Nitride Deposition Research Articles

Electron-Enhanced Atomic Layer Deposition of Titanium Nitride Films Using an Ammonia Reactive Background Gas

Electron-enhanced atomic layer deposition (EE-ALD) of titanium nitride (TiN) films was achieved using sequential exposures of tetrakis(dimethylamido)titanium (TDMAT) and low energy electrons in the presence of a continuous NH3 reactive background gas (RBG). Performing EE-ALD concurrently with a RBG is a new ALD film growth technique. The TiN EE-ALD was performed utilizing a hollow cathode plasma electron source (HC-PES). The HC-PES can deliver a high electron flux into background gases at pressures up to several mTorr. The TiN EE-ALD was conducted at temperatures of 30–70 °C using an electron acceleration voltage of 100 V and a NH3 pressure of ∼1 mTorr. The incident electron flux promotes electron stimulated desorption (ESD) and facilitates rapid nucleation and low temperature film growth. The TiN EE-ALD film growth was achieved on a variety of substrates including a native oxide on silicon, a SiO2 thermal oxide, and in situ silicon nitride films grown using electron-enhanced chemical vapor deposition (EE-CVD). Growth rates of 0.75 to 1.8 Å per cycle were measured using in situ four-wavelength ellipsometry for different TDMAT precursor exposures. Ex situ X-ray photoelectron spectroscopy (XPS) studies indicated that the TiN films were high purity and slightly nitrogen-rich. The in situ ellipsometry also measured low resistivities of ∼120 μΩ cm for the TiN films with thicknesses of ≥60 Å. These low resistivities were confirmed by ex situ four-point probe measurements and ex situ spectroscopic ellipsometry. X-ray diffraction investigations determined that the TiN EE-ALD films were crystalline. X-ray reflectivity studies also indicated that the thin TiN films had densities similar to bulk films. The high quality of the TiN EE-ALD films is attributed to the NH3 RBG. Interaction between the low energy electrons and the NH3 RBG is believed to form •NH2 and •H radical species that react with the surface during EE-ALD and improve film purity. The reactive •NH2 and •H species likely lead to nitridation and carbon removal from the films. RBGs greatly expand the possibilities for tuning film composition and properties during EE-ALD. In addition, TiN EE-ALD was accomplished on insulating substrates such as an SiO2 thermal oxide. The TiN EE-ALD is believed to be possible on insulating substrates because the secondary electron yield for electron energies of ∼100 eV is greater than unity.

Area-selective atomic layer deposition of titanium oxide and nitride on vertically aligned carbon nanotubes patterned by Aerosol Jet Printing for 3D Microsupercapacitors

This article demonstrates novel fabrication of the first interdigital 3D microsupercapacitors (MSC) using area-selective atomic layer deposition (ASALD). A unique ASALD process was developed to selectively deposit pseudocapacitive titanium oxide and nitride layers on one or both interdigitated vertically aligned carbon nanotube (VACNT) electrodes to form asymmetric or symmetric 3D MSC devices. This work compliments and expands on our previously published article exploring ALD of thin conformal coatings of TiO2 and TiN on VACNTs for 3D MSCs. Further, we demonstrate the first use of Aerosol Jet Printing, a recently developed additive manufacturing technique, to enable ASALD patterning of 3D MSC devices by direct writing of PMMA inhibitors on and adjacent to relatively thick nanostructured electrodes. The synthesis, characterization, and performance evaluation of ASALD TiN-TiO2-VACNT 3D MSCs described herein provides a novel approach for manufacturing of new nanocomposite based electrochemical energy storage microdevices that could be integrated as an on-chip power source for portable electronics. Results indicated the symmetric ASALD TiN(100)-TiO2(100)-VACNT MSC (6.55 mF cm−2) exhibited nearly two orders of magnitude (94×) improvement in specific capacitance compared to the uncoated VACNT MSC (0.07 mF cm−2), significantly improving energy density (3.28 mWhr cm−2) while maintaining high power density (2.34 mW cm−2).

Growth chemistry of cobalt nitride by plasma enhanced atomic layer deposition

State-of-the-art atomic layer deposition (ALD) and photoemission characterisation are applied to grow and characterise cobalt nitride, a material that has applications in renewable energy and semiconductor technologies. The growth process is characterised using an in situ cycle-by-cycle methodology to identify the main factors which underpin optimal material growth. The role of co-reactant dosing and substrate temperature is analysed in detail to demonstrate the impact these parameters have on the overall composition of the film. The in situ approach, combined with high-energy synchrotron-based photoemission studies of the resulting films, enables understanding of the bulk chemical properties without need for physical removal of material by sputtering. The results provide an insight into optimising plasma assisted ALD processes for deposition of cobalt nitride, and strategies for minimizing carbon incorporation into the film from the precursor ligands.

Ultrafast charge-transfer at interfaces between 2D graphitic carbon nitride thin film and carbon fiber towards enhanced photocatalytic hydrogen evolution

Homogeneous deposition of graphitic carbon nitride (g-C3N4) onto substrates on a large scale is of great interest in recyclable photocatalysis. However, g-C3N4 films prepared via conventional thermal condensation are thick and have problem of bad interface contacts with substrate, resulting in a poor photocatalytic performance. Herein, a thermal vapor condensation approach is developed for the growth of homogeneous g-C3N4 thin film on large area carbon fiber cloths (CFC). CFC serves as the template to guide g-C3N4 growth, resulting in a conformal thin overlayer of g-C3N4 on CFC surface. Moreover, a robust interaction between g-C3N4 and carbon fibers is achieved. A close stacking of g-C3N4 interlayers coupled with an efficient electron-withdrawing ability of carbon fiber expedites charge transfer and suppresses charge recombination. Consequently, the film exhibits an enhanced photocatalytic H2 evolution compared with g-C3N4 powder. A solid–gas bi-phase photocatalytic system is also constructed for manifesting remarkable superiority in gas evolution than solid–gas-liquid tri-phase system. Moreover, the sample is highly durable and recyclable, ensuring a robust, economical and environmentally friendly photocatalyst films.

Микроструктура и остаточные напряжения многослойных покрытий ZrN/CrN, полученных плазменно-ассистированным вакуумно-дуговым методом

Introduction. The current state of the art in the field of hard coatings application requires the formation of nanostructured compositions using different chemical elements. Modern hard coatings are able to combine different properties such as high hardness, wear resistance, corrosion resistance. At present, coatings formed by layer-by-layer deposition of zirconium and chromium nitrides are promising. When depositing combinations of chemical elements on various substrates, studies are required aimed at investigating its microstructure and, mainly, residual stresses formed during the deposition of multilayer coatings. The purpose of this work is to investigate the structural-phase state and residual stresses of ZrN/CrN system coatings formed by plasma-assisted vacuum-arc method from the gas phase. Research methods. Samples with coatings of zirconium and chromium nitrides deposited on substrates of hard alloy VК8 are investigated. Transmission electron microscopy is used to study the microstructural characteristics of multilayered coatings and X-ray diffraction analysis is used to quantify macroscopic stresses. Results and discussion. Based on the experimental results obtained it is found that changing the modes of deposition of multilayer ZrN/CrN coatings with regard to rotation speeds of table and substrate holder leads to variations in microstructure, morphology and internal stresses of surface layers of multilayer coatings. It is shown that by changing conditions for the multilayer coating deposition the possibilities of forming ZrN/CrN coatings on the substrate made of VK8 alloy with nanoscale thickness of coating layers open up. X-ray diffraction analysis indicates mainly insignificant stresses, and at high table and substrate rotation speeds – high compressive stresses in the multilayer coating. Transmission electron microscopy revealed that CrN and ZrN coatings have a common multilayer coating growth texture at low rotation speeds, and at high speeds a textural misorientation of the phases of the coating layers is observed. Based on the results obtained it is possible to recommend coatings of ZrN/CrN system as hard coatings.

Controlling Residual Stress and Suppression of Anomalous Grains in Aluminum Scandium Nitride Films Grown Directly on Silicon

Deposition of Aluminum Scandium Nitride (AlScN) films directly on Silicon at high Sc alloying levels, with controlled stress, and free of anomalous grains (AOGs) is demonstrated using reactive co-sputtering. The average stress and AOG formation consider the Sc alloying range between 20.3 and 36.6 atomic % and for film thicknesses from 400 nm to 1000 nm for 27.3% and 31.7% Sc alloying. The combination of a gradient seed layer and proper process gas mixture is shown to inhibit formation of AOGs in AlScN with up to 36% Sc alloying even when grown directly on Si. It is demonstrated that the total flow can be utilized to control the average film stress across the 20-36% doping range while the process gas mixture primarily impacts the density of AOG formation in the AlScN films. Bulk acoustic wave resonators fabricated from 380 nm and 485 nm thick low stress and AOG free Al <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.68</sub> Sc <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.32</sub> N films grown directly on Si demonstrate high frequency operation of 3.6 and 4.8 GHz, high electromechanical coupling >20%, and quality factors in excess of 500. [2021-0252]

Modeling and Experimental Study of Hysteresis during the Reactive Sputter Deposition of Titanium Oxides and Nitrides Using a Pulsed DC Magnetron

There is an ongoing interest in the research and application of thin film coatings containing titanium oxides and titanium nitrides, due to their properties such as photocatalytic activity, mechanical hardness, biocompatibility, and so on. Reactive sputter deposition is widely used for the production of such coatings. A characteristic of this method is the hysteresis, which leads to an ambiguous dependence of the deposition rate and the coating quality on the process conditions. There are a number of theoretical models describing reactive magnetron sputtering. One of the most advanced is the RSD2013 model. Several parameters in this model can only be determined experimentally. This article focuses on the investigation of the hysteresis during the reactive magnetron sputtering deposition process. The RSD2013 parameters that describe the experimental setup were determined, and on their basis the dependences of the characteristics of the hysteresis region on the discharge power, the type of reactive gas, and the working gas pressure were investigated. Additionally, the growth rate of the thin film coating prepared in various modes was compared with the RSD2013 model, which is in agreement with the experimental data. The results obtained from the RSD2013 model in comparison to the experimentally obtained data make it possible to provide an overview of suitable operating modes for the deposition of titanium dioxide and titanium dioxide for the magnetron sputtering device used.

From cathode to substrate: Plasma diagnostics on high power pulsed magnetron sputtering deposition of titanium nitride

The present study focuses on an approach to measure the plasma properties from cathode to substrate parallel at three different positions in the coating chamber with activated substrate bias. High power pulsed magnetron sputtering is a powerful tool for the application in various coating systems with advantageous properties. For this reason it was investigated by countless studies during the last years. Several of these studies focusing on investigating the coating and plasma properties. Moreover, they investigated the plasma properties either at a high distance from the target or at different points in time at different chamber positions. The investigated positions were in front of the substrate, in front of the target and between both of them. After the plasma diagnostic measurements by optical emission spectroscopy, titanium nitride coatings were deposited. The coating thickness and deposition rate were investigated by scanning electron microscope. The indentation modulus EIT, the indentation hardness HIT as well as the plastic Wpl and elastic work Wel were investigated by nanoindentation. The chemical composition of the coatings was investigated by glow discharge optical emission spectroscopy (GDOES). For a pulse-on time ton variation of the cathode pulse, the relative deviation between the optical emission spectroscopy and GDOES results was determined for the different chamber positions. The best fit between the optical emission spectroscopy and GDOES results were found for the optical emission spectroscopy measurements conducted closest to the substrate. The present study shows that optical emission spectroscopy measurements close to the substrate are more suitable for the prediction of coating properties than optical emission spectroscopy measurements in front of the cathode.

Physical vapor deposition of graphitic carbon nitride (g-C3N4) films on biomass substrate: optoelectronic performance evaluation and life cycle assessment

Physical vapor deposition of graphitic carbon nitride (g-C3N4) films on biomass substrate: optoelectronic performance evaluation and life cycle assessment

Study of deposition parameters of reactive-sputtered Si3N4 thin films by optical emission spectroscopy

Deposition parameters of silicon nitride in reactive direct-current magnetron sputtering were studied in two different chambers in order to establish a characterization protocol assisted by optical emission spectroscopy. Different discharge powers, working pressures and gas proportions (N2:Ar) were used to create characterization curves to identify the optimum conditions for the synthesis of silicon nitride. These curves were used to observe changes in the plasma via emission lines and the supplied electrical parameters (voltage and current). Individual thin films were synthesized using different deposition parameters selected from the previous characterization curves, and their optical properties were characterized via spectroscopic ellipsometry. A correlation between deposition parameters, optical properties, and plasma emission lines was established to optimize silicon nitride deposition.

The application of a helicon plasma source in reactive sputter deposition of tungsten nitride thin films

A reactive helicon wave plasma (HWP) sputtering method is used for the deposition of tungsten nitride (WN x ) thin films. N2 is introduced downstream in the diffusion chamber. The impacts of N2 on the Ar-HWP parameters, such as ion energy distribution functions (IEDFs), electron energy probability functions (EEPFs), electron temperature (T e) and density (n e), are investigated. With the addition of N2, a decrease in electron density is observed due to the dissociative recombination of electrons with The similar IEDF curves of Ar+ and N2 + indicate that the majority of stems from the charge transfer in the collision between Ar+ and N2. Moreover, due to the collisions between electrons and N2 ions, EEPFs show a relatively lower T e with a depletion in the high-energy tail. With increasing negative bias from 50 to 200 V, a phase transition from hexagonal WN to fcc-WN0.5 is observed, together with an increase in the deposition rate and roughness.

Plasma enhanced atomic layer deposition of textured aluminum nitride on platinized substrates for MEMS

We demonstrate an N2 plasma-enhanced process for inducing (0001)-oriented ALD-grown AlN on planar substrates. We evaluate the impact of {111}-textured Pt as a growth template, precursor chemistry, dose time, stress-engineered substrates, inductively coupled plasma conditions for film bombardment during growth, and ALD equipment configurations. The thin film transverse piezoelectric coefficient e31,f determined from measurements on microelectromechanical system cantilevers coated by PEALD AlN is reported to be −0.53 ± 0.03 C/m2. An analysis of the Pt-AlN interface properties based primarily on depth-profile x-ray photoemission spectroscopy and transmission electron microscopy-energy dispersive spectra is presented. Other than the c axis wurtzite (0001) diffraction peak, no other AlN peaks were observed above the detection limits for XRD measurements. The XRD rocking-curve full-width half-maximum of the 0001 peaks was 2.9° omega, which was achieved on {111}-textured Pt. The relative dielectric constant was measured to be 8.1 &amp;lt; K &amp;lt; 8.6, and an average dielectric loss of &amp;lt; 0.01 was observed within the applied electric field range of ±3350 kV/cm at 10 kHz. The leakage current of the textured AlN was quite low at 1.5 × 10−6 A/cm2 over the applied field range of ±1820 kV/cm.

Ultralow‐k Amorphous Boron Nitride Based on Hexagonal Ring Stacking Framework for 300 mm Silicon Technology Platform

AbstractThe implementation of ultralow dielectric constant (k value ≈ 2) materials to reduce signal propagation delay in advanced electronic devices represents a critical challenge in next generations of microelectronics technologies. The introduction of well‐stacked and low polarity molecules that do not compromise film density may lead to improvements and desirable material engineering, as conventional porous SiOx derivatives exhibit detrimental degradation of thermo‐mechanical properties when their k values are further scaled down. This work presents a systematic engineering approach for controlling ultralow‐k amorphous boron nitride (aBN) deposition on 300 mm Si platforms. The results indicate that aBN grown from borazine precursor exhibits ultralow dielectric constant ≈2, high density, excellent mechanical strength, and extended thermodynamic stability. Unintentional boron ion doping during plasma dissociation that may induce artificial reductions of k value on n‐type substrates is alleviated by employing a remote microwave plasma process. Moreover, the adoption of low growth rate processes for ultralow‐k aBN deposition is found to be critical to provide for the superior mechanical strength and high density, and is attributed to the formation of hexagonal ring stacking frameworks. These results pave the way and offer engineering solutions for new ultralow‐k material introduction into future semiconductor manufacturing applications.

Graphene-based deep-ultraviolet photodetectors with ultrahigh responsivity using chemical vapor deposition of hexagonal boron nitride to achieve photogating

This study presents high-responsivity graphene-based deep-ultraviolet (DUV) photodetectors using chemical vapor deposition (CVD)-hexagonal boron nitride (h-BN) photogating. To improve the DUV photoresponse, h-BN was used as a photosensitizer in graphene field-effect transistors (GFETs). The h-BN photosensitizers were synthesized using CVD and then transferred onto a SiO2/Si substrate. The behavior of h-BN irradiated with DUV light was investigated using cathodoluminescence and UV–VIS reflectance. Under 260 nm light, it exhibited a clear photoresponse with an ultrahigh responsivity of 19600 AW-1, which was 460% higher than a GFET device without h-BN photosensitizers. A noise equivalent power of 3.09×10−13 W/Hz1/2 was achieved.

Deposition, microstructure and nanoindentation of multilayer Zr nitride and carbonitride nanostructured coatings

Nitrides, carbides, and carbonitrides of transition metal elements like Zr, W, Ti, etc. are generally employed to produce hard coatings. Zirconium-based hard coatings have shown useful applications in the areas of tribology, biomedicine and electrical due to their high thermal stability, hardness, biocompatibility, good erosion, wear, and corrosion resistance. In this study, we created homogeneous and tenacious nanostructured hard coatings based on Zr with good mechanical properties. The magnetron sputter deposition technique was utilized to coat stainless steel 316L substrates with multilayers of Zr/ZrN and ZrN/ZrCN with individual layer thicknesses of 250 and 500 nm for each coating composition. The deposition conditions were adjusted to create two different coating thicknesses of 2 and 3 µm. The thickness of the coating was confirmed using Calotest and the coatings’ morphology and elemental composition were determined utilizing the atomic force microscope and scanning electron microscope equipped with energy dispersive x-ray spectrometer. Coating thickness and adhesion were measured using cross-sectional samples and XRD was utilized to analyze the coatings structure. Nanoindenter was employed to determine the instrumental nanoindentation hardness and elastic modulus. The influence of coating thickness on tribological behavior was further investigated using the ratio of nanohardness-to-elastic modulus (H/E). No evidence of decohesion was observed at the substrate/coatings interface, and the grains of all the coatings were observed to show columnar growth which were homogeneous, compact and dense. The grains of the ZrN/ZrCN coatings were observed to be denser, finer and more compact compared to those of the Zr/ZrN coatings. Correspondingly, higher hardness, modulus and H/E values were exhibited by ZrN/ZrCN than Zr/ZrN coatings. This suggests that the ZrN/ZrCN coatings are capable of exhibiting better wear resistance and fracture toughness. The coatings developed in this investigation are anticipated to be suitable for applications in tribology due to their excellent hardness and H/E properties.

Area-Selective Deposition of Tantalum Nitride with Polymerizable Monolayers: From Liquid to Vapor Phase Inhibitors

Area-Selective Deposition of Tantalum Nitride with Polymerizable Monolayers: From Liquid to Vapor Phase Inhibitors

Исследование структурно-фазового состояния и механических свойств покрытий ZrCrN, полученных вакуумно-дуговым методом

Introduction. Modern technologies allow the synthesis of nanostructured coatings from multiple chemical elements to combine different physical, mechanical, and chemical properties in one coating. Promising in this respect are coatings formed via layer-by-layer deposition of zirconium and chromium nitrides. The deposition of various chemical elements on various substrates requires separate studies in order to produce high-strength and wear-resistant coatings. The purpose of this work is to study the structural-phase state and mechanical properties of ZrCrN coatings formed by plasma-assisted vacuum arc evaporation. Materials and methods. The investigation is performed on specimens comprising VK8 hard alloy substrates with zirconium and chromium nitride coatings as well as with multilayer ZrCrN coatings. The methods used are confocal laser scanning microscopy, X-ray diffraction analysis, high-resolution scanning electron microscopy, nanoindentation, and scratching. Results and discussion. The experimental results obtained showed that the mode of multilayer ZrCrN coating evaporation greatly affects the structure, morphology, surface roughness, and mechanical properties of the coatings. In particular, by varying the substrate rotation speed during coating deposition it is possible to control the deposition time of each coating layer and thereby modify the layer properties. Conclusions. The investigation results showed that variation of the evaporation conditions allows one to obtain a ZrCrN coating with a high nanohardness of 45 GPa on a VK8 alloy substrate. Analysis of mechanical test results indicate good adhesion between the studied coatings and the substrate. Scratch tests revealed that fracture of CrN and ZrN coatings occurs by the cohesive mechanism, and the surface of ZrCrN coatings exhibits uniform scratches without any signs of fracture. Based on the results obtained, ZrCrN-2…ZrCrN-4 coatings can be recommended for use as hard and wear-resistant coatings.

Comparative Analysis over Tribology Characterization of TiAlN and TiAlSiN PVD Coating on Plasma Nitride Alloy 20

The nickel–iron–chromium (alloy 20) is enriching by hybrid surface treatment through plasma nitride (PN) and physical vapor deposition (PVD) process. The plasma nitriding process takes 12 h at 500 °C. Potentiodynamic testing is used to characterize the corrosion performance of the treated material, followed by morphological analysis of the exposed surface; XRD, EDX, SEM, hardness, and tensile testing are used to investigate appropriate coating properties. Plasma nitride and hybrid PVD nickel–iron–chromium alloys exhibit perlite (γ + α′) phases and martensite (γ + α) phases, respectively. The martensite microstructure ensures superior tensile strength and hardness. The pin-on-disc tribometer test proposes to analyze friction and hard-faced behavior in the dry sliding position. The inclusion of Si improves the adherent oxide film, resulting in a low wear rate in TiAlSiN alloy 20. Due to the presence of the passive film, TiAlSiN alloy 20 exposes the most passive region to attain better corrosion resistance.Graphical Abstract

Flow-modulated deposition of sp2-boron nitride using diborane and ammonia on chemomechanically polished (0001) 4H-SiC substrates

Nanocrystalline sp2-BN thin films have been grown on (0001) 4H-SiC substrates at 1030 °C via continuous flow and discontinuous flow-modulated chemical vapor deposition techniques using diborane (B2H6) and ammonia (NH3) as the B and N sources, respectively. The latter technique enabled observations of both the effect of hydrogen purge steps between precursor injections and the length of injection times for B2H6 on the stoichiometry and microstructure of the films. Stoichiometric BN was achieved in all films grown continuously within the N/B gas phase ratio range of 20–200; this was not observed for the discontinuously grown films unless both the B2H6 flow rate and the injection time were minimized. Cross-sectional transmission electron microscopy of films grown both continuously and discontinuously at N/B = 200 and using short B2H6 injection times relative to that of NH3 for the latter process route revealed the initial growth of ∼4 nm thick partially ordered sp2-BN layers. A transition zone then formed containing randomly oriented polycrystalline grains. Excess B incorporated into the discontinuously grown films during long B2H6 injection times resulted in single layer mixtures of amorphous and sp2-BN without any observed ordering.

Influence of the Titanium Nitride Deposition Duration during Vacuum Ion-Plasma Treatment on the Resistance of Coatings in a Hydrogen Atmosphere

In this work, the insulating properties of nitride coatings against the hydrogen penetration into semi-finished or finished products made of VT6 titanium alloy during hydrogenation annealing have been studied. It has been established that an increase of the duration of titanium nitride deposition for more than 30 minutes leads to the formation of pores and cracks in the coating and, as a consequence, to a decrease in the «protective» properties of such coating. It is shown that during linear gradient structure creation, the nitride coating effectively “protects” alloy from penetration of up to 0.5 wt%. of hydrogen.