Method for depositing Group VI transition metal nitride films

Abstract

We provide high-quality metal nitride films. [Solution] A film deposition method for forming a VI transition metal nitride film on a substrate placed in a film deposition chamber, wherein an organic group VI transition metal is supplied to the film deposition chamber, a nitride source compound different from the organic group VI transition metal is supplied to the film deposition chamber, and the VI transition metal nitride film is formed on the substrate, which is maintained at a temperature of 936°C or lower, from the nitride source compound supplied to the film deposition chamber and the organic group VI transition metal.

Description

[Technical Field]

[0001] The present invention relates to a method for forming a single-composition group VI transition metal nitride (e.g., Mo2N) film with excellent crystallinity. [Background technology]

[0002] Mo (molybdenum) possesses excellent physical properties such as a high melting point, low thermal expansion coefficient, low resistivity, and high thermal conductivity. Therefore, it is used in the manufacture of semiconductor devices for diffusion barriers, electrodes, photomasks, power electronics device substrates, and low-resistance gates and connects. Mo2N is used as a good barrier film against copper diffusion in microelectronic circuits. It is used in electrodes for thin-film capacitors and field-effect transistors.

[0003] Chemical Vapor Deposition (2001), 7(5), 219-224 discloses an oxide film (with W(=O)(OtBu)4 as the precursor).

[0004] Solar Energy Materials and Solar Cells, 2001, 68, 239 discloses an oxide film (with W(=O)(OnBu)4 as a precursor).

[0005] U.S. Patent No. 7,560,581 discloses nitride films (with bis-alkylimide-bis-dialkylaminotungsten as a precursor).

[0006] J.Mat.Res.9(7),1994,1622-1624 discloses a nitride film (with Mo(NtBu)2(NHtBu)2 as the precursor).

[0007] Japanese Patent No. 6670824 discloses "a group 6 film-forming composition for use in film formation by vapor-phase thin-film deposition, comprising a group 6 transition metal-containing precursor selected from the group consisting of M(=O)2(NR2)2 (wherein M is Mo, R is SiR'3, R' is H or a C1-C6 alkyl group) and M(=NR)2(OR)2 (wherein M is Mo, R is H or a C1-C6 alkyl group)" and "a method for depositing a group 6 transition metal-containing film on a substrate, comprising the steps of introducing a vapor of the group 6 film-forming composition into a reactor having a substrate disposed therein, and depositing at least a portion of the group 6 transition metal-containing precursor onto the substrate." However, the film disclosed in this patent specification is an oxide film. There is no mention of a nitride film.

[0008] The aforementioned literature does not disclose that precursors (group VI transition metal materials) having alkoxy groups (ORs) are preferable as nitride film-forming materials. Furthermore, it does not disclose a method for forming a single-composition nitride film with excellent crystallinity using precursors having alkoxy groups. [Prior art documents] [Patent Documents]

[0009] [Patent Document 1] U.S. Patent No. 7,560,581 [Patent Document 2] Patent No. 6670824 [Non-patent literature]

[0010] [Non-Patent Document 1] Chemical Vapor Deposition(2001),7(5),219-224 [Non-Patent Document 2] Solar Energy Materials and Solar Cells,2001,68,239 [Non-Patent Document 3] J.Mat.Res.9(7),1994,1622-1624 [Overview of the Initiative]

Problems to be Solved by the Invention

[0011] When forming a film using a material having a self-oxidizing source as a precursor (for example, a metal alkoxide compound), it will be easily understood that a film containing oxygen (for example, an oxide film or an oxynitride film) is preferentially formed. Therefore, in order to form a nitride film of a single composition, it is difficult to say that a material having a self-oxidizing source is suitable as a precursor. Therefore, when a material having a self-oxidizing source is selected as a precursor, it can be easily imagined that a different technique is required to form a nitride film of a single composition.

[0012] The problem to be solved by the present invention is to provide a technique for forming a metal nitride film of a single composition with excellent crystallinity when forming a film using an organometallic compound having oxygen (О) as a precursor.

Means for Solving the Problems

[0013] The present invention is a film forming method in which a Group VI transition metal nitride film is formed on a substrate disposed in a film forming chamber, where an organo Group VI transition metal is supplied into the film forming chamber, a nitride source compound different from the organo Group VI transition metal is supplied into the film forming chamber, and the Group VI transition metal nitride film is formed from the nitride source compound and the organo Group VI transition metal supplied into the film forming chamber on the substrate maintained at a temperature of 936 °C or lower. A film forming method is proposed. <00​​​​​​​​​​The present invention proposes a film formation method in which the temperature of the substrate is preferably 350 °C or higher.

[0017] The present invention proposes a film formation method in which preferably, the organic Group VI transition metal is supplied after the nitride source compound is supplied into the film formation chamber.

[0018] The present invention proposes a film formation method in which preferably, the pressure in the film formation chamber is 800 Pa or less.

[0019] The present invention proposes a film formation method in which preferably, substantially no hydrogen is supplied into the film formation chamber.

[0020] The present invention proposes a film formation method in which preferably, CVD is used for film formation.

[0021] The present invention proposes a film formation method in which preferably, laser CVD is used for film formation.

[0022] The present invention proposes a film formation method in which preferably, the nitride source compound is NR 1 R 2 R 3 (R 1 ,R 2 ,R 3 is a group selected from the group consisting of H and an alkyl group having 3 or less carbon atoms).

[0023] The present invention proposes a film formation method in which preferably, the nitride source compound is ammonia.

[0024] The present invention proposes a film formation method in which preferably, the organic group of the organic Group VI transition metal has O.

[0025] The present invention proposes a film formation method in which preferably, the organic group of the organic Group VI transition metal has O and N.

[0026] The present invention proposes a film deposition method in which the organic group VI transition metal is, for example, (tBuN)2M(OtAm)2 [where M is a group VI transition metal].

[0027] The present invention proposes a film deposition method in which the organic group VI transition metal is, for example, (tBuN)2M(OiPr)(OtAm) [where M is a group VI transition metal].

[0028] The present invention proposes a film formation method in which the organic group VI transition metal is, for example, (tBuN)2M(OR2)(OR3) [where M is a group VI transition metal, and R2 and R3 are alkyl groups having 2 to 5 carbon atoms].

[0029] The present invention proposes a film formation method in which the organic group VI transition metal is, for example, (R1N)2M(OR2)(OR3))[M is a group VI transition metal, and R1, R2, and R3 are alkyl groups having 2 to 5 carbon atoms].

[0030] The present invention proposes a film formation method in which the alkyl group in the organo-VI transition metal is preferably a branched alkyl group.

[0031] The present invention proposes a film deposition method wherein the deposited VI transition metal nitride film is a single-phase film. [Effects of the Invention]

[0032] According to the present invention, high-quality metal nitride films were obtained. For example, a single-composition group VI transition metal nitride film with excellent crystallinity was obtained. [Brief explanation of the drawing]

[0033] [Figure 1] Schematic diagram of the vapor deposition apparatus [Figure 2] XRD diffraction pattern of Example 1 [Figure 3] XRD diffraction pattern of Example 3 [Figure 4] XRD diffraction pattern of Reference Example 1 [Figure 5] XRD diffraction pattern of Example 5 [Figure 6] XRD diffraction pattern of Example 7 [Figure 7] XRD diffraction pattern of Example 8 [Modes for carrying out the invention]

[0034] The following detailed description provides only preferred exemplary embodiments and is not intended to limit the scope, applicability, or configuration of the invention. Rather, it provides to those skilled in the art an explanation for carrying out / enabling preferred exemplary embodiments of the invention. Various modifications can be made to the function and arrangement of the elements without departing from the spirit and scope of the invention as set forth in the appended claims.

[0035] The present invention relates to a film deposition method for forming a VI transition metal nitride film. The method involves forming a VI transition metal nitride film on a substrate placed in a film deposition chamber. The metal of the VI transition metal nitride film is, for example, Mo, or W. The deposited metal nitride film was, for example, a single-phase film. For example, it was a single-composition transition metal nitride film with excellent crystallinity. The method includes a nitride source compound supply step in which a nitride source compound is supplied into the film deposition chamber. The method also includes an organic VI transition metal supply step in which an organic VI transition metal (precursor) is supplied into the film deposition chamber. A carrier gas (for example, N2) is supplied to the precursor, and the precursor is transported into the film deposition chamber by bubbling. The nitride source compound supply step and the organic VI transition metal supply step may be performed in any order, or simultaneously. However, preferably, the organic VI transition metal is supplied after the nitride source compound is supplied into the film deposition chamber. The method includes a step of heating the substrate (also called a substrate or base). The conditions within the deposition chamber (temperature, pressure, and especially temperature) affected the reaction between the precursor supplied to the deposition chamber and NH3. Specifically, the composition of the deposited film varied significantly depending on the substrate temperature. At temperatures exceeding 936°C, a single-composition group VI transition metal nitride film with excellent crystallinity could not be obtained. For the deposition of a metal nitride film, it was important that the substrate temperature was 936°C or lower (particularly below 935°C). The lower limit of the temperature was preferably 300°C, more preferably 350°C or higher. By controlling (maintaining) the temperature under these conditions, the group VI transition metal nitride film was deposited on the substrate from the nitride source compound and the organic group VI transition metal supplied to the deposition chamber. By-products in the deposition process were removed by a carrier gas passing through the deposition chamber. The pressure within the deposition chamber was preferably 800 Pa or lower, more preferably 700 Pa or lower, and even more preferably 500 Pa or lower. More preferably, the pressure was 300 Pa or less. Particularly preferably, it was 200 Pa or less. In the embodiments described later, ammonia and the precursor are supplied at equal pressure, but 1 / 4 ≤ (ammonia supply pressure / precursor supply pressure) ≤ 4 / 1 is also acceptable.Preferably, 1 / 2 ≦ (ammonia supply pressure / precursor supply pressure). More preferably, 1 ≦ (ammonia supply pressure / precursor supply pressure). CVD technology was used for film formation. In particular, laser CVD technology was used. By-products in the deposition process are removed by a carrier gas passing through the film formation chamber. The precursor was, for example, a Group VI transition metal organic compound having O and N. Preferably, for example, (R1N)2M(OR2)(OR3) [R1, R2, and R3 are alkyl groups having 2 to 5 carbon atoms]. For example, (tBuN)2M(OR2)(OR3) [R2 and R3 are alkyl groups having 2 to 5 carbon atoms]. The alkyl group was preferably a branched alkyl group. For example, (tBuN)2M(OiPr)(OtAm). For example, (tBuN)2M(OtAm)2. M was, for example, Mo or W. The nitrogen source compound was, for example, NR 1 R 2 R 3 (R 1 ,R 2 ,R 3 (R, R, and R are groups selected from the group consisting of H and alkyl groups having 3 or fewer carbon atoms). Ammonia was preferred. And by the above method, a high-quality metal nitride film was deposited on the substrate.

[0036] The present invention will be described more specifically below. The following description is only a preferred exemplary embodiment, and the present invention is not limited thereto. Various changes are included without departing from the spirit and scope of the present invention defined in the claims.

[0037] [Example 1] NH3 was supplied (100 sccm) into the deposition chamber (reactor), and the pressure inside the deposition chamber was adjusted to 60 Pa. The Si substrate placed inside the deposition chamber was heated to 578°C by a semiconductor laser. After this, the precursor ((tBuN)2Mo(OtAm)2[bis(t-amyloxy)bis(t-butylimide)molybdenum]) was supplied (50 sccm) into the deposition chamber (reactor), and the pressure inside the deposition chamber was adjusted to 120 Pa. The precursor was heated to 50°C. The precursor was supplied by bubbling N2 gas. As a result, a film was formed on the Si substrate. According to X-ray diffraction (XRD), the aforementioned film was a highly crystalline Mo metal nitride film. The XRD diffraction pattern is shown in Figure 2. In addition to the peaks originating from the Si substrate, diffraction peaks at (111), (200), and (220) were observed. These are characteristic diffraction peaks that appear in the c-Mo2N phase. Therefore, it is composed solely of the Mo nitride phase. In other words, the film was a single highly crystalline Mo metal nitride film (c-Mo2N).

[0038] [Example 2] The procedure was carried out in the same manner as in Example 1, except that the heating temperature of the Si substrate was changed to 774°C. As a result, a film was formed on the Si substrate. According to X-ray diffraction (XRD), the aforementioned film was a highly crystalline Mo metal nitride film. In addition to the peaks originating from the Si substrate, diffraction peaks at (111), (200), and (220) were observed. These are characteristic diffraction peaks that appear in the c-Mo2N phase. Therefore, it is composed solely of the Mo nitride phase. In other words, the film was a single highly crystalline Mo metal nitride film (c-Mo2N).

[0039] [Example 3] The procedure was carried out in the same manner as in Example 1, except that the heating temperature of the Si substrate was changed to 895°C. As a result, a film was formed on the Si substrate. According to X-ray diffraction (XRD), the aforementioned film was a highly crystalline Mo metal nitride film. The XRD diffraction pattern is shown in Figure 3. In addition to the peaks originating from the Si substrate, diffraction peaks at (111), (200), and (220) were observed. These are characteristic diffraction peaks that appear in the c-Mo2N phase. Therefore, it is composed solely of the Mo nitride phase. In other words, the film was a single highly crystalline Mo metal nitride film (c-Mo2N).

[0040] [Example 4] The procedure was carried out in the same manner as in Example 1, except that the heating temperature of the Si substrate was changed to 932°C. As a result, a film was formed on the Si substrate. According to X-ray diffraction (XRD), the aforementioned film was a highly crystalline Mo metal nitride film. In addition to the peaks originating from the Si substrate, diffraction peaks at (111), (200), and (220) were observed. These are characteristic diffraction peaks that appear in the c-Mo2N phase. Therefore, it is composed solely of the Mo nitride phase. In other words, the film was a single highly crystalline Mo metal nitride film (c-Mo2N).

[0041] [Reference example 1] The procedure was carried out in the same manner as in Example 1, except that the heating temperature of the Si substrate was changed to 937°C. As a result, a film was formed on the Si substrate. X-ray diffraction (XRD) analysis of the aforementioned film revealed diffraction peaks (110), (200), (211), (111), and (220) in addition to the peak originating from the Si substrate. The XRD diffraction pattern is shown in Figure 4. The (110), (200), and (211) peaks are characteristic diffraction peaks that appear in the Mo metallic phase. The (111), (200), and (220) diffraction peaks are characteristic diffraction peaks that appear in the c-Mo2N phase. Therefore, the film produced in this example contained a mixture of Mo metallic and Mo nitride phases.

[0042] [Reference example 2] The procedure was carried out in the same manner as in Example 1, except that the heating temperature of the Si substrate was changed to 958°C. As a result, a film was formed on the Si substrate. X-ray diffraction (XRD) of the aforementioned film revealed diffraction peaks at (110), (200), (211), (111), and (220) in addition to the peak originating from the Si substrate. Therefore, the film produced in this example contained a mixture of Mo metallic phase and Mo nitride phase.

[0043] [Reference example 3] The procedure was carried out in the same manner as in Example 1, except that the heating temperature of the Si substrate was changed to 1058°C. As a result, a film was formed on the Si substrate. X-ray diffraction (XRD) of the aforementioned film revealed diffraction peaks at (110), (200), and (211) in addition to the peak originating from the Si substrate. These are characteristic diffraction peaks that appear in the Mo metallic phase. In other words, the film consisted solely of the Mo metallic phase.

[0044] The results are summarized in Table 1. Table-1 Heating temperature (℃) Generation phase Example 1: 578 c-Mo2N Example 2: 774 c-Mo2N Example 3: 895 c-Mo2N Example 4 932 c-Mo2N Reference example 1 937 c-Mo2N+Mometal Reference example 2 958 c-Mo2N+Mometal Reference Example 3 1058 Mometal

[0045] [Example 5] 100 sccm of NH3 was supplied into the deposition chamber (reactor), and the pressure inside the chamber was adjusted to 400 Pa. The Si substrate placed inside the deposition chamber was heated to 419°C by a semiconductor laser. After this, a precursor ((tBuN)2Mo(OtAm)2) was supplied into the deposition chamber (reactor) (50 sccm), and the pressure inside the chamber was adjusted to 800 Pa. The precursor was heated to 50°C. The precursor was supplied by bubbling N2 gas. As a result, a film was formed on the Si substrate. According to X-ray diffraction (XRD), the aforementioned film was a highly crystalline Mo metal nitride film. The XRD diffraction pattern is shown in Figure 5. In addition to the peaks originating from the Si substrate, diffraction peaks at (111), (200), and (220) were observed. These are characteristic diffraction peaks that appear in the c-Mo2N phase. Therefore, it is composed solely of the Mo nitride phase. In other words, the film was a single highly crystalline Mo metal nitride film (c-Mo2N).

[0046] [Example 6] The procedure was carried out in the same manner as in Example 5, except that the heating temperature of the Si substrate was changed to 497°C. As a result, a film was formed on the Si substrate. According to X-ray diffraction (XRD), the aforementioned film was a highly crystalline Mo metal nitride film. In addition to the peaks originating from the Si substrate, diffraction peaks at (111), (200), and (220) were observed. These are characteristic diffraction peaks that appear in the c-Mo2N phase. Therefore, it is composed solely of the Mo nitride phase. In other words, the film was a single highly crystalline Mo metal nitride film (c-Mo2N).

[0047] [Example 7] The procedure was carried out similarly to that in Example 5, except that the heating temperature of the Si substrate was changed to 844°C. As a result, a film was formed on the Si substrate. According to X-ray diffraction (XRD), the aforementioned film was a highly crystalline Mo metal nitride film. The XRD diffraction pattern is shown in Figure 6. In addition to the peaks originating from the Si substrate, diffraction peaks at (111), (200), and (220) were observed. These are characteristic diffraction peaks that appear in the c-Mo2N phase. Therefore, it is composed solely of the Mo nitride phase. In other words, the film was a single highly crystalline Mo metal nitride film (c-Mo2N).

[0048] [Example 8] The procedure was carried out in the same manner as in Example 5, except that the heating temperature of the Si substrate was changed to 926°C. As a result, a film was formed on the Si substrate. According to X-ray diffraction (XRD), the aforementioned film was a highly crystalline Mo metal nitride film. The XRD diffraction pattern is shown in Figure 7. In addition to the peaks originating from the Si substrate, diffraction peaks at (111), (200), and (220) were observed. These are characteristic diffraction peaks that appear in the c-Mo2N phase. Therefore, it is composed solely of the Mo nitride phase. In other words, the film was a single highly crystalline Mo metal nitride film (c-Mo2N).

[0049] [Reference example 4] The procedure was carried out in the same manner as in Example 5, except that the heating temperature of the Si substrate was changed to 1061°C. As a result, a film was formed on the Si substrate. X-ray diffraction (XRD) of the aforementioned film revealed diffraction peaks (110), (200), (211), (111), and (220) in addition to the peak originating from the Si substrate. The (110), (200), and (211) peaks are characteristic diffraction peaks that appear in the Mo metallic phase. The (111), (200), and (220) diffraction peaks are characteristic diffraction peaks that appear in the c-Mo2N phase. Therefore, the film produced in this example contained a mixture of Mo metallic phase and Mo nitride phase.

[0050] The results are summarized in Table 2. Table-2 Heating temperature (℃) Generation phase Example 5 419 c-Mo2N Example 6 497 c-Mo2N Example 7 844 c-Mo2N Example 8 926 c-Mo2N Reference example 4 1061 c-Mo2N+Mometal

[0051] From Tables 1 and 2 above, it can be seen that as the film deposition temperature increases, the phase changes from c-Mo2N to Mometal. This was something that no one could have predicted. It was discovered for the first time through this invention. Generally, materials containing self-oxidation sources (e.g., metal alkoxide compounds) can be expected to predominantly form oxygen-containing films (e.g., oxide films, oxynitride films). Nevertheless, in this invention, a single nitride film with excellent crystallinity was formed. This indicates that a deposition technique using a CVD process that utilizes an organic Mo material containing oxygen in its molecule as a precursor and NH3 as a reactant (substantially excluding H2) may be a better option for depositing a single Mo nitride film. [Reference example 5] Ar was supplied (100 sccm) into the deposition chamber (reactor), and the pressure inside the deposition chamber was adjusted to 400 Pa. The Si substrate placed inside the deposition chamber was heated to 494°C by a semiconductor laser. After this, the precursor ((tBuN)2Mo(OtAm)2) was supplied (50 sccm) into the deposition chamber (reactor), and the pressure inside the deposition chamber was adjusted to 800 Pa. The precursor was heated to 50°C. The precursor was supplied by bubbling N2 gas. As a result, a film was formed on the Si substrate. Films deposited without supplying NH3 were found to be single-phase MoO2 films according to X-ray diffraction (XRD).

[0052] [Reference example 6] The procedure was carried out similarly to that in Reference Example 5, except that the heating temperature of the Si substrate was changed to 746°C. As a result, a film was formed on the Si substrate. According to X-ray diffraction (XRD), the aforementioned film was a multiphase MoO2 film.

[0053] [Reference example 7] The procedure was carried out similarly to that in Reference Example 5, except that the heating temperature of the Si substrate was changed to 935°C. As a result, a film was formed on the Si substrate. According to X-ray diffraction (XRD), the aforementioned film was a multiphase MoO2 film.

[0054] From the above reference example 5-7, it can be seen that when an organo-VI transition metal having O and N organic groups is used as a precursor, even if the film deposition temperature is maintained below 935°C, the film obtained in reference example 5-7, where ammonia was not used, is an oxide film. A nitride film was not obtained. That is, if the molecule contains both an autonitriding source and an autooxidizing source, it would be expected that a film containing nitrogen and oxygen (for example, an oxynitride film) would be predominantly formed. Nevertheless, in reference example 5-7, the obtained film was an oxide film. In other words, even if the precursor itself has an autonitriding source (imide group), if it also has an autooxidizing source (alkoxy group), autooxidation acts predominantly, and a crystalline oxide film is formed.

[0055] To illustrate the nature of the present invention, it will be understood that many further modifications, including details such as materials, processes, and components, described and shown herein can be made by those skilled in the art within the principles and scope of the present invention as expressed in the appended claims.

[0056] The present invention is not intended to be limited to the examples and / or embodiments described above.

Claims

1. A film deposition method for forming a VI transition metal nitride film on a substrate placed in a film deposition chamber, An organic transition metal of group VI is supplied into the aforementioned film deposition chamber. A nitride source compound different from the organo-VI transition metal is supplied into the film deposition chamber. On the substrate, which is maintained at a temperature of 936°C or lower, the VI transition metal nitride film is formed from the nitride source compound and the organic VI transition metal supplied into the film deposition chamber. Film formation method.

2. The temperature of the substrate is less than 935°C. The method for forming a film according to claim 1.

3. The temperature of the substrate is 300°C or higher. The method for forming a film according to claim 2.

4. The nitride source compound is supplied into the film deposition chamber before the organo-VI transition metal is supplied. A method for forming a film according to claim 1 or claim 3.

5. The nitride source compound is NR １ R ２ R ３ (R １ , R ２ , R ３ (A group selected from the group consisting of H and alkyl groups having 3 or fewer carbon atoms) The method for forming a film according to claim 1.

6. The pressure inside the film deposition chamber is 800 Pa or less. The method for forming a film according to claim 1.

7. In the aforementioned film deposition chamber, hydrogen is not substantially supplied. The method for forming a film according to claim 1.

8. CVD is used for film formation. The method for forming a film according to claim 1.

9. Laser CVD is used for film deposition. The method for forming a film according to claim 1.

10. The organic group of the aforementioned organo-VI transition metal has an oxygen atom. The method for forming a film according to claim 1.

11. The organic group of the aforementioned organo-VI transition metal has O and N. The method for forming a film according to claim 1.

12. The aforementioned organo-VI transition metal is (tBuN). ２ M (OtAm) ２ [M is either Mo or W.] The method for forming a film according to claim 11.

13. The organic Group VI transition metal is (tBuN) ２ M(O-iPr)(O-tAm) [M is Mo or W.] The method for forming a film according to claim 11.

14. The aforementioned organo-VI transition metal is (tBuN). ２ M (OR ２ ) ( OR ３ ) [M is Mo or W. R ２ , R ３ It is an alkyl group having 2 to 5 carbon atoms. The method for forming a film according to claim 11.

15. The aforementioned organo-VI transition metal is (R １ N) ２ M (OR ２ ) ( OR ３ )) [M is Mo or W. R １ , R ２ , R ３ It is an alkyl group having 2 to 5 carbon atoms. The method for forming a film according to claim 11.

16. The alkyl group is an alkyl group having a branched chain. A method for forming a film according to claim 14 or claim 15.

17. The deposited VI transition metal nitride film is a single-phase film. The method for forming a film according to claim 1.

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