature.
[0074] In this comparative example, the substrate is a silicon substrate, the process temperature is 250℃, and the reaction chamber pressure is 0.5 Torr.
[0075] S2 supplies titanium-containing precursor gas into the reaction chamber.
[0076] In this comparative example, the titanium-containing precursor gas is TDMAT, and TDMAT vapor is introduced into the reaction chamber for 0.5 s in this step.
[0077] S3 uses an inert gas as the purging gas to purge the reaction chamber.
[0078] In this comparative example, the inert gas was nitrogen, and the purging time was 0.5 s.
[0079] S4 supplies oxygen plasma into the reaction chamber.
[0080] In this comparative example, the oxygen source is oxygen, the radio frequency power is 300W, the O2 flow rate is 200sccm, and the oxygen plasma pulse time is 1.0s.
[0081] S5 uses an inert gas as the purging gas to purge the reaction chamber.
[0082] In this comparative example, the purging gas was nitrogen, and the purging time was 0.5 s.
[0083] S6. Repeat steps S2 to S5 a total of 200 times.
[0084] Table 1
[0085] Example 1 Comparative Example 1 Comparative Example 2 Oxygen content (at%) 14 ＜1 1.5
[0086] As can be seen from Table 1, the oxygen content of the TiON film prepared in Example 1 is significantly higher than that of Comparative Example 1 and Comparative Example 2.
[0087] 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 application.
Claims
1. A method for preparing a titanium oxynitride thin film, characterized in that, include: S1, Place the substrate in the reaction chamber and heat it to the process temperature; S2, supply titanium-containing precursor gas into the reaction chamber, at least a portion of the titanium-containing precursor gas is adsorbed on the surface of the substrate to form an adsorption layer; S3, using a mixture of inert gas and oxygen as the purge gas, the reaction chamber is purged, and unadsorbed titanium-containing precursor gas and byproducts are removed, and oxygen is introduced into the adsorption layer. S4, nitrogen-containing reactive gas is supplied into the reaction chamber to carry out the reaction and form a thin film layer with a titanium-oxygen-nitrogen bonded structure; S5, using the mixture of the inert gas and oxygen as the purging gas, the reaction chamber is purged, unreacted nitrogen-containing reaction gas and byproducts are removed, and oxygen is further introduced into the thin film layer; S6. Repeat steps S2-S5 for a preset number of cycles to form a titanium oxynitride film.
2. The method according to claim 1, characterized in that, The inert gas is at least one of argon, helium, and nitrogen.
3. The method according to claim 1, characterized in that, The titanium-containing precursor is at least one of titanium tetrachloride and titanium tetrabromide.
4. The method according to claim 1, characterized in that, The nitrogen-containing reactive gas is at least one of ammonia and monomethylhydrazine.
5. The method according to claim 1, characterized in that, The purging time is 0.1s-1s.
6. The method according to claim 1, characterized in that, The volume fraction of oxygen in the mixed gas is 1%-20%.
7. The method according to claim 1, characterized in that, The oxygen content in the obtained titanium oxynitride film is adjusted by controlling the volume fraction of oxygen in the mixed gas and / or the purging time.
8. The method according to claim 1, characterized in that, The process temperature is 300℃~500℃, and the chamber pressure is 0.1 Torr~10 Torr.