Growth Mechanism Of Films Research Articles

Orientation-dependent structural properties during growth and growth mechanism of CoO films

The orientation-dependent local structural properties of CoO films on sapphire substrates during growth were investigated through linearly-polarized extended X-ray absorption fine structure (EXAFS) measurements. Specifically, CoO(111) and (100) crystals with a rock-salt structure (Fm3m) were epitaxially grown on α-Al2O3(0001) and (101¯2) substrates, respectively, at 700℃ using a radio-frequency sputtering system. The local structural properties of CoO films in the in-plane and out-of-plane orientations were quantitatively determined using linearly-polarized EXAFS at the Co K-edge during growth. The EXAFS analysis revealed that during the initial stages of growth, the local structural properties exhibit significant differences compared to thick films, with short atomic distances and large (small) Debye-Waller factors observed in the out-of-plane (in-plane) orientations. The local structural strain mostly diminished when approximately 20 CoO layers accumulated on the substrate. Density functional theory (DFT) calculations further supported these findings by confirming that cobalt atoms initially form stable bonds with the sapphire surface, leading to the simultaneous growth of oxygen and cobalt layers in a coordinated manner through layer-by-layer growth.

Multivariate growth analysis on D019–phase Mn3Ga kagome–based topological antiferromagnets

The combination of antiferromagnetism and topological properties in Mn3X (X = Sn,Ge,Ga) offers a unique platform to explore novel spin-dependent phenomena and develop innovative spintronic devices. Here, we have systematically investigated the phase transition of Mn3Ga thin films on SiO2(001)/Si substrates under various growth parameters such as seeding layer structure, annealing conditions, and film thickness. The relatively thick Mn3Ga films grown with Ru seeding exhibit a variety of polycrystalline hexagonal phases, including (002), and (201). The addition of a Ta layer to the conventional Ru seeding layer promotes the formation of nearly single-crystal antiferromagnetic (AF) Mn3Ga(002) phase from the relatively thin Mn3Ga films after annealing at 773 K. The investigation of the growth mechanism of Mn3Ga polycrystalline thin films provides a reference strategy for exploring Mn-based AF spintronic devices.

Sputtering of (111) highly-oriented nanotwinned Ag on polycrystalline Si3N4 substrates for high-power electronic packaging

Nanotwinned silver (NT-Ag) exhibits excellent mechanical and electrical properties, attributed to its high-density and (111) highly-oriented twinning structure in nanoscale. Therefore, it has recently drawn much attention in the field of electronic packaging, where it can be utilized as interconnection or metallization materials. However, it has been a critical challenge to fabricate the high-density and highly-oriented NT-Ag onto polycrystalline ceramic substrates, whose crystal structure does not support the epitaxial growth of NT-Ag films. In the current work, a high-density and highly-oriented NT-Ag film has been fabricated onto a polycrystalline ceramic substrate, i.e., NT-Ag on silicon nitride (NT-Ag@Si3N4), using the magnetron sputtering method. As results, a close-packed arrangement of high-density NT-Ag has been observed within columnar grains aligned along its growth direction, whereas the nanoindentation hardness of the NT-Ag film reached 1.82 GPa, with an electrical resistivity of 2.06 μΩ‧cm. Moreover, this study has discussed and explained the growth kinetics and mechanism of NT-Ag films, by controlling magnetron sputtering process parameters, such as sputtering power and argon flow rate. Additionally, the differences in the growth mechanism of NT-Ag on (100) Si and polycrystalline Si3N4 have also been investigated. With its superior material properties, NT-Ag@Si3N4 holds great promise in the applications of advanced packaging technology for high-power electronics.

Effect of substrate temperature on the growth mechanism of FeSe superconducting films

Abstract Among all the iron-based superconductors (IBSs), Fe-chalcogenides (Fe-Ch) possess the advan tages of simple structure, non-toxicity, low anisotropy and the potential for high-field applications.One of the most effective methods for preparing Fe-Ch films is pulsed laser deposition (PLD). However, high quality film growth is challenged by the significant volatility difference between the iron
and chalcogens (S, Se, Te), which affects stoichiometric transfer from target to substrate and subsequently impacts superconductivity. Currently, there is limited research on the correlation between the growth mechanism and preparation conditions of Fe-Ch films, particularly in explaining chalcogen volatility during deposition. Technically, PLD offers various adjustable parameters, among
which the substrate temperature (Ts) is the most critical one affecting film quality. It governs particle behavior on the substrate including adsorption, diffusion, bonding reactions, crystallization processes while also strongly affecting volatilization rates. In this study, we fabricated a series of FeSe films using PLD at different Ts ranging from 25 ℃ to 750 ℃.We reveal in detail the impact of
competitive processes between Se volatilization and reactive crystallization of Fe/Se on film quality. The optimal film was obtained at Ts=500 ℃ with a composition ratio of Fe1.01Se. We also investigate the correlations between Ts and film crystallinity, surface morphology, along with their influence on superconductivity. Additionally, the pinning mechanism in FeSe film grown at the
optimal Ts was briefly analyzed. Our results provide reliable experimental evidence regarding the growth mechanism of FeSe films while revealing comprehensive insights into how Ts affects both film quality and performance.

Investigating the Influence of the Substrate Temperature and the Organic Precursor on the Mechanical Properties of Low‐Pressure Plasma Polymer Films

ABSTRACTThis work aims to investigate the influence of the substrate temperature on low‐pressure plasma polymerization processes. Emphasis is placed on the mechanical properties and growth mechanism of the plasma polymer films (PPFs). For this purpose, two precursors are considered, differing only by their unsaturation degree: 2‐propen‐1‐ol (CH2═CH–CH2–OH) and propan‐1‐ol (CH3–CH2–CH2–OH). Although propan‐1‐ol‐based PPFs behave like hard elastic solids, 2‐propen‐1‐ol‐based coatings evolve from a liquid film to an elastic solid on increasing the substrate temperature. This behavior is understood considering the evolution of the glass transition temperature of PPFs. The latter is correlated with the cross‐linking degree of the polymeric network governed by the energy density of bombarding ions on the growing film.

Study on growth kinetics of passivation film of Ti-6Al-3Nb-2Zr-1Mo alloy Based on point defect model

This study aims to explore the passivation behavior and growth mechanism of the Ti-6Al-3Nb-2Zr-1Mo alloy in an oxygen-free environment, taking into account various film-forming potentials and solution pH levels in the process. The point defect model is employed to study the growth mechanism of the passivation film. A film-forming potential is selected within the stable passivation region for polarization, followed by conventional electrochemical tests, Localized Electrochemical Impedance Spectroscopy, X-ray photoelectron spectroscopy characterization, and Glow Discharge Optical Emission Spectrometry. Experimental findings indicate that the passivation film on the Ti-6Al-3Nb-2Zr-1Mo alloy surface demonstrates characteristics of an n-type semiconductor. Increasing the film-forming potential leads to a decrease in the donor point defect density. Meanwhile, elevating the pH of the solution decreases the oxygen vacancy diffusion coefficient from 7.8 × 1019 to 4.3 × 1019, thus improving the corrosion resistance of the passivation film.

Growth mechanism of Ge2Sb2Te5 thin films by atomic layer deposition supercycles of GeTe and SbTe

The film with a composition close to Ge2Sb2Te5 was fabricated by the supercycle atomic layer deposition (ALD) of GeTe and SbTe, followed by tellurization annealing. Supercycle processes are widely used for thin film deposition of multicomponent materials and often exhibit non-ideal growth behavior. Since only in situ analysis can reveal the substrate-dependent growth behavior, we used in situ quartz crystal microbalance (QCM) to study the growth mechanism during ALD supercycle processes at 85 °C. GeTe grown on SbTe was more Te-deficient than continuously grown GeTe film. As a result, more Te-deficient Ge-Sb-Te films were formed than expected. By annealing in a Te ambient at 250 °C, the Te-deficient Ge-Sb-Te film was converted to the Ge0.23Sb0.23Te0.54 close to Ge2Sb2Te5 film, which had a high density equivalent to 95 % of the FCC structure of Ge2Sb2Te5. The film showed excellent conformality and uniform composition in a trench pattern, suggesting a uniform crystallization temperature of 118 °C at all locations.

Growth Conditions and Interfacial Misfit Array in SnTe (111) Films Grown on InP (111)A Substrates by Molecular Beam Epitaxy.

Tin telluride (SnTe) is an IV-VI semiconductor with a topological crystalline insulator band structure, high thermoelectric performance, and in-plane ferroelectricity. Despite its many applications, there has been little work focused on understanding the growth mechanisms of SnTe thin films. In this manuscript, we investigate the molecular beam epitaxy synthesis of SnTe (111) thin films on InP (111)A substrates. We explore the effect of substrate temperature, Te/Sn flux ratio, and growth rate on the film quality. Using a substrate temperature of 340 °C, a Te/Sn flux ratio of 3, and a growth rate of 0.48 Å/s, fully coalesced and single crystalline SnTe (111) epitaxial layers with X-ray rocking curve full-width-at-half-maxima of 0.09° and root-mean-square surface roughness as low as 0.2 nm have been obtained. Despite the 7.5% lattice mismatch between the SnTe (111) film and the InP (111)A substrate, reciprocal space mapping indicates that the 15 nm SnTe layer is fully relaxed. We show that a periodic interfacial misfit (IMF) dislocation array forms at the SnTe/InP heterointerface, where each IMF dislocation is separated by 14 InP lattice sites/13 SnTe lattice sites, providing rapid strain relaxation and yielding the high quality SnTe layer. This is the first report of an IMF array forming in a rock-salt on zinc-blende material system and at an IV-VI on III-V heterointerface, and highlights the potential for SnTe as a buffer layer for epitaxial telluride film growth. This work represents an important milestone in enabling the heterointegration between IV-VI and III-V semiconductors to create multifunctional devices.

Uniform Sb doping of ZnO films with controllable morphology and enhanced optical property

In order to provide an effective and reliable approach to solving the difficulties in p-type modification of ZnO nanomaterials, in this work, we successfully synthesized ZnO films with uniform antimony distribution through low temperature aqueous growth method. The growth quality and dopant distribution of Sb-doped ZnO (SZO) films were evaluated by high-resolution micro-structural characterizations, and the growth mechanism for SZO films with various doping concentrations was discussed and revealed. Uniform and dispersive Sb distribution within SZO films contributed to the light transmittance of SZO films. The blue-shifted UV emission accompanied with weak visible light emission of SZO films were observed in room-temperature photoluminescent (PL) spectra, the rare yellow-red light emission and XPS results confirmed the existence of SbZn-related complex defects. This type of SZO films is competitive and promising for serving as the highly photo-conductive and photo-sensitive ZnO-based nanomaterials. And SZO films could be served as the basis for realizing the purpose of p-type modification with high efficiency and excellent stability.

Formation and growth mechanism of thin Cu6Sn5 films in Sn/Cu and Sn-0.1AlN/Cu structures using laser heating

PurposeThe purpose of this study is the formation and growth of nanoscale intermetallic compounds (IMCs) when laser is used as a heat source to form solder joints.Design/methodology/approachThis study investigates the Sn/Cu and Sn-0.1AlN/Cu structure using laser soldering under different laser power: (200, 225 and 250 W) and heating time: (2, 3 and 4 s).FindingsThe results show clearly that the formation of nano-Cu6Sn5 films is feasible in the laser heating (200 W and 2 s) with Sn/Cu and Sn-0.1AlN/Cu system. The nano-Cu6Sn5 films with thickness of 500 nm and grains with 700 nm are generally parallel to the Cu surface with Sn-0.1AlN. Both IMC films thickness of Sn/Cu and Sn-0.1AlN/Cu solder joints gradually increased from 524.2 to 2025.8 nm as the laser heating time and the laser power extended. Nevertheless, doping AlN nanoparticles can slow down the growth rate of Cu6Sn5 films in Sn solder joints due to its adsorption.Originality/valueThe formation of nano-Cu6Sn5 films using laser heating can provide a new method for nanofilm development to realize the metallurgical interconnection in electronic packaging.

Growth mechanism of HfO2 film on H-terminated Si (100) surface from atomic layer deposition process using tetrakis(ethylmethylamino)hafnium

The deposition of HfO2 on H-terminated Si (100) surfaces presents both interest and challenges due to the complexity of the surface reaction mechanisms. Previous experimental studies reported conflicting results regarding the formation of interfacial layers and the presence of incubation periods during the initial cycles of the HfO2 atomic layer deposition (ALD) process. In this study, we provide a detailed analysis of the surface reaction mechanism of HfO2 ALD on H-terminated Si (100) surfaces using tetrakis(ethylmethylamino)hafnium (TEMAH) and water. Our findings demonstrate that TEMAH chemisorbs onto the H-terminated Si (100) surface through the formation of two N-Si interfacial bonds. Additionally, the remaining ligands of the adsorbed Hf precursor are efficiently removed through hydroxylation during the water pulse, with low energy barriers of +25.9 to +30.0 kJ/mol. Furthermore, the N-Si interfacial bonds can be broken, allowing for the formation of Hf-O-Si interfacial bonds during either the water pulse or post-deposition processes. This work provides valuable insights into the surface reactions of HfO2 ALD and explains the varied interfacial bonding and incubation periods observed in prior studies.

First-Principles computation-driven mechanism study of tungsten growth on alumina surfaces with TiN nano-islands

Strong comprehension of the tungsten film deposition process on Al2O3 substrate with TiN adhesion layer is essential to achieve high quality metal gate, but the fundamental mechanism of this process is yet to be fully understood. This study employs first-principles density functional theory (DFT) calculations to explore the mechanisms of tungsten film growth on alumina surfaces while focusing on amorphous/α-Al2O3 and interfaces with TiN nano-islands. Tungsten atoms are strongly bonded on the Al2O3/TiN interface compared to their bonding on the Al2O3 or TiN surface, regardless of the crystallinity of Al2O3. Moreover, amorphous Al2O3 surfaces exhibit stronger adsorption energies and present higher diffusion barriers for tungsten atoms compared to their crystalline counterparts, α-Al2O3, and TiN surfaces, which were also confirmed by electronic structure analysis. This enhanced adhesion on amorphous substrates suggests a potential pathway through which improve the step coverage and uniformity of tungsten thin films while addressing common issues such as void formation and non-uniform layering in high-aspect-ratio structures. Post-deposition annealing can help create crystalline tungsten films with superior conductivity. The insights gained from this work offer a computational perspective on the atomic-level interactions governing tungsten deposition, and they are expected to help producing high-quality thin films in semiconductor technologies.

Wet Chemical Synthesis of AlxGa1−xAs Nanostructures: Investigation of Properties and Growth Mechanisms

This study focuses on the wet chemical synthesis of AlxGa1−xAs nanostructures, highlighting how different deposition conditions affect the film morphology and material properties. Electrochemical etching was used to texture GaAs substrates, enhancing mechanical adhesion and chemical bonding. Various deposition regimes, including voltage switching, gradual voltage increase, and pulsed voltage, were applied to explore their impact on the film growth mechanisms. SEM analysis revealed distinct morphologies, EDX confirmed variations in aluminum content, Raman spectroscopy detected structural disorders, and XRD analysis demonstrated peak position shifts. The findings emphasize the versatility and cost-effectiveness of wet electrochemical methods for fabricating high-quality AlxGa1−xAs films with tailored properties, showing potential for optoelectronic devices, high-efficiency solar cells, and other advanced semiconductor applications.

Optimizing Crystal Orientation and Defect Mitigation in Antimony Selenide Thin-Film Solar Cells through Buffer Layer Energy Band Adjustment.

Antimony selenide (Sb2Se3) has sparked significant interest in high-efficiency photovoltaic applications due to its advantageous material and optoelectronic properties. In recent years, there has been considerable development in this area. Nonetheless, defects and suboptimal [hk0] crystal orientation expressively limit further device efficiency enhancement. This study used Zinc (Zn) to adjust the interfacial energy band and strengthen carrier transport. For the first time, it is discovered that the diffusion of Zn in the cadmium sulfide (CdS) buffer layer can affect the crystalline orientation of the Sb2Se3 thin films in the superstrate structure. The effect of Zn diffusion on the morphology of Sb2Se3 thin films with CdxZn1-xS buffer layer has been investigated in detail. Additionally, Zn doping promotes forming Sb2Se3 thin films with the desired [hk1] orientation, resulting in denser and larger grain sizes which will eventually regulate the defect density. Finally, based on the energy band structure and high-quality Sb2Se3 thin films, this study achieves a champion power conversion efficiency (PCE) of 8.76%, with a VOC of 458mV, a JSC of 28.13mA cm-2, and an FF of 67.85%. Overall, this study explores the growth mechanism of Sb2Se3 thin films, which can lead to further improvements in the efficiency of Sb2Se3 solar cells.

Microstructural and Electrochemical Study: Pitting Corrosion Mechanism on A390 Al-Si Alloy and Ce-Mo Treatment as a Better Corrosion Protection.

Sulfuric acid anodizing assisted by a hydrothermal sealing with inhibitors [Ce3+-Mo6+] was used to prevent pitting corrosion on spray-deposited hypereutectic Al-Si alloy (A390). An investigation concerning the evaluation of pitting corrosion resistance on the anodic oxide thin film with ions incorporated was carried out in NaCl solution using electrochemical measurements (i.e., potentiodynamic polarization and electrochemical impedance spectroscopy, EIS). The influence of Si phase morphology and size on the growth mechanism of an anodic oxide film was characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The results were then compared with those for its equivalent IM390 alloy (Al-17Si-4.5Cu-0.6Mg) produced through a conventional process ingot metallurgy, IM. The electrochemical findings indicate that sulfuric acid anodizing followed by a simple hot water sealing treatment was ineffective. In this manner, an intense attack was localized by pitting corrosion that occurred on the anodic oxide film in less than three days, as denoted by characteristic changes in the EIS spectra at the lowest frequencies. Improved results were achieved for Ce-Mo surface modification, which can provide better corrosion resistance on the aluminum alloys because no signs of pits were observed during the corrosion testing.

Preparation and growth mechanism of nonpolar, semipolar and polar ZnO films: Correlation of preferred orientation, defects and optical properties

In the study, ZnO films with different preferred orientations were controllably prepared by using NH3·H2O to modulate the pH0 of chemical bath deposition. The samples were all characterised by field emission scanning electron microscopy (FESEM), atomic force microscopy (AFM), X-ray diffraction (XRD), ultraviolet-visible spectrophotometry (UV–VIS), X-ray photoemission spectroscopy (XPS) and photoluminescence (PL). The results show that ZnO films with polar, semipolar and nonpolar preferred orientations can be synthesised in a controlled manner by varying the pH0. Meanwhile, the influence of NH3·H2O concentration on the growth process of ZnO films is investigated in detail, and the relationship between the preferred orientation and optical properties is preliminarily discussed. At pH0= 7.32, the films exhibited semipolar (101) preferred orientation, the highest optical transmittance (89.15 %), and the highest concentration of Zni in the films. This study provides a method for the controlled synthesis of ZnO films with polar, semipolar and nonpolar preferred orientations and offers new possibilities for ZnO-based transparent semiconductor devices.

Epitaxial Growth of GaN Films on Chemical-Vapor-Deposited 2D MoS2 Layers by Plasma-Assisted Molecular Beam Epitaxy.

The van der Waals epitaxy of wafer-scale GaN on 2D MoS2 and the integration of GaN/MoS2 heterostructures were investigated in this report. GaN films have been successfully grown on 2D MoS2 layers using three different Ga fluxes via a plasma-assisted molecular beam epitaxy (PA-MBE) system. The substrate for the growth was a few-layer 2D MoS2 deposited on sapphire using chemical vapor deposition (CVD). Three different Ga fluxes were provided by the gallium source of the K-cell at temperatures of 825, 875, and 925 °C, respectively. After the growth, RHEED, HR-XRD, and TEM were conducted to study the crystal structure of GaN films. The surface morphology was obtained using FE-SEM and AFM. Chemical composition was confirmed by XPS and EDS. Raman and PL spectra were carried out to investigate the optical properties of GaN films. According to the characterizations of GaN films, the van der Waals epitaxial growth mechanism of GaN films changed from 3D to 2D with the increase in Ga flux, provided by higher temperatures of the K-cell. GaN films grown at 750 °C for 3 h with a K-cell temperature of 925 °C demonstrated the greatest crystal quality, chemical composition, and optical properties. The heterostructure of 3D GaN on 2D MoS2 was integrated successfully using the low-temperature PA-MBE technique, which could be applied to novel electronics and optoelectronics.

Effect of substrate temperature on growth mechanism and properties of PEALD-MgO dielectric films for amorphous-IGZO TFTs

Magnesium oxide (MgO) films have been prepared by plasma enhanced atomic layer deposition with bis(cyclopentadienyl)magnesium precursor and oxygen plasma reactant at substrate temperature between 150 °C and 450 °C. The structural, morphological, optical, and chemical properties of the prepared MgO films were studied by spectroscopic ellipsometer, grazing incidence X-ray diffraction (GIXRD), field emission scanning electron microscopy, atomic force microscopy, X-ray photoelectron spectroscopy (XPS). The electrical property of MgO film was obtained by performing capacitance-voltage measurement on the Al/MgO/Si structures. The experiment result shows that growth rate of MgO film decreases with the deposition temperature increased. GIXRD analysis presented that MgO films are cubic with predominantly (220) crystal orientation. XPS analysis shows that ratio of Mg/O is highest in MgO film prepared at 350 °C. To illustrate the possible applications of MgO film as a gate dielectric in thin film transistor (TFT), indium‑gallium‑zinc oxide (IGZO) was used as channel layer. The optimized IGZO/MgO TFT showed an electron mobility of 1.63 cm2/Vs, an on/off current ratio of 106, and a subthreshold swing of 0.50 V/decade at a low operation voltage of −0.11 V.

Unveiling the growth mechanism of FeSeTe films by pulsed laser deposition technique

The superconductivity of FeSeTe films, deposited by the pulsed laser deposition (PLD), is extremely sensitive to the preparation conditions. Hence, it is necessary to study the growth mechanism and reveal the key factors affecting the superconductivity of FeSeTe films. Among all the preparation conditions, the substrate temperature ( Ts ) is one of the most critical one because it can alter the diffusion and nucleation of deposited atoms, as well as subsequent secondary volatilization. In this study, we prepared a series of FeSeTe films deposited on CaF2 substrates with Ts ranging from 25 ∘C to 700 ∘C. It is found that the growth mechanism of the FeSeTe films deposited at different Ts is determined by the competition between crystallization and volatilization, and the Ts can serve as an effective means to regulate the (Se+Te):Fe ratio of the FeSeTe films. The superconductivity of the FeSeTe films is co-modulated by the crystallinity and composition. In addition, the Ts can greatly affect the pinning mechanism of the FeSeTe films by introducing the fine nonstoichiometric particles, local chemical inhomogeneity and planar defects. This work facilitates the further performance improvement and practical applications of FeSeTe superconducting films, and is of reference for the FeSeTe film prepared by other deposition methods.

Polydopamine films: Versatile but interface-dependent coatings

Abstract Polydopamine coatings have been shown to allow to coat almost all materials with conformal films having a tunable thickness from a few up to more than 100 nm (and even more in some specific cases). These films are able to reduce metal cations, to be modified with many chemical moieties and advent hence as a “Holy Grail” in surface chemistry with an impressive amount of applicative papers published since 2007. However, the broad application field and ease of deposition from aqueous solutions hidden the complexity of the deposition mechanism(s). The discovery that polydopamine (PDA) films also form at air/water interfaces (in the absence of stirring or in stirring dependent manner) to yield membranes with physicochemical properties different than PDA films deposited at solid/water interfaces highlighted for the first time that the nature of the interfaces plays a major role in the PDA film growth mechanism and in the film properties. More recent research allowed to show that the surface chemistry of the used solid substrate modifies the composition of the thin deposited PDA film during the early stages of the deposition process with further deposition yielding to an almost substrate-independent PDA film. It is the aim of this review to describe complex surface effects occurring in PDA deposition and hence to complement other reviews which described the complexity of the chemistry yielding to PDA coatings.