A low-resistance TiN semiconductor thin film and its preparation process

Abstract

The present application provides a low-resistance TiN semiconductor thin film and a preparation process thereof, including: adding a titanium tetrachloride ethanol solution to a cellulose solution, adjusting the pH value to neutral after stirring, adding polyvinylpyrrolidone and stirring for 10 to 30 minutes to obtain a precursor solution; dropping the precursor solution onto a quartz glass substrate for film coating, placing it at 70 to 85 °C after film coating for reaction for 10 to 20 hours, taking it out and placing it at -10 to -2 °C for freeze-thawing for 5 to 12 hours to obtain an intermediate substrate; placing the intermediate substrate in a tubular furnace under an inert gas atmosphere, introducing ammonia gas, starting to increase the temperature programatically to 900 to 1000 °C, and maintaining the temperature at this temperature for 1 to 2 hours and then cooling to obtain a TiN semiconductor thin film. The low-resistance TiN semiconductor thin film of the present application can well control the growth of the titanium nitride crystal phase during the preparation process, so that the semiconductor thin film has excellent electrical conductivity.

Description

Technical Field

[0001] This application relates to the technical field of TiN semiconductor thin films, and particularly to a low-resistance TiN semiconductor thin film and its preparation process. Background Art

[0002] Hard film materials are generally film layers used to improve the wear resistance and corrosion resistance of the substrate surface, such as nitride, carbide, boride and other thin film materials. Titanium nitride (TiN) thin film has high hardness, wear resistance and corrosion resistance, and is an ideal thin film material for the surface of cemented carbide tools and dies. Depositing TiN thin film on workpieces such as turning tools, milling cutters, drills, bearings, gears, and forming technology tools can improve the surface hardness of the workpieces, improve the wear resistance, and significantly improve their service life and durability. TiN thin film has not only been applied to workpieces such as tools and dies, but also has a wide range of uses in aspects such as diffusion barriers, optical films, and decorative films in the semiconductor field. For example: TiN is used in optical films for solar energy absorption, diffusion barriers of integrated circuits, etc.

[0003] At present, the preparation methods of thin films mainly include physical vapor deposition and chemical vapor deposition. Physical vapor deposition is a technology that, under vacuum conditions, uses physical processes such as thermal evaporation, glow discharge, and arc discharge to achieve the migration of materials and deposit a thin film on the surface of the part substrate. Sputtering coating is mostly used for physical vapor deposition thin films, but it has the disadvantages of complex sputtering equipment, the need for a vacuum system and a high-voltage device, slow deposition speed, and high cost. Chemical vapor deposition technology is a technology that uses gaseous precursor reactions to generate solid thin films through the chemical reaction pathway between atoms and molecules. Its device mainly includes gas generation, purification, mixing and transportation devices, reaction chambers, substrate heating devices, and exhaust devices. The equipment is complex, the process control is difficult, the repeatability is poor, and the operation is difficult. Summary of the Invention

[0004] This application provides a low-resistance TiN semiconductor thin film and its preparation process to solve the technical problems in the prior art that in the preparation process of titanium nitride thin film, the crystal phase growth of titanium nitride thin film is not easy to control, and thus the resistivity of the titanium nitride semiconductor thin film is relatively high and the electrical conductivity is poor.

[0005] In a first aspect, this application provides a preparation process of a low-resistance TiN semiconductor thin film, and the preparation process includes:

[0006] Adding a titanium tetrachloride ethanol solution to a cellulose solution, adjusting the pH value to neutral after stirring, and adding polyvinylpyrrolidone and stirring for 10 - 30 minutes to obtain a precursor solution;

[0007] Drop the precursor solution onto a quartz glass substrate for film coating. After film coating, place it at 70 - 85 °C for reaction for 10 - 20 h, take it out and place it at -10 - -2 °C for freeze-thaw for 5 - 12 h to obtain an intermediate substrate;

[0008] Place the intermediate substrate in a tubular furnace under an inert gas atmosphere, introduce ammonia gas, start programmed heating to 900 - 1000 °C, and keep it at this temperature for 1 - 2 h and then cool down to obtain a TiN semiconductor thin film.

[0009] In an alternative embodiment, the titanium tetrachloride ethanol solution is prepared by adding 10 - 20 mL of titanium tetrachloride to 120 - 200 mL of absolute ethanol;

[0010] The volume ratio of the titanium tetrachloride ethanol solution to the cellulose solution is (1 - 2):(0.32 - 0.86).

[0011] In an alternative embodiment, the mass-volume ratio of polyvinylpyrrolidone to the titanium tetrachloride ethanol solution is (0.5 - 1.2) g:(8 - 25) mL;

[0012] The pH value is adjusted by dropping dilute hydrochloric acid.

[0013] In an alternative embodiment, during the film coating process, the rotation speed of the spin coater is 3000 - 4000 rpm;

[0014] The film coating time is 12 - 22 s, and the number of film coating times is 3 - 5 times.

[0015] In an alternative embodiment, the inert gas is any one of nitrogen, argon, and helium.

[0016] In an alternative embodiment, the heating rate of the programmed heating is 2 - 4 °C / min.

[0017] In an alternative embodiment, the cellulose solution is obtained by adding cellulose to an aqueous solution of urea and sodium hydroxide, stirring, placing it at -20 - -10 °C, taking it out and stirring at room temperature, and repeating this process 3 - 5 times.

[0018] In an alternative embodiment, the mass-volume ratio of cellulose, urea, sodium hydroxide, and deionized water is (1 - 2) g:(0.6 - 2.5) g:(2 - 6) g:(50 - 200) mL.

[0019] In a second aspect, the embodiments of the present application provide a low-resistance TiN semiconductor thin film, and the TiN semiconductor thin film is prepared by any one of the possible embodiments in the first aspect of the present application.

[0020] In a third aspect, the present application provides a semiconductor device, which includes a TiN semiconductor thin film prepared by the preparation process of any one of the embodiments in the first aspect, and / or a TiN semiconductor thin film provided in the second aspect.

[0021] The low-resistance TiN semiconductor thin film and its preparation process provided by the present application further have the following beneficial effects compared with the prior art:

[0022] 1. In the present application, a mixed solution of a cellulose solution and a titanium tetrachloride solution is used as a titanium source. During the preparation process, after film coating and gelation reaction, it is placed in a low-temperature environment for freeze-thawing. By utilizing the fact that cellulose can control the growth direction of fiber crystals during the freeze-thawing process in a low-temperature environment, the growth of the titanium nitride crystal phase can be controlled, to a certain extent, the crystal phase of titanium nitride can be controlled, thereby reducing the resistivity of the semiconductor thin film and improving its electrical conductivity.

[0023] 2. In the present application, ammonia gas is used as a nitrogen source. By means of purging in a tube furnace, the ratio of titanium and nitrogen elements can be well controlled, so as to improve the electrical conductivity of the titanium nitride thin film. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The accompanying drawings herein are incorporated into the specification and form a part of the specification, showing embodiments consistent with the present application, and are used together with the specification to explain the principles of the present application.

[0025] Figure 1 is the preparation process flow of a low-resistance TiN semiconductor thin film provided by an embodiment of the present application Figure 1 ;

[0026] Figure 2 is the preparation process flow of a low-resistance TiN semiconductor thin film provided by an embodiment of the present application Figure 2 .

[0027] Through the above accompanying drawings, the clear embodiments of the present application have been shown, and there will be more detailed descriptions hereinafter. These drawings and textual descriptions are not intended to limit the scope of the concept of the present application in any way, but to illustrate the concept of the present application to those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0028] Here, the exemplary embodiments will be described in detail, and the examples are shown in the accompanying drawings. When the following description refers to the accompanying drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present application. On the contrary, they are merely examples of devices and methods consistent with some aspects of the present application as detailed in the appended claims.

[0029] The technical solution of the present application and how the technical solution of the present application solves the above technical problems will be described in detail below with specific embodiments. These several specific embodiments below can be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments. The embodiments of the present application will be described below in conjunction with the accompanying drawings.

[0030] Embodiment 1

[0031] A preparation process of a low-resistance TiN semiconductor thin film includes:

[0032] S201. Add 20 mL of titanium tetrachloride to 200 mL of absolute ethanol to obtain a titanium tetrachloride ethanol solution.

[0033] S202. Add cellulose to a urea and sodium hydroxide aqueous solution, stir, place it at -20 °C, take it out and stir at room temperature, and repeat this process 5 times to obtain; wherein, the mass-volume ratio of cellulose, urea, sodium hydroxide and deionized water is 2 g: 2.5 g: 6 g: 200 mL.

[0034] S203. Add the titanium tetrachloride ethanol solution to the cellulose solution, stir, then add dilute hydrochloric acid to adjust the pH value to neutral, add polyvinylpyrrolidone and stir for 30 min to obtain a precursor solution; wherein, the volume ratio of the titanium tetrachloride ethanol solution to the cellulose solution is 2:0.86, and the mass-volume ratio of polyvinylpyrrolidone to the titanium tetrachloride ethanol solution is 1.2 g: 25 mL.

[0035] S204. Drop the precursor solution on a quartz glass substrate for film coating. The rotation speed of the spin coater is 4000 rpm, and the film is coated 5 times, with each coating for 22 s. After coating, place it at 85 °C for reaction for 20 h, take it out and place it at -10 °C for freeze-thaw for 12 h to obtain an intermediate substrate.

[0036] S205. Place the intermediate substrate in a tubular furnace with a helium gas atmosphere, introduce ammonia gas, start to program the temperature increase at 2 °C / min to 1000 °C, and keep it at this temperature for 2 h and then cool it to obtain a TiN semiconductor thin film.

[0037] Embodiment 2

[0038] A preparation process of a low-resistance TiN semiconductor thin film includes:

[0039] S201. Add 15 mL of titanium tetrachloride to 160 mL of absolute ethanol to obtain a titanium tetrachloride ethanol solution.

[0040] S202. Add cellulose to an aqueous solution of urea and sodium hydroxide, stir, place it at -15°C, take it out and stir at room temperature, and repeat this process 4 times to obtain a cellulose solution. Among them, the mass-volume ratio of cellulose, urea, sodium hydroxide, and deionized water is 1.5 g: 1.2 g: 4 g: 130 mL.

[0041] S203. Add the titanium tetrachloride ethanol solution to the cellulose solution, stir, then add dilute hydrochloric acid to adjust the pH value to neutral, add polyvinylpyrrolidone and stir for 20 min to obtain a precursor solution. Among them, the volume ratio of the titanium tetrachloride ethanol solution to the cellulose solution is 1.2:0.55, and the mass-volume ratio of polyvinylpyrrolidone to the titanium tetrachloride ethanol solution is 0.7 g: 18 mL.

[0042] S204. Drop the precursor solution on a quartz glass substrate for coating. The rotation speed of the spin coater is 35000 rpm, coat 4 times, each coating for 16 s. After coating, place it at 75°C for reaction for 15 h, take it out and place it at -5°C for freeze-thaw for 7 h to obtain an intermediate substrate.

[0043] S205. Place the intermediate substrate in a tubular furnace under a nitrogen gas atmosphere, introduce ammonia gas, start to program the temperature increase at 3°C / min to 950°C, and keep it at this temperature for 1 h and then cool down to obtain a TiN semiconductor thin film.

[0044] Example 3

[0045] A preparation process of a low-resistance TiN semiconductor thin film, including:

[0046] S201. Add 10 mL of titanium tetrachloride to 140 mL of absolute ethanol to obtain a titanium tetrachloride ethanol solution.

[0047] S202. Add cellulose to an aqueous solution of urea and sodium hydroxide, stir, place it at -10°C, take it out and stir at room temperature, and repeat this process 5 times to obtain; among them, the mass-volume ratio of cellulose, urea, sodium hydroxide, and deionized water is 1 g: 0.6 g: 2 g: 50 mL.

[0048] S203. Add the titanium tetrachloride ethanol solution to the cellulose solution, stir, then add dilute hydrochloric acid to adjust the pH value to neutral, add polyvinylpyrrolidone and stir for 10 min to obtain a precursor solution. Among them, the volume ratio of the titanium tetrachloride ethanol solution to the cellulose solution is 1:0.32, and the mass-volume ratio of polyvinylpyrrolidone to the titanium tetrachloride ethanol solution is 0.5 g: 8 mL.

[0049] S204. Drop the precursor solution onto the quartz glass substrate for film coating. The rotation speed of the spin coater is 3000 rpm. Coat the film 3 times, with each coating lasting 12 s. After coating, place it at 80 °C for reaction for 16 h, then take it out and place it at -2 °C for freeze-thaw for 5 h to obtain the intermediate substrate.

[0050] S205. Place the intermediate substrate in a tube furnace under an argon gas atmosphere, introduce ammonia gas, start the programmed temperature increase from 4 °C / min to 900 °C, and keep it at this temperature for 2 h and then cool it to obtain the TiN semiconductor thin film.

[0051] Comparative Example 1

[0052] The difference between this comparative example and Example 1 is only that this comparative example does not contain the S202 step, does not add the cellulose solution in the S203 step, and does not use dilute hydrochloric acid to adjust the pH value.

[0053] Comparative Example 2

[0054] The difference between this comparative example and Example 1 is only that after the film coating reaction in the S204 step of this comparative example, the low-temperature freeze-thaw method is not used, and the S205 step is directly carried out.

[0055] Comparative Example 3

[0056] The TiN semiconductor thin film in this comparative example is prepared by using the patent document CN110965023A.

[0057] Comparative Example 4

[0058] The TiN semiconductor thin film in this comparative example is prepared by using the patent document CN106746711A.

[0059] It should be noted here that the above preparation of the semiconductor thin film is carried out by using the well-known preparation equipment and instruments by those skilled in the art. For example, the film coating is carried out in a vacuum glove box, etc., and will not be elaborated in detail here.

[0060] Performance test:

[0061] For the titanium nitride semiconductor thin films in the above Examples 1 to 3 and Comparative Examples 1 to 4, the resistivity is tested by using the general test methods in the art, and the test results are shown in Table 1.

[0062] Table 1. Test results

[0063]

[0064] As can be seen from Table 1, compared with the semiconductor films in Comparative Examples 1 to 4, the TiN semiconductor thin films in Examples 1 to 3 have more excellent conductivity.

[0065] Unless otherwise indicated, the terms and phrases used herein have the meanings set forth below. A particular term or phrase should not be considered indefinite or unclear merely because it is not specifically defined, but should be construed in accordance with the meaning that would be commonly understood by one of ordinary skill in the art. When a trade name appears in this document, it is intended to refer to the corresponding good or its active ingredient.

[0066] Unless otherwise specifically defined or reasonably determinable from the context, ratios (including percentages) or parts used herein are by weight.

[0067] The terms “about” or “approximately,” when used in conjunction with a numerical variable, generally refer to the value of that variable and all values of that variable within experimental error (e.g., within a 95% confidence interval for an average value) or within ±10% of the specified value, or a wider range.

[0068] The recitation “comprising” or similar recitations such as “including,” “containing,” and “having” are open-ended and do not exclude additional unrecited elements, steps, or components. The recitation “consisting of” excludes any unstated element, step, or component. The recitation “consisting essentially of” limits the scope to the specified elements, steps, or components, plus optionally present elements, steps, or components that do not materially affect the basic and novel characteristics of the claimed subject matter. It should be understood that the recitation “comprising” encompasses the recitations “consisting essentially of” and “consisting of.”

[0069] The term “optionally” or “optionally” means that the subsequent described event or circumstance may or may not occur, and the description includes both the occurrence and non-occurrence of the described event or circumstance.

[0070] The recitation “one or more” or “at least one” can mean 1, 2, 3, 4, 5, 6, 7, 8, 9, or more.

[0071] The term “and / or” encompasses both “and” and “or.” Elements qualified by “and / or” mean that any one of them and any combination thereof are covered. For example, A and / or B covers A, B, and A + B. A, B, and / or C covers A, B, C, A + B, A + C, B + C, and A + B + C.

[0072] After considering the specification and practicing the invention disclosed herein, other embodiments of the present application will readily occur to those of ordinary skill in the art. The present application is intended to cover any variations, uses, or adaptations of the present application that follow the general principles of the present application and include well-known knowledge or conventional technical means in the technical field not disclosed in the present application. The specification and examples are only to be considered exemplary, and the true scope and spirit of the present application are pointed out by the following claims.

[0073] It should be understood that the present application is not limited to the exact structures described above and shown in the drawings, and various modifications and changes can be made without departing from its scope. The scope of the present application is only limited by the appended claims.

Claims

1. A process for preparing a low-resistance TiN semiconductor film, characterized in that: The preparation process comprises: The titanium tetrachloride ethanol solution is added to the cellulose solution, and the pH value is adjusted to neutral after stirring, and polyvinyl pyrrolidone is added and stirred for 10 to 30 minutes to obtain a precursor solution; The precursor solution is added dropwise onto a quartz glass substrate for coating, and after coating, the substrate is placed at 70 to 85° C. for reaction for 10 to 20 hours, and then taken out and placed at -10 to -2° C. for freeze-thawing for 5 to 12 hours to obtain an intermediate substrate; The intermediate substrate is placed in a tubular furnace with an inert gas atmosphere, ammonia is introduced, and the temperature is raised to 900-1000° C., and the temperature is kept at this temperature for 1-2 hours and then cooled to obtain a TiN semiconductor film.

2. The process for preparing a low-resistance TiN semiconductor thin film according to claim 1, characterized in that: The titanium tetrachloride ethanol solution is prepared by adding 10 to 20 mL of titanium tetrachloride to 120 to 200 mL of anhydrous ethanol; The volume ratio of the titanium tetrachloride ethanol solution to the cellulose solution is (1-2):(0.32-0.86).

3. The process for preparing a low-resistance TiN semiconductor thin film according to claim 1, characterized in that: The mass volume ratio of the polyvinyl pyrrolidone and the titanium tetrachloride ethanol solution is (0.5-1.2) g: (8-25) mL; The pH value is adjusted by adding dilute hydrochloric acid.

4. The process for preparing a low-resistance TiN semiconductor thin film according to claim 1, characterized in that: During the coating process, the rotation speed of the coating machine is 3000-4000 rpm; The coating time is 12 to 22 seconds, and the coating times are 3 to 5 times.

5. The process for preparing a low-resistance TiN semiconductor thin film according to claim 1, characterized in that: The inert gas is any one of nitrogen, argon and helium.

6. The process for preparing a low-resistance TiN semiconductor thin film according to claim 1, characterized in that: The heating rate of the programmed temperature increase is 2-4°C / min.

7. The process for preparing a low-resistance TiN semiconductor thin film according to claim 1, characterized in that: The cellulose solution is obtained by adding cellulose to urea and sodium hydroxide aqueous solution, stirring, placing at -20 to -10°C, taking out and stirring at room temperature, and repeating this process 3 to 5 times.

8. The process for preparing a low-resistance TiN semiconductor thin film according to claim 7, characterized in that: The mass volume ratio of the cellulose, urea, sodium hydroxide and deionized water is (1-2) g: (0.6-2.5) g: (2-6) g: (50-200) mL.

9. A low-resistance TiN semiconductor film, characterized in that: The semiconductor thin film is prepared by the preparation process described in any one of claims 1 to 8.

10. A semiconductor device, characterized in that: The semiconductor device comprises a TiN semiconductor thin film obtained by any one of the preparation processes of claims 1 to 8, and / or a TiN semiconductor thin film according to claim 9.

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