Low-resistance TiN semiconductor film and preparation process thereof

Abstract

The invention provides a low-resistance TiN semiconductor film and a preparation process thereof.The preparation process comprises the steps that a titanium tetrachloride ethanol solution is added into a cellulose solution, the pH value is adjusted to be neutral after stirring, polyvinylpyrrolidone is added, stirring is conducted for 10-30 min, and then a precursor solution is obtained; dropwise adding the precursor solution on a quartz glass substrate for film coating, placing the quartz glass substrate at 70-85 DEG C for reaction for 10-20 hours after film coating, taking out the quartz glass substrate, and placing the quartz glass substrate at-10--2 DEG C for freeze thawing for 5-12 hours to obtain an intermediate substrate; and placing the intermediate substrate in a tubular furnace in an inert gas atmosphere, introducing ammonia gas, starting programmed heating to 900-1000 DEG C, keeping the temperature at 900-1000 DEG C for 1-2 hours, and cooling to obtain the TiN semiconductor film. According to the low-resistance TiN semiconductor film, growth of a titanium nitride crystal phase can be well controlled in the preparation process, so that the semiconductor film has excellent conductivity.

Description

Technical Field

[0001] The present application relates to the technical field of TiN semiconductor thin films, and in particular to a low-resistance TiN semiconductor thin film and a preparation process thereof. Background Art

[0002] Hard film materials are generally 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) film has high hardness, wear resistance and corrosion resistance, and is an ideal film material for the surface of cemented carbide tools and molds. Depositing TiN film on workpieces such as turning tools, milling cutters, drills, bearings, gears, and molding technology tools can increase the surface hardness of the workpiece, improve wear resistance, and significantly improve its service life and durability. TiN film has not only been used on workpieces such as tools and molds, but also has a wide range of uses in diffusion barriers, optical films, and decorative films in the semiconductor field. For example: TiN is used for optical films for solar energy absorption, diffusion barriers for integrated circuits, etc.

[0003] At present, there are two main methods for preparing thin films: physical vapor deposition and chemical vapor deposition. Physical vapor deposition is a technology that uses physical processes such as thermal evaporation or glow discharge, arc discharge, etc. under vacuum conditions to achieve material migration and deposit a thin film on the surface of the part substrate. Physical vapor deposition thin films mostly use sputtering coating, but the sputtering equipment is complex, requires a vacuum system and high-voltage equipment, and the deposition speed is slow and the cost is high. Chemical vapor deposition technology is a technology that uses gaseous precursor reactions to generate solid thin films through chemical reactions between atoms and molecules. Its equipment 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] The present application provides a low-resistance TiN semiconductor film and its preparation process, which are used to solve the technical problems in the prior art that the titanium nitride film has high resistivity and poor conductivity due to the difficulty in controlling the crystal phase growth of the titanium nitride film during the preparation process.

[0005] In a first aspect, the present application provides a process for preparing a low-resistance TiN semiconductor thin film, the preparation process comprising:

[0006] 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;

[0007] 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;

[0008] 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.

[0009] In an optional embodiment, the titanium tetrachloride ethanol solution is prepared by adding 10 to 20 mL of titanium tetrachloride to 120 to 200 mL of anhydrous 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 optional embodiment, the mass volume ratio of the polyvinyl pyrrolidone and the titanium tetrachloride ethanol solution is (0.5-1.2) g: (8-25) mL;

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

[0013] In an optional implementation manner, during the coating process, the rotation speed of the coating machine is 3000-4000 rpm;

[0014] The coating time is 12 to 22 seconds, and the coating times are 3 to 5 times.

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

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

[0017] In an optional embodiment, 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.

[0018] In an optional embodiment, 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.

[0019] In a second aspect, an embodiment of the present application provides a low-resistance TiN semiconductor film, which is prepared by any possible implementation method of the first aspect of the present application.

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

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

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

[0023] 2. In the present application, ammonia is used as a nitrogen source. By purging in a tubular furnace, the ratio of titanium and nitrogen elements can be well controlled, thereby improving the conductive properties of the titanium nitride film. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0025] Figure 1 A process flow for preparing a low-resistance TiN semiconductor film provided in the embodiment of the present application Figure 1 ;

[0026] Figure 2 A process flow for preparing a low-resistance TiN semiconductor film provided in the embodiment of the present application Figure 2 .

[0027] The above drawings have shown clear embodiments of the present application, which will be described in more detail later. These drawings and text descriptions are not intended to limit the scope 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

[0028] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The implementations described in the following exemplary embodiments do not represent all implementations consistent with the present application. Instead, 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-mentioned technical problems are described in detail below with specific embodiments. The following specific embodiments 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] Example 1

[0031] A process for preparing a low-resistance TiN semiconductor film, comprising:

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

[0033] S202, adding cellulose to urea and sodium hydroxide aqueous solution, stirring, placing at -20°C, taking out and stirring at room temperature, repeating this process 5 times; wherein the mass volume ratio of cellulose, urea, sodium hydroxide and deionized water is 2g:2.5g:6g:200mL.

[0034] S203, adding the titanium tetrachloride ethanol solution to the cellulose solution, stirring, then dropping dilute hydrochloric acid to adjust the pH value to neutral, adding polyvinyl pyrrolidone and stirring for 30 minutes 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 the polyvinyl pyrrolidone to the titanium tetrachloride ethanol solution is 1.2g:25mL.

[0035] S204, adding the precursor solution to the quartz glass substrate for coating, the speed of the coating machine is 4000 rpm, coating is performed 5 times, each coating time is 22 seconds, after coating, it is placed at 85°C for reaction for 20 hours, taken out and placed at -10°C for freeze-thaw for 12 hours, to obtain an intermediate substrate.

[0036] S205, placing the intermediate substrate in a tubular furnace with a helium gas atmosphere, introducing ammonia gas, and starting a temperature program to increase to 1000°C at 2°C / min, and keeping the temperature for 2 hours and then cooling to obtain a TiN semiconductor film.

[0037] Example 2

[0038] A process for preparing a low-resistance TiN semiconductor film, comprising:

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

[0040] S202, adding cellulose to urea and sodium hydroxide aqueous solution, stirring, placing at -15°C, taking out and stirring at room temperature, repeating this process 4 times to obtain a cellulose solution; wherein the mass volume ratio of cellulose, urea, sodium hydroxide and deionized water is 1.5g:1.2g:4g:130mL.

[0041] S203. Add the titanium tetrachloride ethanol solution to the cellulose solution, stir, then drop dilute hydrochloric acid to adjust the pH value to neutral, add polyvinyl pyrrolidone and stir for 20 minutes to obtain a precursor solution; wherein the volume ratio of the titanium tetrachloride ethanol solution to the cellulose solution is 1.2:0.55, and the mass volume ratio of the polyvinyl pyrrolidone to the titanium tetrachloride ethanol solution is 0.7g:18mL.

[0042] S204, adding the precursor solution to the quartz glass substrate for coating, the speed of the coating machine is 35000rpm, coating is performed 4 times, each coating time is 16s, after coating, it is placed at 75℃ for reaction for 15h, taken out and placed at -5℃ for freeze-thaw for 7h, to obtain an intermediate substrate.

[0043] S205, placing the intermediate substrate in a tubular furnace with a nitrogen atmosphere, introducing ammonia, and starting a temperature increase program at 3°C / min to 950°C, and keeping the temperature for 1 hour and then cooling to obtain a TiN semiconductor film.

[0044] Example 3

[0045] A process for preparing a low-resistance TiN semiconductor film, comprising:

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

[0047] S202, adding cellulose to urea and sodium hydroxide aqueous solution, stirring, placing at -10°C, taking out and stirring at room temperature, repeating this process 5 times; wherein the mass volume ratio of cellulose, urea, sodium hydroxide and deionized water is 1g:0.6g:2g:50mL.

[0048] S203, adding the titanium tetrachloride ethanol solution to the cellulose solution, stirring, then dropping dilute hydrochloric acid to adjust the pH value to neutral, adding polyvinyl pyrrolidone and stirring for 10 minutes to obtain a precursor solution; wherein the volume ratio of the titanium tetrachloride ethanol solution to the cellulose solution is 1:0.32, and the mass volume ratio of the polyvinyl pyrrolidone to the titanium tetrachloride ethanol solution is 0.5g:8mL.

[0049] S204, adding the precursor solution to the quartz glass substrate for coating, the speed of the coating machine is 3000 rpm, coating is performed 3 times, each coating time is 12 s, after coating, it is placed at 80°C for reaction for 16 hours, taken out and placed at -2°C for freeze-thaw for 5 hours, to obtain an intermediate substrate.

[0050] S205. Place the intermediate substrate in a tubular furnace with an argon gas atmosphere, introduce ammonia gas, and start a temperature increase program at 4°C / min to 900°C. Keep the temperature for 2 hours and then cool to obtain a TiN semiconductor film.

[0051] Comparative Example 1

[0052] The only difference between this comparative example and Example 1 is that this comparative example does not contain step S202, does not add cellulose solution in step S203, 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 that after the coating reaction is completed in step S204 of this comparative example, the low-temperature freeze-thaw method is not used, and step S205 is directly performed.

[0055] Comparative Example 3

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

[0057] Comparative Example 4

[0058] The TiN semiconductor film in this comparative example was prepared using patent document CN106746711A.

[0059] It is noted here that the preparation of the above-mentioned semiconductor thin films is carried out using preparation equipment and instruments well known to those skilled in the art, such as coating in a vacuum glove box, etc., which will not be described in detail here.

[0060] Performance Testing:

[0061] The resistivity of the titanium nitride semiconductor films in the above-mentioned Examples 1 to 3 and Comparative Examples 1 to 4 was tested using a test method commonly used in the art. The test results are shown in Table 1.

[0062] Table 1. Test results

[0063]

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

[0065] Unless otherwise indicated, the terms and phrases used herein have the meanings listed below. A particular term or phrase should not be considered to be indefinite or unclear unless otherwise defined, but should be interpreted according to the meaning generally understood by those skilled in the art. When a trade name appears in this article, it is intended to refer to the corresponding commercial product or its active ingredient.

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

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

[0068] The expression "comprising" or its synonymous similar expressions "including", "containing" and "having" etc. are open-ended and do not exclude additional unrecited elements, steps or ingredients. The expression "consisting of excludes any element, step or ingredient not specified. The expression "consisting essentially of means that the scope is limited to the specified elements, steps or ingredients, plus the optional elements, steps or ingredients that do not materially affect the basic and novel characteristics of the claimed subject matter. It should be understood that the expression "comprising" encompasses the expressions "consisting essentially of" and "consisting of".

[0069] The term "optional" or "optionally" means that the subsequently described event or circumstance may or may not occur, and that the description includes both occurring and not occurring of said event or circumstance.

[0070] The expression "one or more" or "at least one" may mean 1, 2, 3, 4, 5, 6, 7, 8, 9 or more.

[0071] The term "and / or" encompasses "and" and "or". Elements qualified by "and / or" include any one of them and any combination thereof. For example, A and / or B encompasses A, B, and A+B. A, B, and / or C encompasses A, B, C, A+B, A+C, B+C, and A+B+C.

[0072] Those skilled in the art will readily appreciate other embodiments of the present application after considering the specification and practicing the invention disclosed herein. The present application is intended to cover any modification, use or adaptation of the present application, which follows the general principles of the present application and includes common knowledge or customary techniques in the art that are not disclosed in the present application. The specification and examples are intended to be exemplary only, and the true scope and spirit of the present application are indicated by the following claims.

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

Claims

1. A process for preparing a low-resistance TiN semiconductor film, characterized in that: The preparation process comprises: Adding the titanium tetrachloride ethanol solution to the cellulose solution, adjusting the pH value to neutral after stirring, adding polyvinyl pyrrolidone and stirring 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. A 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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