Chemical Vapor Deposition TiN Research Articles

Early stage of tin oxide film growth in chemical vapor deposition

Early stage of film growth was studied for chemical vapor deposition tin oxide films. Nucleation of films was observed by using an atomic force microscope. It was found nucleation structure of the crystallites changed from isolated island-like to tightly interconnected as methanol concentration into source gases increased.

Density functional study on the adsorption and surface reactions on SiO 2 in TiN-CVD using TiCl 4 and NH 3

We have investigated the following surface reactions theoretically, in order to elucidate the mechanism of the initial step of TiN chemical vapor deposition (CVD) on amorphous SiO 2 surfaces using TiCl 4 and NH 3 as material gases: (i) adsorption of TiCl 4 and NH 3 onto the SiO 2 surface; (ii) surface reactions of the Langmuir–Hinshelwood mechanism and the Eley–Rideal mechanism between the adsorbates produced by TiCl 4 and NH 3; and (iii) reactions of TiCl 4 and NH 3 with surface OH groups of SiO 2. The energetics of these surface reactions were calculated by using the BLYP density functional theory (DFT) with cluster models of amorphous SiO 2 surfaces.

Chemical vapor deposition of copper film from hexafluoroacetyl-acetonateCu (I)vinylcyclohexane

An organometallic precursor, (hexafluoroacetyl-acetonate, hfac)Cu (I)(vinylcyclohexane, VCH) was studied for metallorganic chemical vapor deposition of copper thin films. The vapor pressure of (hfac)Cu (I)(VCH) is approximately 0.1 torr at 40°C and no appreciable amount of precipitation was observed while holding at 65°C for 1 month. The resistivity, purity, texture, adhesion, conformality and surface morphology of the film were investigated. The (hfac)Cu (I)(VCH) allowed the deposition at temperatures as low as 75°C. Copper film had a low resistivity of approximately 2.0 μΩ·cm for deposition temperatures ranging from 125 to 175°C. The copper film on physical vapor deposition (PVD) TiN was continuous and smoother than on chemical vapor deposition (CVD) TiN. The concentration level of impurities, including C, F and O at the interface was lower on PVD TiN than on CVD TiN. Films deposited at higher temperature showed better adhesion. It is believed that (hfac)Cu (I)(VCH) is stable with low vapor pressure and suitable as a precursor for seed layer formation with conformal coverage.

X-ray photoelectron spectroscopic characterization of the adhesion behavior of chemical vapor deposited copper films

Adhesion behavior of chemical vapor deposited (CVD) copper (Cu) films on various barrier substrates was studied using a pull-off test. The mean adhesion strength of Cu films on air-exposed physical vapor deposition (PVD) Ta, air-exposed CVD TiN, in situ PVD TiN, and in situ CVD TiN were determined to be 3.42, 4.74, 4.64, and 10.24 MPa, respectively. The adhesion of Cu films on the in situ PVD TiN exhibited almost the same strength as the adhesion on the air-exposed CVD TiN. Root-mean-squared (rms) roughness values for air-exposed CVD TiN and in situ PVD TiN are 8.06 and 1.18 nm, respectively. The rougher surface morphology of the air-exposed CVD TiN films was considered to improve adhesion due to mechanical anchoring. The adhesion strength of the Cu film on the in situ CVD TiN was two times higher than that on the air-exposed CVD TiN. In order to examine the adhesion difference, x-ray photoelectron spectroscopy (XPS) measurement was performed on the exposed interface after pulling off the Cu film. The XPS results showed that on the in situ barrier Cu(OH)2 was formed at the surface, but on the air-exposed barrier Cu(OH)2 was not formed. Consideration of the Ti 2p spectra and the Cu 2p spectra indicated that the native oxide composition of the barrier surface affects the adhesion characteristics in the same way as the oxidation resistance of the Cu atoms. Since the amount of residual F was only 3 to 4 at. % at the interface, the effect of F on the adhesion was not as important as that of the native oxide.

Degradation of Ta2O5 Gate Dielectric by TiCl4-Based Chemically Vapor Deposited TiN Film in W/TiN/Ta2O5/Si System

Tantalum pentoxide was adopted as a gate dielectric for obtaining gate oxide with less than 3.0 nm SiO2 equivalent thickness and low leakage current. Physical vapor deposited (PVD) TiN or TiCl4-based chemical-vapor-deposited (CVD) TiN was used as the barrier material between the W electrode and Ta2O5 layer. The thermal stability and electrical property of each barrier were evaluated at an elevated temperature of 900°C. In the as-deposited condition and after annealing at 800°C, PVD and CVD TiN show similar electrical properties. However, after annealing at 900°C, CVD TiN barriers show much lower breakdown fields and higher leakage current compared with PVD TiN, indicating that CVD TiN has worse barrier performance than PVD TiN. Microvoids are formed in the Ta2O5 layer along the PVD TiN/Ta2O5 interface after annealing at 900°C. It is found that Ta diffuses into the TiN layer leaving microvoids behind. Ta2O5 is more severely damaged in the CVD TiN system after annealing. The high content of residual Cl in CVD TiN was found to reduce Ta2O5 and generate free Ta and O. Free Ta and O atoms that are generated from the reduction of Ta2O5 diffuse into the TiN layer and hence produce macrovoids and disconnected areas in the Ta2O5 layer. The transmission electron microscopy (TEM) images and secondary ion mass spectrometry (SIMS) depth profiles are in good agreement with the electrical properties of W/TiN/Ta2O5/Si gate devices.

Application of plasma chemical vapour deposition of TiN to HSS precision bearings

The paper reports the application of plasma chemical vapour deposition (PCVD) of TiN to high speed steel precision bearings. The surface metallurgical characteristics of the coatings were determined by employing surface and structural analytical techniques, i.e. scanning electron microscopy, Auger electron spectroscopy, and X-ray photoelectron spectroscopy. The layer adhesion of the coatings was evaluated by means of the scratch test. Experiments on oxidation and thermal shock resistance were also carried out. The results demonstrated good adhesion between TiN coating and high speed steel substrate. Test results showed that using PCVD, uniform coatings can be achieved having good oxidation resistance in air and good thermal shock resistance between 580°C and room temperature. The tests showed that bearings coated with PCVD TiN worked normally and satisfied the working conditions.

Electrical Characteristics and Thermal Stability of W, WN x , and TiN Barriers in Metal / Ta2 O 5 / Si Gate Devices

Tantalum pentoxide was adopted as gate dielectric for obtaining gate oxide with less than 3.0 nm of equivalent thickness and low leakage current. Physical vapor deposited (PVD) W, PVD PVD TiN, or chemical vapor deposited (CVD) TiN was used as gate/barrier material on Thermal stability and electrical property of each barrier were evaluated at elevated temperature of 900°C. W and barriers show much lower leakage current than TiN barriers at both low and high fields. Leakage current is lower with barrier than with W barrier at high field. The breakdown characteristics of W and barriers are noticeably improved after annealing at 900°C because of the recovery from sputtering damage. The breakdown characteristic of is superior to W and this is thought to come from the incorporation of nitrogen into the layer. Breakdown property is not degraded significantly in the samples with PVD TiN barrier. However, the samples with CVD TiN barrier show significant degradation in electrical property at the elevated temperature. Microvoids are formed in layer along the interface in PVD TiN sample after annealing at 900°C. Ta diffuses into the TiN layer leaving voids behind. is more severely damaged in the CVD TiN sample. Diffusion of Ta and O becomes significant in this sample after annealing. The Cl content is also much higher in CVD TiN samples than PVD TiN samples. Thus residual Cl is considered to be the main reason for the degradation of in the devices containing CVD TiN as a barrier material. © 2001 The Electrochemical Society. All rights reserved.

Electromigration Characterization of Damascene Copper Interconnects: Comparison Between CVD Copper and ECD Copper.

ABSTRACTWe have characterized the electromigration performance of copper damascene interconnects using moderately and highly accelerated lifetime tests respectively at package and wafer level. Two metallizations have been studied: Chemical Vapor Deposition (CVD) copper deposited on CVD TiN (Process A) and electroplated (ECD) copper deposited on CVD TiN using 90 nm of CVD copper as a seed-layer (Process B). All metallizations were passivated with SiO2. Two line widths have been characterized: 0.6μm and 4μm.For wide lines, we obtained similar activation energies (Ea) for both metallizations (0.63 for process A and 0.65 eV for process B). For narrow lines, the Ea value is 0.8eV for CVD copper whereas it is higher than 1eV for ECD copper. For wide lines of both metallizations, failure analysis performed with a Scanning Electron Microscope (SEM) gave clear evidences that microstructural gradients have a strong impact on voids and extrusions formation (i.e. that grain boundaries are an active diffusion path in spite of low Ea values). For narrow lines, diffusion at the upper interface is believed to be the main diffusion path.From the reliability point of view, the extrapolated lifetimes of the metallization including ECD copper are much higher (1 to 2 orders of magnitude depending on the line width) than for CVD copper.

Analysis of Electromigration Extrusion Failure Mode in Damascene Copper Interconnects

ABSTRACTThe electromigration performance of copper damascene interconnects has been studied with respect to hillock formation and is compared to void formation failure mode. The metal lines consisted of Chemical Vapor Deposition (CVD) copper deposited on CVD TiN and capped with SiN. SiO2 was used for copper lines insulation and final passivation. Two line widths (0.5 and 3µm) have been characterized. It is shown that higher activation energy values are obtained for void formation failure mode, respectively Ea = 0.86 eV for wide lines (poly-grain microstructure) and Ea =1.04 eV for narrow lines (quasi-bamboo microstructure) than for extrusion failure mode. Failure analysis performed with a Scanning Electron Microscope (SEM) showed that grain boundaries are active diffusion paths in polycrystalline copper lines whereas interface diffusion is believed to be the main diffusion path in narrow lines. Extrusions are shown to occur at the upper interface of copper damascene lines and to extend laterally as a consequence of cracks in dielectric layers and are thus responsible for short circuit between adjacent lines. Implications on extrapolated lifetimes at operating conditions are discussed.

The pentacoordinate titanium complex [TiCl2(NMe2)2(HNMe2)

Amido complexes of titanium are useful reagents in a variety of syntheses and as precursors for chemical vapour deposition of TiN. The title compound, di­chloro­bis­(di­methyl­amido)(di­methyl­amine)­titanium(IV), [TiCl2(C2H6N)2(C2H7N)], crystallizes with one mol­ecule in the asymmetric unit. The neutral complex shows an unusual fivefold coordination of the titanium centre with a distorted trigonal–bipyramidal geometry and the di­methyl­amine mol­ecule occupying an axial position.

Chemical vapor deposition of titanium nitride thin films from tetrakis(dimethylamido)titanium and hydrazine as a coreactant

Hydrazine was used as a coreactant with tetrakis(dimethylamido)titanium for the low-temperature chemical vapor deposition of TiN between 50 and 200 °C. The TiN film-growth rates ranged from 5 to 45 nm/min. Ti:N ratios of approximately 1:1 were achieved. The films contain between 2 and 25 at.% carbon, as well as up to 36 at.% oxygen resulting from diffusion after air exposure. The resistivity of these films is approximately 104 μΩ cm. Annealing the films in ammonia enhances their crystallinity. The best TiN films were produced at 200 °C from a 2.7% hydrazine–ammonia mixture. The Ti:N ratio of these films is approximately 1:1, and they contain no carbon or oxygen. These films exhibit the highest growth rates observed.

Retarding Effect of HCl on Rate of Chemical Vapor Deposition of TiN from TiCl4 ‐ H 2 ‐ N 2

The deposition rate of TiN was measured in a hot‐wall chemical vapor deposition reactor using gas mixtures at 1 bar total pressure and 950–1470 K. With respect to HCl, the reaction order was found to be −3. From the experimental results, a reaction model was derived that assumes (Reaction I) to be the rate‐determining reaction in the homogeneous gas phase, and (Reaction III) to be the slow heterogeneous step. The heterogeneous reaction preceding Reaction III, which may be described as (Reaction II) , was assumed to be sufficiently fast to attain equilibrium. Reaction II accounts for the strongly retarding effect of HCl on the rate of TiN deposition. By proper adaptation of the rate constants and the activation energies of Reactions I and III, the numerical simulation led to deposition rates in good agreement with the measured values. © 2000 The Electrochemical Society. All rights reserved.

Integration of Chemical Vapor Deposition Aluminum and Physical Vapor Deposition Aluminum for Aluminum Plug Process of Sub-Quarter Micron Devices

A chemical vapor deposition (CVD)-physical vapor deposition (PVD) Al plug process was successfully integrated to fabricate device wafers with sub-quarter micron technology. Metalorganic CVD (MOCVD) TiN stacked on ion metal plasma (IMP) Ti was used as the underlayer of CVD Al from dimethylaluminum hydride (DMAH). Thin, conformal CVD Al film deposited at a low temperature functioned as an effective wetting layer for PVD Al reflow. If the CVD Al film is too thick, a complete via fill is not achieved. After PVD Al reflow, Al bumps were observed atop the via, which originated from the abnormal growth of the Al grain with a non-<111> direction. A two-step PVD Al process was applied for bump removal, because a thin PVD Al layer deposited at low temperature with high power acted as a seed layer for grain growth. The CVD-PVD Al plug process exhibited via resistance and electromigration resistance superior to those of the conventional W plug process.

Atmospheric pressure chemical vapour deposition of tin(ii) sulfide films on glass substrates from Bun3SnO2CCF3 with hydrogen sulfide

In a search for a mild, rapid, moderately low temperature route to the deposition of thin films of tin(II) sulfide (SnS) on glass, we have investigated the APCVD reaction of tri-n-butyltin trifluoroacetate with hydrogen sulfide at 350–600 °C under nitrogen. The films deposited over a 15 min period were shown to be SnS by X-ray diffraction, Raman microscopy, EDAX, SEM and XPS. The conditions established are attractive for the large scale, rapid production of tin(II) sulfide films.

Effectiveness of Ti, TiN, Ta, TaN, and W2N as barriers for the integration of low-k dielectric hydrogen silsesquioxane

The interactions between low-k (dielectric constant) material hydrogen silsesquioxane (HSQ) and barrier layers, Ti, Ta, physical-vapor deposited (PVD), and chemical-vapor deposited (CVD) TiN, PVD TaN, and CVD W2N, have been investigated by using sheet-resistance measurement, x-ray diffraction, transmission electron microscopy, Rutherford backscattering spectrometry, elastic resonance scattering, and forward recoil spectrometry. The conventionally used dielectric PETEOS [plasma-enhanced chemical vapor deposition tetraethylorthosilicate (TEOS)] was also studied as a control. The results show that none of these barriers except Ti can react with HSQ and PETEOS at elevated temperatures. However, significant outdiffusion of hydrogen due to the degradation of the HSQ films upon annealing exists for all barrier/HSQ structures, and exhibits a strong barrier dependence. Metal barriers Ti and Ta, and CVD TiN can retard the H outdiffusion, whereas PVD TaN and PVD TiN induce the H outdiffusion from the HSQ films. The microstructural and structural considerations and a proposed “nitride effect” mechanism can give some reasonable interpretations to these observations. Upon annealing, the structural and/or compositional changes of these barrier films give rise to corresponding sheet resistance variations. The phase transformation of the Ta film on HSQ is completely inhibited because of the possible role of diffusing H atoms, as compared to the phase transformation occurring in the Ta film on PETEOS.

Microstructure and property changes caused by diffusion during CVD coating of steels

Abstract The interdiffusion of carbon and titanium between a substrate and coating during chemical vapor deposition (CVD) coating of steels influences the microstructures and properties of the coating/substrate compounds. The CVD parameters atmosphere, temperature and pressure as well as the composition of the steel substrates were investigated systematically to optimize the properties of the coating/substrate compounds. The tool and carbon steels AISI H13 (DIN X40CrMoV5-1), AISI A2 (DIN X100CrMoV5-1), AISI 1045 (DIN Ck45) and ∼AISI 1095 (DIN 100V1) were coated by high-temperature CVD TiN, low-pressure CVD TiN and moderate-temperature CVD TiCN. Chemical compositions of coatings and substrates were measured by glow discharge optical spectroscopy (GDOS) and electron probe microanalysis (EPMA). Substrate and coating microstructures were examined in taper sections by light microscopy. Further, the substrate hardness was investigated in the taper sections. In an earlier work, carbon diffusion near the interface was investigated. Low coating pressures combined with high temperatures and high carbon activities of the substrates promoted the diffusion process. In this work, the investigations were extended to deeper substrate regions and to the titanium diffusion. From the carbon profiles in coatings and substrates, a carbon balance was set up for the diffusion from the substrate to the coating during CVD.

Characteristics of chemically vapor deposited TiN films prepared using tetrakis-ethylmethyl-amido-titanium

Low pressure chemical vapor deposition of TiN was studied with tetrakis-ethylmethyl-amido titanium (TEMAT) in a cold-wall-type vertical flow reactor with helium or ammonia. Thermal decomposition of the precursor under helium atmosphere yielded TiN films at substrate temperatures of 250 °C. On the contrary, the reaction of TEMAT with ammonia occurred even at 100 °C. The film growth rate increased with increasing deposition temperature and precursor mole fraction. However, deposition rate was greatly reduced in the system of ammonia/TEMAT compared to thermal decomposition probably due to a vigorous gas phase reaction in the latter case. For the case of thermal decomposition, the growth rate levels off at 325 °C and this behavior has been interpreted as a transition from surface reaction to gas phase mass transfer control. The resistivity of the films deposited under similar conditions decreased with increasing thickness. It was found that higher deposition temperature and ammonia addition produced films of lower resistivity. Air exposure of the films caused an increase in resistivity, probably by oxidation of the films. Surface morphology of the TiN films in an ammonia-free system was smoother than that in the ammonia system. Conformality of the films strongly depended on the deposition temperature, ammonia usage, and ammonia flow rate. Lowering the deposition temperature and ammonia flow rate improved the conformality. Barrier performance of the TiN films deposited under helium atmosphere to copper diffusion in the Cu/TiN/Si structure showed an evidence of copper diffusion even after annealing at 550 °C for 1 h.

Integration methodology of chemical vapor deposition TiN, chemical vapor deposition W and W chemical mechanical planarization for sub-quarter micron process application

Chemical vapor deposition (CVD) W plugs have been widely used for device metallization with excellent conformity in small contacts/vias with high aspect ratio [J. E. J. Schmitz, Chemical Vapor Deposition of Tungsten and Tungsten Silicides (Noyes, 1991)]. However, some unexpected plug fill such as plug loss and key hole exposing post tungsten chemical mechanical planarization (WCMP) still happened while going to smaller plug size and using metalorganic chemical vapor deposition (MOCVD) TiN barrier. In this study, MOCVD TiN and CVD W fill followed by WCMP for plug metallization were investigated. Extensive analysis had been conducted on various types of defective W plugs. Organic contaminants (hydrocarbon by-products) in MOCVD TiN deposition would prevent W deposition taking place inside the plug. For W wise, lower process temperature, carefully adjusted WF6/SiH4 and WF6/H2 partial pressure ratios had demonstrated better plug fill and electrical performance [T. E. Clark et al., J. Vac. Sci. Technol. B 9, 1478 (1991)]. In the WCMP approach, the effects of different oxidizer concentration in slurry were characterized. Eliminating the seam formation during the CVD W process can help avoid slurry attack in WCMP. The optimized integration scheme of MOCVD TiN barrier, CVD W, and WCMP was successfully achieved and is applied on 0.20 μm Logic production.

Comparison of Tetrakis(dimethylamido)titanium and Tetrakis(diethylamido)titanium as Precursors for Metallorganic Chemical Vapor Deposition of Titanium Nitride

Tetrakis(dimethylamido)titanium (TDMAT) and tetrakis(diethylamido)titanium (TDEAT) as precursors for metallorganic chemical vapor deposition of TiN were compared. H nuclear magnetic resonance (NMR) and differential scanning calorimetry (DSC) were used to study the thermal decomposition behavior of the liquid‐phase compounds. NMR spectra showed that TDEAT was thermally stable up to 220°C, while TDMAT began to decompose over 140°C. DSC results also confirmed that TDEAT had a better thermal stability than TDMAT. The gas‐phase reaction mechanism of the compounds monitored by in situ Fourier transform infrared spectroscopy and TDEAT was decomposed at higher temperature due to its steric hindrance effect. TDMAT and TDEAT had a similar dissociation mechanism in the liquid and gas phase. Both precursors were decomposed at high temperatures into Ti metal and dialkylamine. The deposition rate of TiN was higher with TDMAT than with TDEAT, and TiN films deposited with TDMAT showed lower carbon content and smooth surface morphology. © 1999 The Electrochemical Society. All rights reserved.

A Comparative Study of Film Properties of Chemical Vapor Deposited TiN Films as Diffusion Barriers for Cu Metallization

The diffusion barrier properties of three different kinds of chemical vapor deposited (CVD) TiN films were compared against Cu. TiN(A) film (21 nm) was deposited by the thermal decomposition of a single source of tetrakis(dimethylamido)titanium at 400°C. TiN(B) film (19 nm) was prepared by in situ plasma treatment after every 8 nm growth of TiN(A) film. Finally, TiN(C) film (28 nm) was deposited by the reaction of with at 630°C. The densities of TiN(A), TiN(B), and TiN(C) films were 2.55, 4.04, and , respectively. Both TiN(A) and TiN(B) films showed nanocrystalline microstructure with equiaxed grains, the sizes of which were about 4 and 7 nm, respectively. TiN(C) film showed a columnar grain structure with an average grain size of about 14 nm. Sheet resistance measurements, X‐ray diffractometry analyses, and etch‐pit test results consistently demonstrated that the barrier performances of TiN(A) and TiN(B) were superior to those of TiN(C). The diffusion barrier properties of CVD TiN films were discussed in view of the density and microstructure of the film. © 1999 The Electrochemical Society. All rights reserved.