Silver Metallization with Reactively Sputtered TiN Diffusion Barrier Films

This study investigates ultrathin titanium nitride (TiN) films in terms of their crystallographic structure, surface chemistry, sheet resistance and mechanical durability. These TiN ultrathin films were created by Atomic Layer Deposition (ALD) using TiCl4 and NH3 as precursors. The process consisted of 100, 200, 300 and 400 deposition cycles yielding ultrathin films 4.7, 9.4, 14.1 and 18.8 nm in thickness, respectively. Different planar substrates were employed, namely Si wafers, soda lime glasses and Ti foil. Based on image analyses, the deposition rate of 0.047 nm per cycle for ALD TiN (at 400 °C) was determined. A sheet resistance of 287 Ω/□ was achieved for the 18.8 nm film. X-ray diffraction (XRD) analysis confirmed the formation of cubic TiN with increasing crystallinity and texture with increased thickness. Sputter depth profiling in tandem with X-ray photoelectron spectroscopy (XPS) distinguished the uppermost oxidized surface from the stoichiometric TiN core in the films. Scratch tests demonstrated an enhanced adhesion and scratch resistance with ALD TiN films, aligned with the observed microstructural improvements. The comprehensive correlation between the film thickness, and their chemical composition, crystalline structure and mechanical performance highlights the vital role of ALD parameters in preparing TiN thin films for advanced technological applications.

Epitaxial titanium nitride (TiN) and titanium oxynitride (TiON) thin films have been grown on sapphire substrates using a pulsed laser deposition (PLD) method in high-vacuum conditions (base pressure <3 × 10-6 T). This vacuum contains enough residual oxygen to allow a time-independent gas phase oxidation of the ablated species as well as a time-dependent regulated surface oxidation of TiN to TiON films. The time-dependent surface oxidation is controlled by means of film deposition time that, in turn, is controlled by changing the number of laser pulses impinging on the polycrystalline TiN target at a constant repetition rate. By changing the number of laser pulses from 150 to 5000, unoxidized (or negligibly oxidized) and oxidized TiN films have been obtained with the thickness in the range of four unit cells to 70 unit cells of TiN/TiON. X-ray photoelectron spectroscopy (XPS) investigations reveal higher oxygen content in TiON films prepared with a larger number of laser pulses. The oxidation of TiN films is achieved by precisely controlling the time of deposition, which affects the surface diffusion of oxygen to the TiN film lattice. The lattice constants of the TiON films obtained by x-ray diffraction (XRD) increase with the oxygen content in the film, as predicted by molecular dynamics (MD) simulations. The lattice constant increase is explained based on a larger electrostatic repulsive force due to unbalanced local charges in the vicinity of Ti vacancies and substitutional O. The bandgap of TiN and TiON films, measured using UV-visible spectroscopy, has an asymmetric V-shaped variation as a function of the number of pulses. The bandgap variation following the lower number of laser pulses (150-750) of the V-shaped curve is explained using the quantum confinement effect, while the bandgap variation following the higher number of laser pulses (1000-5000) is associated with the modification in the band structure due to hybridization of O2p and N2p energy levels.

Cathodic arc deposition of nanocrystalline titanium nitride thin film on fluorine doped tin oxide coated glass substrate: Crystal structural, microstructural, mechanical, optical and electrical properties

Reactive magnetron sputtering technique was used to gain titanium nitride (TiN) films on W18Cr4V high-speed steel and GCr15 bearing steel substrates at low temperature. The Surface chemical composition of the films was analyzed using energy dispersive X-ray spectroscopy (EDXS) and the surface morphology was examined using atomic force microscopy (AFM). Moreover, a series of experiments have been conducted to study the relationship between interfacial bonding strength and some major technological parameters, that is, substrate surface roughness, negative bias voltage, intermediate transition layer, substrate hardness, and ion etching before deposition. The experimental results have indicated that the TiN film with typical ratio of chemical metric can be deposited on substrates using reactive magnetron sputtering technique below 140°C. The AFM image has showed that the TiN film using magnetron sputtering technique was composed of densely distributed nano-grains with uniform structure. Its surface was flat and smooth. The indentation testing results have showed that the increase of surface roughness and substrate hardness improves the bonding strength of TiN / substrate significantly. Furthermore, the bonding strength of TiN / substrate can also be improved through the following methods: (1) choosing a proper intermediate transition layer; (2) adopting ion etching before deposition and (3) increasing negative bias voltage before deposition.

Study of titanium nitride for low-e coating application

Titanium nitride films (100–300 nm) were sputter deposited from a high-purity titanium nitride target (nominal purity 99.99%) in an experimental dc-magnetron system. The gold-colored target, 5 cm in diameter, had a density of 92% of the theoretical value. X-ray diffraction indicated that the target material matched the simulated stoichiometric TiN pattern, while the deposited films showed a shift in the crystallographic plane spacing of the (111) and (200) Bragg reflections. Rutherford backscattering spectrometry (RBS) performed on titanium nitride films which were deposited on amorphous carbon substrates indicated the presence of titanium, nitrogen, and oxygen as principal components of the films. No argon was detected in the films within the sensitivity of the RBS technique. Titanium to nitrogen atomic ratios in the films varied from 0.83 to 1.02 according to the RBS results. The binding energy measured by x-ray photoelectron spectrometry (XPS) indicated that Ti and N were present in compound form. The effect of substrate temperature deposition, dc bias, and nitrogen content in the sputtering gas were correlated to the stoichiometry and resistivity of the films. High rates of deposition (3.8 nm/s) on hot Si(100) substrates produced films with a resistivity as low as 40 μΩ cm. The performance of the TiN films as a diffusion barrier was evaluated in a Al/TiN/TiSi2/Si(100) layered structure.

Properties of titanium nitride (TiN) films deposited by reactive sputtering and dc magnetron sputtering from composite target are studied. In the as-deposited films, a TiN (200) grain, which is the lowest energy grain and is dominant in bulk TiN, is grown in films from composite target. A resistivity of 44 µΩ-cm is attained. These results show that high quality TiN films can be deposited by dc magnetron sputtering employed TiN composite target. However, a TiN (111) grain is grown in TiN films by the nitridation of Ti. Nitridation of a reactively sputtered TiN film in ammonium is also studied. The TiN films deposited from composite target and formed by the nitridation of titanium show good barrier performance in Al-Si/TiN/Si Ohmic contact.

Coating of Ti-6Al-4V alloy substrates with TiN/Ti multi-layered films by magnetron sputtering in Ar gas atmosphere was examined, aiming at the application of the alloy to artificial heart valves, in order to improve not only the adhesion between the deposited film and the alloy but also the surface smoothness of titanium nitride coatings and thereby to improve the blood compatibility as well as the biocompatibility of the alloy coated with the titanium nitride film. The effects of the thickness of the TiN (titanium nitride) layer on the surface morphology of the film were investigated, in order to develop TiN coatings with higher blood compatibility. The multi-layered films were deposited by sputtering in sequence pure titanium and titanium nitride targets. The thickness of titanium nitride layer was varied from 300 nm to 800 nm, while that of pure titanium was constantly 200 nm. Under visual observation, the obtained multi-layered films looked yellow gold and appeared to be uniform and adhesive, while TiN monolithic films deposited directly onto the alloy substrate under the same sputtering conditions peeled off partly. Therefore it was found that the multi-layered thin films were more adhesive to the alloy than the monolithic films. According to AFM (Atomic Force Microscope) images for both of the films, the surface morphology of each TiN layer observed under the scope of nanometer-scaled area was rough with pits and bumps, while that under the scope of micrometer-scaled area was smooth without such pits and bumps. Furthermore based on the AFM, the surface roughness measured under the area of nanometer scale was found to increase with the increase of the thickness of the TiN layer in the multi-layered film, although that measured under the area of micrometer scale was assumed to be independent of the thickness of the TiN layer.

采用阳极氧化法在抛光后的钛片表面制备了粗糙的TiO2膜电极，经氨气氮化还原后将前驱体TiO2转化为氮化钛(TiN)。XRD、SEM和EDS表征分析发现，850℃氮化处理后，氮化钛电极表面具有花状凸起结构，氮化钛的主要成分为Ti2N和TiN，N元素的含量达到了32.14%。实验研究了多巴胺在该电极的电化学行为，发现TiN电极对多巴胺有良好的电催化作用。在0.1 M磷酸缓冲溶液中，采用计时电流法和差分脉冲伏安法测定了TiN电极对多巴胺的检出限，分别为1.3 μM和0.33 μM。在100 μM抗坏血酸存在下，TiN电极对多巴胺的检出限为0.56 μM。TiN电极具有较好的重现性。单个电极对25 μM DA重复测定5次，相对标准偏差(RSD)为3.97%；新制的4根膜电极在含25 μM DA的溶液中测试所得的相对标准偏差为4.2%。 A roughened titanium nitride (TiN) film is fabricated on a polished Ti substrate through anodic oxidation process and subsequent nitridation in ammonia atmosphere. The composition and morphology were characterized by XRD, SEM and EDS. The results indicate that, after the nitriding process annealed at 850˚C, the surface of TiN film is of flower convex structure, with Ti2N and TiN as the main nitride phase, and the content of N element (Atom%) reached 32.14%. Experiments have conducted to explore the electrochemical behavior of dopamine (DA) at TiN film. It is found that TiN film has good electrocatalytic activity for dopamine. Chronoamperometry and differential pulse voltammetry (DPV) were used to determine the detection limit of DA in 0.1 M phosphate buffer solution. The detection limits by two methods were calculated to be 1.3 μM and 0.33 μM. And the detection limit of DA in the presence of 100 μM ascorbic acid was calculated to be 0.56 μM. Furthermore, TiN film exhibits a good repeatability with the relative standard deviation (RSD) of 3.97% for 5 parallel detections in 25 μM dopamine using a single TiN electrode, and the RSD of 4 new electrodes is 4.2%.

(Ti,Zr)N films were prepared by dc reactive magnetron sputtering from a Ti-5 atom % Zr alloy target in N 2 /Ar gas mixtures and then employed as diffusion barriers between Cu thin films and Si substrates. Material characteristics of the (Ti,Zr)N film were investigated by X-ray photoelectron spectroscopy and cross-sectional transmission electron microscopy (XTEM). The (Ti,Zr)N film microstructure was an assembly of Very small columnar crystallites with a rock-salt (NaCI) structure. Metallurgical reactions of Cu/(Ti,Zr)N 0 . 9 5 /Si, Cu/(Ti,Zr)N 0 . 7 6 /Si, and Cu/TaN 0 . 7 1 /Si were studied by X-ray diffraction and sheet resistance measurements. The variation percentage of sheet resistance for all Cu/barrier/Si systems stayed at a constant value after annealing up to 500°C for 30 min. However, the sheet resistance increased dramatically after annealing above 750°C for Cu/(Ti,Zr)N 0 . 9 5 /Si, and 500°C for both Cu/(Ti,Zr)N 0 . 7 6 /Si and Cu/TaN 0 . 7 1 /Si. For these samples, the interface deteriorated seriously and formationof Cu 3 Si was observed by XTEM. Our results suggest thai the refractory binary metal nitride film, (Ti,Zr)N, can be used as a diffusion barrier for Cu metallization as compared to the well-known TaN film.

Titanium nitride (TiN) has been extensively studied in semiconductor devices because of its ideal thermal, mechanical, and electrical properties, along with its ability to act as a diffusion barrier to WF6 during W metal fill. Similarly, tantalum nitride (TaN) is being utilized as a diffusion barrier on SiOCH to Cu, as Cu can readily diffuse, causing device reliability issues. Metal halide precursors are typically preferred over organometallic grown films when there is no concern about substrate etching; however, organometallic-grown films usually contain higher levels of carbon and oxygen contamination, which has been correlated with an increase in film resistivity. Plasma enhanced-ALD TiN has been shown to achieve optimal growth rates with lower contamination at temperatures below 350°C, but the film and underlying substrate can suffer from plasma-induced damage. In this study, low temperature thermal ALD TiNx from anhydrous N2H4 and TiCl4 was performed on SiO2, and the deposited films were studied using x-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). TaNx films were grown utilizing N2H4 and tris(diethylamido)(tertbutylimido) tantalum(V) (TBTDET) and characterized similarly. In situ XPS was employed to demonstrate pulse saturation during ALD for TiCl4 + N2H4 à TiNx. AFM showed that 40 cycles of TiCl4 + N2H4 at 300°C produces pinhole-free, conformal films. Additionally, the effect of air exposure on TiNx films was studied; O attacked the TiNx film, evidenced by observing a 1.5 eV BE shift of the Ti 2p 3/2 peak. A comparison was made of the TiNx films grown at 300ºC and 400ºC with NH3 vs. N2H4; even at 400ºC there was approximately 2x more O and C and 50% more Cl in NH3 grown films. Furthermore, N2H4 films showed lower resistivities, attributed to lower contamination and likely better nucleation density, especially at 300oC. In situ XPS was also used to study TaNx films grown using TBTDET and N2H4. To study the nucleation on SiO2, an initial TBTDET exposure was performed; the Ta 4d peak position confirmed the nucleation and formation of Si-O-Ta bonds. After subsequent cycles, the Ta 4d peak shifts ~2eV toward lower binding energy upon forming Ta-N bonds. While the films were of extremely high purity with stoichiometry resembling Ta3N5, the N2H4 was unable to reduce the Ta oxidation state from films grown between 100oC and 300oC showing the need for some metals for the use of low oxidation state precursors or a stronger, highly energetic reducing agent. These studies with anhydrous N2H4 show the potential to form high purity barrier layers using low temperature thermal ALD as long as highly energetic reactants are used.

XPS study for reactively sputtered titanium nitride thin films deposited under different substrate bias

Characterization of titanium nitride (TiN) films on various substrates using spectrophotometry, beam profile reflectometry, beam profile ellipsometry and spectroscopic beam profile ellipsometry

Titanium nitride (TiN) films were deposited using tetrakis(dimethylamido)titanium (TDMAT) as a precursor. During film growth, N‐ and Ar‐ion beams with an energy of 120 eV were supplied in order to improve the film quality. The films deposited using a N‐ion beam showed a resistivity of about 320 μΩ cm and density of . The use of the N‐ion beam, however, drastically degraded the step coverage of the film (below 5% at the 0.5 × 1.5 μm contact). The films deposited using an Ar‐ion beam showed a resistivity of about 800 μΩ cm and density of . The step coverage measured at the same contact was around 30%. For comparison, the thermally decomposed film showed a resistivity of about 5800 μΩ cm and density of . Finally, the diffusion barrier properties of 50 nm thick TiN films for Cu were investigated by the etch‐pit test. The films deposited using N‐ and Ar‐ion beam failed after annealing at 600 and 650°C for 1 h, respectively, while thermally decomposed films failed at temperatures as low as 500°C. It is thought that the improvements of the diffusion barrier performance of the films deposited using a N‐ and Ar‐ion beam are the consequence of the film densification resulting from ion bombardment during film growth. © 2000 The Electrochemical Society. All rights reserved.

Retention mechanism and conductivity corrosion resistance performance of Ag doped GLC and TiN films for metal bipolar plates