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Article

Effect of Sputtering Process Parameters on Physical Properties and Electron Emission Level of Titanium Nitride Films

by
Yang Xia
1 and
Dan Wang
2,*
1
School of Intelligent Manufacturing, Chongqing Technology and Businesses Institute, Chongqing 401520, China
2
School of Microelectronics, Xi’an Jiaotong University, Xi’an 710049, China
*
Author to whom correspondence should be addressed.
Inorganics 2025, 13(6), 201; https://doi.org/10.3390/inorganics13060201
Submission received: 11 May 2025 / Revised: 5 June 2025 / Accepted: 8 June 2025 / Published: 16 June 2025
(This article belongs to the Special Issue Novel Inorganic Coatings and Thin Films)
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Abstract

:
Titanium nitride (TiN) is a typical inorganic compound capable of achieving resistance modulation by adjusting the element ratio. In this work, to deeply investigate the resistance-tunable characteristics and electron emission properties of TiN, we prepared 10 sets of TiN films by adjusting the magnetron sputtering parameters. The microscopic analyses show that the film thicknesses ranged from about 355 to 459 nm. Moreover, with the process parameters used in this work, TiN nanostructures are formed more easily when the nitrogen flow rate is ≤5 sccm, and compact TiN films are formed more easily when the nitrogen flow rate is ≥10 sccm. Elemental analyses showed that the N:Ti atomic ratios of the TiN films ranged from about 0.587 to 1.40. The results of surface analysis showed the presence of a certain amount of oxygen on the surface of the TiN film, indicating that the surface TiN may exist in the form of TiN:O. The electrical resistance test showed that the resistivity of the TiN coating ranges from 1.59 × 10−4 to 1.83 × 10−1 Ω·m. And the closer the N:Ti atomic ratio is to one, the lower the TiN film resistivity is. The electron emission coefficient (EEC) results show that among the film samples from #3 to #10, sample #8 has the lowest EEC, with a peak EEC of only 1.61. By comparing the resistivity and EEC data, a novel phenomenon was discovered: a decrease in the resistivity of TiN films leads to a decrease in their EEC values. The results show that the resistivity and EEC of TiN films can be adjusted according to the film-forming components, which is important for the application of TiN in the electronics industry.

1. Introduction

Titanium nitride (TiN) is a typical inorganic compound material with special conductivity characteristics, and it has been widely employed in space science, electron components, and biomedicine on account of its excellent physical and chemical properties, and extreme biocompatibility [1,2,3,4]. The excellent physical and chemical properties of TiN include outstanding hardness and strength, remarkable ability of corrosion resistance, good stability at high temperature, and a low electron emission coefficient [5,6,7,8,9]. In the industry of vacuum coating, TiN is extensively used as the passivation layer on the surface of various materials, which can greatly improve the oxidation resistance without affecting the electrical properties of the material [2,5]. In addition, TiN ceramic can be utilized as a decorating film on the surface of mechanical tools to enhance their abrasion resistance due to its high rigidity [8]. In terms of space science, TiN is usually deposited on the surface of spacecraft components as a protective coating to lower the effect of secondary electron emission [9,10,11,12].
In the past few decades, many deposition techniques have been developed to prepare TiN films. Mainstream physical vapor deposition methods [13,14,15,16,17,18,19,20,21] include magnetron sputtering, ion implantation [14,15], thermal spraying [16,17], and pulsed laser deposition [18,19,20,21]. Plasma-assisted chemical vapor deposition [22] and direct current [23] or RF reactive sputtering [1,3] are the main chemical vapor deposition techniques [1,16,17,18,19,20,21,22,23,24] to fabricate TiN films. Typical studies in this area include some of the examples below. In 1998, the work of Xiao et al. showed that TiN films fabricated by RF sputtering were more likely to be highly oriented in TiN <200> [25]. Also in 1998, Schmid et al. analyzed the optical and electronic properties of sputtered TiNx films with microcosmic calculation [26]. In 2015, Merie used the DC reactive magnetron sputtering technique to prepare the TiN films, exhibiting that roughness varied between 0.413 nm and 1.375 nm when the substrate temperature ranges from room temperature (RT) to 500 °C [23]. In 2024–2025, scholars from India conducted detailed studies on the physical properties of sputtered TiN, including the crystalline quality of TiN films, surface states, elemental components, etc. [27,28]. They utilized various surface microanalysis techniques to determine the optical properties and negative dielectric properties of TiN thin films prepared with different N:Ti atomic ratios, and discussed the application of TiN films in the field of plasma. In addition, the application of TiN films in the field of vacuum electron emission has received much attention. From the 1990s to the 2000s, Michizono et al. systematically investigated the practical value of TiN functional films for reliability enhancement of alumina dielectric windows, demonstrating that TiN coatings on sensitive surfaces can substantially moderate surface charging, flashover, and secondary electron avalanche problems on dielectric window surfaces [10,29,30,31]. In 2007, Ruiz et al. investigated the effect of storage time on the surface state and electron emissivity of TiN films. This study revealed the physical mechanism by which the surface state of TiN films changes with storage time and gave the evolution of the surface electron emissivity, demonstrating that the surface electron emissivity of TiN films tends to stabilize after two months of storage [11]. Also in 2007, Montero et al. reported a TiN film with low electron emissivity, which they assumed to be in the form of TiN:O since compositional analyses showed a certain amount of O inside the film. In the study, they achieved an electron emission coefficient (EEC) of less than 0.97 for TiN:O films by a process of Ar+ cleaning, carbon injection, and high-temperature annealing treatment [32]. In summary, the physical properties of TiN films are crucial for their corresponding multiple application scenarios.
However, there have been few reports on the relationship between the electron emission characteristics of TiN and its physical properties. In this work, to deeply study the physical properties and electron emission characteristics of TiN surfaces, we prepared TiN films using RF reactive magnetron sputtering with various process parameters. The effects of parameters, including gas flow rate, sputtering power, and sputtering pressure, on the physical properties of TiN films were systematically studied. In order to study the effect of TiN film composition on film resistivity, the regularity of electrical resistivity variation versus the atomic ratio of N:Ti was established. Moreover, the EEC of the TiN film surface was characterized, and the relationship between the EEC characteristics and other physical properties of the TiN film was analyzed in detail.

2. Results and Discussion

2.1. Morphology Characterization of TiN Films

Figure 1 shows the surface morphology photos and cross-section images of typical TiN samples #1–#4 with the same magnification. The scanning electron microscope (SEM) characterization results in Figure 1 show that the TiN films formed by magnetron sputtering could be either in the form of loose nanostructures or in the form of compact films. Specifically, in the process used in this study, it is easier to form loose TiN nanostructures when the N2 flow rate is relatively low (≤5 sccm), which can be summarized in Figure 1a,b,e,f. Figure 1a,b show that the nanoparticle size on the top of the prepared TiN nanostructure surface is about tens of nanometers. On the contrary, in the process used in this study, it is easier to form compact TiN films when the N2 flow rate is relatively high (≥10 sccm), and this conclusion can be summarized from Figure 1c,d,g,h. In Figure 1c,d,g,h, we see that the surfaces of these TiN films seem to be pretty flat and smooth. Comparing the process parameters of Figure 1a–c, it seems that the loosened TiN nanostructure is more likely to be prepared when the N2 flow rate is small. This kind of phenomenon may prove that introducing a certain flow rate of N2 may greatly transform the growth orientation and crystallization property of the TiN crystal.
The sample thickness data can be obtained by observing cross-section images in Figure 1. Here, we obtained the statistics for the film thickness information; the specific values of film thickness of TiN films #1–#10 are listed in Table 1. To avoid testing errors caused by random factors, we selected five sections for thickness testing, and the results shown in Table 1 are the average of the five reasonable test values, where the error is less than ±10 nm. Moreover, in Table 1, according to the sputtering duration of 180 min, the depositing velocity was calculated. Figure 2 shows the variation tendency of the depositing velocity with process parameters, including the gas flow rate of N2:Ar, sputtering power, and sputtering pressure, changing. It is shown in Figure 2a that a big gas flow rate of N2:Ar results in a remarkable decrease in the depositing velocity. This is attributed to that a reduction in the working gas ratio will lead to a reduction in the Ar ion concentration, and the amount of Ar+ that impacts the target decreases, so the number of atoms sputtered from the target decreases as well, resulting in a lower depositing velocity. Figure 2b demonstrates that the depositing velocity can be efficiently improved by increasing sputtering power. This is because an improvement in sputtering power may result in an enhancement of impact energy; as a result, more target atoms are sputtered from the sputtering source, and so the depositing velocity goes higher. However, overhigh sputtering power may result in overhigh impacting energy and temperature, which may damage the sputtering source. Figure 2c indicates that there is no significant change in the depositing velocity when the sputtering pressure changes from 0.8 Pa to 2.0 Pa; merely, 1.2 Pa seems to be more appropriate for improving the depositing velocity in this experiment.

2.2. Composition Characterization of TiN Films

TiNx is a kind of non-stoichiometric compound [33], and it is possible to form a crystal structure when “x” ranges from 0.37 to 1.63 [34,35]. Therefore, the atomic ratio of the N and Ti elements is not certain with different depositing parameters being applied. In this work, the elemental content of all TiN films was measured by the technology of energy dispersive spectroscopy (EDS). During testing, five sampling points were selected for EDS testing. The final results were calculated as the average of the five representative test points, with three significant digits, and a testing error of less than ±6%. The final test atomic ratio data of N:Ti are displayed in Table 1. Three groups of comparable test data of samples #1~#10 were pictured in Figure 3. It is demonstrated in Figure 3a that the content of the N element inside the TiN film can be significantly enhanced by increasing the proportion of N2 when introducing sputtering gas. This is attributed to that when there is a small amount of N2, the gas ratio of working gas Ar is high, so more target atoms may be sputtered when the Ar ions impact the target, and a chemical reaction will be set off if a small amount of reactive gas N2 is introduced at this time. However, when more reactive gas N2 is introduced, the gas ratio of working gas Ar will decrease, which may observably decrease the sputtering velocity, and the chemical reaction becomes weak at the same time. From Figure 3b, we can conclude that there is no significant variation in N content when the sputtering power goes higher, indicating that although higher sputtering power results in higher sputtering velocity, chemical reactions during sputtering are barely influenced. Similarly, Figure 3c reveals that sputtering gas pressure has little impact on the film composition; however, it seems that with a 1.2 Pa sputtering pressure, it may be more appropriate to prepare TiN films with a high amount of N.
As it is known to us that the detection depth of EDS is about several micrometers (usually several micrometers); therefore, EDS is more representative of characterizing the elemental content of a thick film or a bulk. Here, to further investigate the elemental composition of the TiN film, especially the surface condition, we employed X-ray photoelectron spectroscopy (XPS) to confirm the surface elemental content of C, N, O, and Ti, respectively. As we all know, the detection depth of XPS is about several nanometers; therefore, XPS is very sensitive to surface oxidation and contamination. Before the XPS measurement, the samples were cleaned in an ultrasonic bath with acetone, alcohol, and ultrapure water in turn to eliminate the contamination as much as possible. The XPS results of sample #3 are depicted in Figure 4. From Figure 4, we see that there exists some inevitable C and O on the TiN film surface, and this phenomenon means that the film surfaces were partly oxidized or contaminated before the XPS test. In addition, some other researchers have also investigated the O content inside the TiN coatings, and they verified that the low content of O may exist inside the TiN coating under a high vacuum condition [32]. In addition, the presence of element C indicates that a small amount of organic contamination was produced on the sample surface prior to the XPS test, which is unavoidable when the sample is exposed to atmospheric conditions. Figure 4b shows the fine XPS spectra of Ti 2p for sample #3; the dividing results of Ti 2p indicate that the fabricated sample #3 is a kind of mixture that is formed by TiON and TiN.

2.3. Characterization of Electrical Resistivity Property for the TiN Films

Electrical resistivity is an essential index to estimate the conduction properties of an inorganic compound. For the films with homogeneous thickness, via testing the film’s square resistance by the four-point-probe method, the electrical resistivity, ρ, can be calculated by:
ρ = R S × d
where RS and d refer to square resistance and film thickness, respectively. Table 2 lists all the calculated electrical resistivities for the TiN films #1–#10. The three graphs pictured in Figure 5 reveal the variation in electrical resistivity in the case of various process parameters. Figure 5 demonstrates that TiN films with different electrical resistivities can be achieved by adjusting the depositing parameters, and it is more likely that TiN films with low electrical resistivity are prepared when there is a N2 flow rate of 10:15, sputtering power of 100 W, and sputtering pressure of 1.6 Pa. In fact, different process parameters mainly result in various crystallizing orientations and N:Ti atomic ratios, and then influence the film lattice structure and electrical resistivity.
Figure 6 shows the relationship between atomic ratio and electrical resistivity, revealing that the electrical resistivity of TiN films #1–#10 has a tendency to become smaller when the N:Ti atomic ratio approaches 1:1. This phenomenon demonstrates that TiN shows a lower electrical resistivity when the N:Ti atomic ratio matches the pure stoichiometry [36,37], and the relationship between the atomic ratio and electrical resistivity is in accordance with the consequence reported in Lengauer’s work [38]. In fact, in the case of non-stoichiometry, TiNx, which has a typical NaCl crystal structure, has been reported to have more point defects of Ti interstitials, Ti vacancies [39], N interstitials, and N vacancies [40]. All these defects may dominate the carrier mobility of the TiN compound, in other words, influence the electrical resistivity of TiN films from the aspect of macroscopic behavior.

2.4. Crystal Structure Characterization of TiN Films

X-ray diffraction (XRD) technology is employed to characterize the crystal orientation of the sputtered TiN films with various process parameters. Here, all the XRD diffraction spectra have been analyzed according to the ICSD patterns (89/49384 @04/25/07). The TiN films deposited on glass sheet substrates were utilized to perform XRD test experiments. Figure 7 presents the XRD results of four typical TiN films, namely, #1, #3, #7, and #9. The XRD spectra in Figure 7 indicate that there is a weak diffraction peak when 2θ is 37.4° of #3 and #7, revealing the fact that when N2 is introduced, the deposited TiN film is likely to be oriented in TiN <111>. For all TiN films, when 2θ is 43.2°, there is a diffraction peak of TiN <200>, which shows that they are of the consistent stoichiometry when the deposition temperature is room temperature (RT). In addition, the XRD results reveal that TiN films are more likely to be oriented in the TiN <200> orientation when N2 is introduced. Comparing all the diffraction pictures, we find that the diffraction peak of #4 is too weak to be observed, indicating that it is a little hard to crystallize when N2 is introduced too much (gas flow rate of N2 approaches 15 sccm). The consequence indicates that it is in favor of forming a preferable lattice structure with the process parameters applied on #7.

2.5. Secondary Electron Emission Properties of TiN Films

The secondary electron emission property of TiN is a very important physical parameter that determines its application in surface plating engineering in space and vacuum environments [9,10,11,32]. The electron emission coefficient, denoted as EEC, is a physical parameter that measures the number of electrons that can be excited after the electron has collided with a solid surface. EEC is defined as the ratio of the number of electrons outgoing to that of electrons incoming in a single electron collision event. Numerous studies have been conducted to show that TiN is characterized by a low EEC [9,10,11,41,42]. For instance, in 2022, Wang et al. achieved a reduction in the EEC peak value from 3.58 to 1.47 by coating the alumina surface with a TiN film [9]. In 2024, Lian’s work showed that coating TiN on BN bulk decreased the EEC peak value from 2.38 to 1.27. Contrary to the need to apply functional layer materials with high EEC in electron multipliers [43], TiN coatings with low EEC enable the mitigation of plasma discharges induced by a secondary electron avalanche, especially in high-power microwave systems [9]. Therefore, in this work, the EEC properties of TiN films prepared under 10 groups of different process parameters were characterized.
Figure 8 demonstrates the results of EEC experimental measurements for the TiN films. The test results showed that the peak EEC of the prepared TiN films ranged from 1.53 to 2.01. Samples #1 and #2 with nanostructured morphology have the lowest EEC values, with peak EEC values of 1.54 and 1.57, respectively. Moreover, samples #7 and #8 with compact film morphology have relatively low EEC values, with peak EEC values of 1.62 and 1.61, respectively. Comparatively, it can be seen that the EEC values of samples #4 and #6 are significantly larger than the others, with peak EEC values of 2.01 and 1.93, respectively.
Combined with the electrical resistivity data in Section 2.3, we drew Figure 9 to depict the relationship between film EEC data and film electrical resistivity data. As can be concluded from Figure 9, for TiN samples with compact layer structures, TiN films with lower resistivity also have relatively lower EEC values. This phenomenon is important for the application of TiN film process modulation to achieve EEC modulation, and it may be applied to other materials. We analyze this physical phenomenon from the perspective of the physical mechanism of electron emissions. Whether excited inner secondary electrons can be emitted and what their emission probability is are both related to the scattering they experience during their motion within the solid. During their motion, inner secondary electrons are scattered by free electrons. Secondary electrons that undergo multiple scatterings suffer significant energy loss and have a reduced probability of escape. Therefore, the magnitude of EEC is related to the concentration of free electrons. In summary, in solids with lower resistivity, the concentration of free electrons is relatively high, leading to a high probability of scattering for secondary electrons during their motion, significant energy loss, and a low probability of escape, resulting in a low EEC. Conversely, in solids with higher electrical resistivity, the concentration of free electrons is relatively low, resulting in fewer scattering events for secondary electrons. This allows more secondary electrons to escape with minimal energy loss, leading to a higher EEC.

3. Materials and Methods

3.1. TiN Film Preparation

In the experimental section, N-type silicon <100> with low resistivity (≤2 × 10−4 Ω·m) and glass sheet were employed as substrate, a high-purity (99.99%) TiN target (diameter 50.8 mm, thickness 5 mm) was used as the sputtering source, and high-purity Ar and high-purity N2 were used as working gas and reactive gas, respectively. An atmosphere formed by a mixture of Ar and N2 was well prepared before sputtering. Detailed procedures are illustrated as follows. First, the silicon substrates and glass sheet substrates were cleaned in an ultrasonic bath with acetone, alcohol, and ultrapure water in turn in order to eliminate any possible impurities. All the substrate samples were blown with N2. The vacuum chamber was pumped down to a base pressure of 3 × 10−4 Pa before Ar and N2 were introduced. During the deposition, the pressure inside the chamber was adjusted from 0.8 Pa to 2.0 Pa in order to explore the influence of sputtering pressure on the quality of the films. Gas flow meters were employed to accurately control the flow rate of N2 and Ar during deposition, so that the elemental content of TiN films could be controlled by adjusting the gas flow rate. The sputtering power ranged from 100 W to 160 W so as to establish the influence of the sputtering power on the properties of the films. Detailed process parameters for every sample are listed in Table 3. It deserves to be mentioned that the substrate temperature of all experiments was RT, and the sputtering time of all samples was 180 min. In addition, the rotational velocity of the specimen holder was set to 0.1 rad/s in order to prepare the films with uniform texture.

3.2. Physical Characterization Methods

As for the analysis experiments, XRD (Rigaku D/MAX-2400, Tokyo, Japan) was applied to analyze the lattice structure and crystalline quality of the TiN films, and the scanning range of 2θ ranged from 20° to 70°, and the step was 0.02°. The surface and cross-section morphology were characterized by SEM (Hitachi S-4800, Tokyo, Japan). Elementary content of the TiN films was analyzed by EDS (Accessory, Hitachi S-4800, Tokyo, Japan). Surface condition of the TiN films was characterized by XPS (Axis-UltraDLD, Kratos, Manchester, UK). In addition, a four-point-probe meter (Ximei RTS-8, Canton, China) was utilized to test the square resistance of the TiN films fabricated on glass substrates.
The EEC of TiN films was measured using the sample current method since TiN has good electrical conductivity. The principle of the sample current method for measuring EEC is as follows: by applying different bias voltages to the sample, different kinds of electrons in the secondary electron emission process can flow through the sample in the form of different strength currents, and the sample EEC can be determined by accurately measuring the various currents. The EEC measurement process can be briefly described as follows: firstly, a bias voltage of several hundred volts is applied to the sample. Under this bias voltage, almost all the escaping secondary electrons will be attracted back to the sample surface by the electric field, and the current measured at this time is the sum of all the electron beam currents in the process, IP. Then, a smaller negative bias voltage is applied to the sample (−30 V in the experiment), and under this bias voltage, all the secondary electrons generated during the process will be accelerated away from the sample surface by the repulsive effect of negative bias on the surface of the sample. At this point, the measured current IS is the total electron beam current IP minus the escaping electron beam current. In the case of obtaining the values of IP and IS, the sample EEC can be calculated by the following formula:
EEC = I P − I S I P

4. Conclusions

In this work, by employing RF reactive magnetron sputtering with various process parameters, TiN films with a compact structure and a loose nanostructure were achieved. The influence of gas flow rate, sputtering power, and pressure on the morphology, composition, and electrical properties of TiN films was investigated and analyzed. By comparing the EEC and electrical resistivity of the TiN films, a positive correlation between the EEC characteristics of the TiN films and the film’s electrical resistivity was revealed. Four conclusions can be summarized from the study as follows: (1) Introducing an appropriate amount of N2 is an effective way to modulate the TiN film surface morphology and content of the N element during the deposition. (2) When the N:Ti atomic ratio approaches 1:1, the electrical resistivity of TiN films shows a tendency to decrease, and thereinto, sample #8 shows an extremely low electrical resistivity of 1.59 × 10−4 Ω·m. (3) This is in favor of forming a preferable crystal structure with a TiN <200> orientation by the method of RF active magnetron sputtering and the process parameters shown in this work. (4) TiN films with nanostructured morphology show a lower EEC; for TiN films with the same compact structure, TiN films with low resistivity show a lower EEC, and this novel discovery is highly valuable for research into the EEC modulation of TiN films. In this work, the sputtering process and physical property parameters of TiN films have been carefully investigated, which is valuable for engineering scenarios where TiN is applied as a functional coating.

Author Contributions

Conceptualization, D.W.; methodology, Y.X. and D.W.; software, Y.X.; validation, Y.X. and D.W.; formal analysis, Y.X.; investigation, Y.X.; resources, Y.X.; data curation, Y.X. and D.W.; writing—original draft preparation, Y.X. and D.W.; writing—review and editing, D.W.; visualization, Y.X.; supervision, D.W.; project administration, Y.X.; funding acquisition, Y.X. All authors have read and agreed to the published version of the manuscript.

Funding

This work was supported by the Project of Science and Technology Research Program of Chongqing Technology and Business Institute of China (No. NDQN2022-01).

Institutional Review Board Statement

Not applicable.

Informed Consent Statement

Not applicable.

Data Availability Statement

The original contributions presented in the study are included in the article; further inquiries can be directed to the corresponding authors.

Conflicts of Interest

The authors declare no conflicts of interest.

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Inorganics 13 00201 g001
Figure 1. Surface morphology photos and cross-section images of TiN films #1–#4 characterized by SEM: (a–d) are the top view of SEM photos for #1–#4 samples, and (e–h) are the corresponding section view photos.
Figure 1. Surface morphology photos and cross-section images of TiN films #1–#4 characterized by SEM: (a–d) are the top view of SEM photos for #1–#4 samples, and (e–h) are the corresponding section view photos.
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Figure 2. Variation tendency of the approximately calculated depositing velocity for the prepared TiN films #1–#10 with various process parameters: (a) influence of gas flow rate on depositing velocity, (b) influence of sputtering power on depositing velocity, (c) influence of sputtering pressure on depositing velocity.
Figure 2. Variation tendency of the approximately calculated depositing velocity for the prepared TiN films #1–#10 with various process parameters: (a) influence of gas flow rate on depositing velocity, (b) influence of sputtering power on depositing velocity, (c) influence of sputtering pressure on depositing velocity.
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Figure 3. Variation tendency of atomic ratio for the prepared TiN films #1–#10 with various process parameters: (a) influence of gas flow rate on atomic ratio, (b) influence of sputtering power on atomic ratio, (c) influence of sputtering pressure on atomic ratio.
Figure 3. Variation tendency of atomic ratio for the prepared TiN films #1–#10 with various process parameters: (a) influence of gas flow rate on atomic ratio, (b) influence of sputtering power on atomic ratio, (c) influence of sputtering pressure on atomic ratio.
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Figure 4. (a) Surface conditions characterization of #3 sample by XPS, and (b) Ti 2p XPS fine spectrum of #3 sample; the gray line is the measured XPS spectrum of #3 sample, it shows that the deposited TiN coating is a mixture formed by TiON and TiN.
Figure 4. (a) Surface conditions characterization of #3 sample by XPS, and (b) Ti 2p XPS fine spectrum of #3 sample; the gray line is the measured XPS spectrum of #3 sample, it shows that the deposited TiN coating is a mixture formed by TiON and TiN.
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Figure 5. Variation tendency of electrical resistivity for the prepared TiN films #1–#10 with various process parameters: (a) influence of gas flow rate on electrical resistivity, (b) influence of sputtering power on electrical resistivity, (c) influence of sputtering pressure on electrical resistivity.
Figure 5. Variation tendency of electrical resistivity for the prepared TiN films #1–#10 with various process parameters: (a) influence of gas flow rate on electrical resistivity, (b) influence of sputtering power on electrical resistivity, (c) influence of sputtering pressure on electrical resistivity.
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Figure 6. Relationship between the N:Ti atomic ratio and electrical resistivity of TiN films #1–#10.
Figure 6. Relationship between the N:Ti atomic ratio and electrical resistivity of TiN films #1–#10.
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Figure 7. XRD test results of #1, #3, #7, and #9 TiN film samples; TiN <111> corresponds to a diffraction peak with 2θ of 37.4°, and TiN <200> corresponds to a diffraction peak with 2θ of 43.2°.
Figure 7. XRD test results of #1, #3, #7, and #9 TiN film samples; TiN <111> corresponds to a diffraction peak with 2θ of 37.4°, and TiN <200> corresponds to a diffraction peak with 2θ of 43.2°.
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Figure 8. Measured electron emission coefficient, EEC, results of #1–#10 TiN film samples, versus primary electron energy, PEE: (a) EEC of TiN films #1–#4 with various gas flow rate, (b) EEC of TiN films #3, #5–#7 with various sputtering power, (c) EEC of TiN films #3, #8–#10 with various sputtering gas pressure.
Figure 8. Measured electron emission coefficient, EEC, results of #1–#10 TiN film samples, versus primary electron energy, PEE: (a) EEC of TiN films #1–#4 with various gas flow rate, (b) EEC of TiN films #3, #5–#7 with various sputtering power, (c) EEC of TiN films #3, #8–#10 with various sputtering gas pressure.
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Figure 9. The EEC peak value data of TiN films #3–#10 versus the corresponding electrical resistivity.
Figure 9. The EEC peak value data of TiN films #3–#10 versus the corresponding electrical resistivity.
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Table 1. Tested approximate values of coating thickness and atomic ratio of N:Ti, as well as the calculated depositing velocity of the TiN films #1–#10.
Table 1. Tested approximate values of coating thickness and atomic ratio of N:Ti, as well as the calculated depositing velocity of the TiN films #1–#10.
Sample No.Thickness (nm)Depositing Velocity (nm/min)Atomic Ratio (N:Ti)
#14462.470.587
#23892.160.792
#33732.071.02
#43551.971.40
#53962.201.03
#64222.341.10
#74592.551.01
#83942.190.991
#93772.090.948
#103842.130.972
Table 2. Tested and calculated data of the TiN films #1–#10.
Table 2. Tested and calculated data of the TiN films #1–#10.
Sample No.Square Resistance (Ω/□)Thickness (nm)Electrical Resistivity (Ω·m)
#12.33 × 1054461.04 × 10−1
#21.41 × 1053895.48 × 10−2
#31.38 × 1033735.15 × 10−4
#45.15 × 1053551.83 × 10−1
#51.90 × 1033967.52 × 10−4
#61.66 × 1044227.01 × 10−3
#76.01 × 1024592.76 × 10−4
#84.04 × 1023941.59 × 10−4
#95.33 × 1033772.01 × 10−3
#101.80 × 1033846.91 × 10−4
Table 3. Statistical results of the process parameters for the fabrication of TiN films #1–#10.
Table 3. Statistical results of the process parameters for the fabrication of TiN films #1–#10.
Sample No.N2:Ar (sccm)Sputtering Power (W)Sputtering Pressure (Pa)
#10:151001.2
#25:151001.2
#310:151001.2
#415:151001.2
#510:151201.2
#610:151401.2
#710:151601.2
#810:151201.6
#910:151202.0
#1010:151200.8
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Xia, Y.; Wang, D. Effect of Sputtering Process Parameters on Physical Properties and Electron Emission Level of Titanium Nitride Films. Inorganics 2025, 13, 201. https://doi.org/10.3390/inorganics13060201

AMA Style

Xia Y, Wang D. Effect of Sputtering Process Parameters on Physical Properties and Electron Emission Level of Titanium Nitride Films. Inorganics. 2025; 13(6):201. https://doi.org/10.3390/inorganics13060201

Chicago/Turabian Style

Xia, Yang, and Dan Wang. 2025. "Effect of Sputtering Process Parameters on Physical Properties and Electron Emission Level of Titanium Nitride Films" Inorganics 13, no. 6: 201. https://doi.org/10.3390/inorganics13060201

APA Style

Xia, Y., & Wang, D. (2025). Effect of Sputtering Process Parameters on Physical Properties and Electron Emission Level of Titanium Nitride Films. Inorganics, 13(6), 201. https://doi.org/10.3390/inorganics13060201

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