Film Processing Research Articles

Thickness dependence and crystallization properties of amorphous GeTe thin films on silicon dioxide

Radio frequency magnetron sputtering was used to prepare the amorphous GeTe thin films on silicon dioxide and the thickness effects on the crystallization behavior were investigated. With the film thickness reducing, the crystallization temperature, crystallization activation energy, amorphous and crystalline resistance increase remarkably, indicating the great improvement in thermal stability and power consumption. Ozawa’s model was used to estimate the crystallization kinetics of GeTe thin films, it shows that nucleation and grain growth occur simultaneously, and grain growth dominates ultimately. XRD analysis demonstrated that the grain size can be reduced and the crystallization process of GeTe thin film can be inhibited with the film thickness decreasing. Furthermore, the thinner film has smaller resistance drift index and surface roughness, which are beneficial to improve the reliability of storage device. T-type phase change memory devices based on 25 nm GeTe thin film were fabricated by 0.13 μm CMOS technology, and the current–voltage and resistance-voltage characteristics demonstrate the excellent electrical performance, including the fast resistance switching between SET and RESET processes, low threshold current and voltage. All the results proved the strong dependency relationships between the crystallization properties and film thickness of GeTe thin film, which paves the way for developing high-density phase change memory in the fields of big data and artificial intelligence.

Transmedia skill derived from the process of converting films into educational games with augmented reality and artificial intelligence

Transmedia skill, derived from the process of converting films into educational games using augmented reality and artificial intelligence, involves employing various languages and mediums to adapt an original narrative to another format. This transmedia practice presents an opportunity to cultivate diverse skills in teacher training by transforming film narratives into educational games with Augmented Reality (AR) and Artificial Intelligence (AI). Moreover, these educational games enable student engagement in missions or challenges, enhancing their engagement with educational activities. Thus, this research stems from an Innovation project implemented in the Degree in Early Childhood Education (N=77) with two groups of university students who developed 24 educational games in physical and digital formats. The objectives are: 1) to compare the transmedia process adopted by both groups when converting children's animation films into games, some in digital format and others combining physical and digital resources; and 2) to analyze their transmedia skill reflected in the games developed. The methodology adopted is non-experimental empirical, with a descriptive and comparative nature. Two instruments were designed and validated, one to analyze the transmedia process followed in each case and another to ascertain the level of transmedia skill of the university students. The results reveal that both groups chose different creative approaches to gamify the films, expanding their stories by leveraging the potential of AR and AI to create interactive characters and settings. From this, their transmedia capability could be inferred. Thus, the use of digital applications to collaboratively design games—utilizing film narratives—represented an innovation in their training, holistically enhancing various skills. In conclusion, this experience presents an opportunity to increase the transmedia skills of future educators.

Crystallographic orientation dependence in creep deformation of micron-thick silicon films for 3-D microstructures

In this study, the steady-state creep deformation properties of 5 μm-thick single crystal silicon (Si) films at elevated temperatures were investigated using punch creep-forming tests for the design of three-dimensional (3-D) microstructured MEMS. The relationship between the creep strain rate and stress of the Si films with {100}, {110}, and {111} planes at temperatures of 1223–1323 K was derived using finite element analysis following punch creep-forming tests, and a power-law creep constitutive equation for Si films was determined. The steady-state creep properties of the Si film samples varied clearly with crystallographic orientations. Among the three crystallographic orientations, the creep strain rate of the micron-thick Si films was the fastest for the {011} plane, followed by the {111} and {001} planes, in the applied stress range of 110 MPa to 220 MPa. This is consistent with the increasing order of magnitude of the thermal activation energy. The crystallographic orientation dependence of the steady-state creep properties of Si films is discussed based on the mobility of dislocation gliding per unit lattice and scanning electron microscope observations. The sample-size dependence of the creep strain rate of Si with the {001} plane was clearly observed between the micron- and millimeter-thick samples, which was attributed to the difference in the frequency factor of the power-law creep. However, the thermal-activation energy remained constant. This study successfully revealed the steady-state creep properties of Si films and provided useful engineering data for the design of 3-D Si-MEMS fabrication by the plastic processing of Si films.

Low-temperature processing of high-performance transparent ultra-thin ZrAlOx hybrid dielectric films via solution self-combustion synthesis and application in TFTs

In the realm of electronic applications, there is a pronounced interest in developing high-performance metal oxides via solution processes. Traditional sol-gel techniques, however, are constrained by their reliance on high thermal processing conditions. This study presents a novel approach for fabricating ZrAlOx hybrid dielectric thin films at low temperature utilizing a solution self-combustion process, which involves the coordination of Zr and Al salts with oxidizer and fuel ligands. Thermal analysis of the ZrAlOx precursors indicated that self-combustion occurs at approximately 180 °C, supplying the necessary internal energy to facilitate the formation of metal oxides. This internal energy enables both the conversion of precursors and the elimination of organic impurities with reduced external energy demand, significantly lowering the required annealing temperature. Additionally, the impact of composition ratio of oxidizer (zirconium nitrate) to fuel (aluminum acetylacetonate) was investigated. Results demonstrated that an equivalent ratio of oxidizer to fuel produced the most vigorous self-combustion reaction, thus generating the maximal internal energy needed to compensate for the formation energies of the M-O-M structure. At a low annealing temperature of 180 °C, the resultant amorphous ZrAlOx thin films, synthesized under the stoichiometric condition, displayed the dense, smooth, and pore-free morphology with an ultra-thin thickness of only 11.6 nm. MIM device incorporating this as the dielectric layer exhibited electrical properties comparable to that achieved with expensive vacuum deposition techniques, including low leakage current density of 2.81×10−8 A/cm2 at 1 MV/cm, high capacitance density of 1133 nF/cm2 at 1 kHz, and substantial relative dielectric constant of 14.71. Finally, the high-performance TFT utilizing ZrAlOx dielectric was achieved, demonstrating high mobility of 33.05 cm²/Vs, Ion/Ioff of 5.10×105, and low-voltage operational characteristics with Vth of only 0.21 V. Therefore, the solution self-combustion synthesis method delineated in this study offers promising potential for utilization in the burgeoning fields of flexible and stretchable electronics.

Influence of oxygen content on fatigue crack growth behavior of FGH96 superalloys

The fatigue crack growth (FCG) mechanism of FGH96 superalloys influenced by oxygen (O) was investigated in terms of grain structure and phase composition. The results reveal that the thinner powder oxide film process facilitates easier dissolution, and thus the fewer undissolved oxides as well as the movement of high-angle grain boundaries promote the generation of a uniform distributed small grains (SGs) within both the prior particle boundaries (PPB) interface and powder interior in the alloy with O content of 140 ppm. In contrast, the large number of undissolved oxide particles provides more recrystallization sites and thus the SGs clusters aggregate at the PPB interface in the alloy with O content of 340 ppm during sintering. A homogeneous distribution of SGs induces the uniform deformation of the alloy and thus stimulates the transgranular fracture of the coarse grains in alloy with O content of 140 ppm, in favor of a higher fatigue life. On the contrary, in the alloy with O content of 340 ppm, the SGs clusters forming on PPB interface results to the strain concentration at PPB, leading to the PPB fractured morphology and a serious reduction of the fatigue life. This study reveals that the generation of SGs is responsible for the FCG behavior and failure mechanism of the alloys, and suggests that regulating the uniform distribution of SGs or reducing the number of SGs during sintering plays an important role in improving the fatigue properties of powder metallurgy superalloys.

An Optimized Ultrasonic Spray Pyrolysis Device for The Production of Metal Oxide Films and Their Morfology

In this work, we developed an optimized ultrasonic spray pyrolysis device for obtaining metal oxide films. The key benefit of this facility lies in its cost-effectiveness and its ability to consistently coat extensive surfaces without sacrificing the integrity of the semi-conductive films, thus streamlining the manufacturing process of semiconductor films. The resulting films exhibit the following attributes: the thickness of the deposited layer is approximately 400 nm, while the diameters of ZnO1-xSx nanocrystals range from 50 to 200 nm, oriented perpendicular to the crystallographic orientation (111). In the production of nanorods, the average height is estimated to be approximately 30-50 nm, with a density of 2.9×10¹¹ cm⁻² being indicated.

A versatile steel belt casting equipment for in situ synchrotron radiation x-ray scattering measurement of polymer films.

A steel belt casting equipment, weighing approximately ∼6-7 tons and measuring ∼5m in length, has been designed and developed for simulating the industrial processing of polymer films and being combined with synchrotron radiation in situ x-ray scattering measurements. Through modification of its modules, it is feasible to implement two distinct film casting modes, namely the wet and the dry casting processes. The speed of a steel belt can span from 0.5 to 8 m/min. The highest experimental temperature and drying wind speed are 300 °C and 6m/s, respectively. All film casting parameters, such as extrusion speed, distance between die and steel belt, casting speed, temperature, and wind speed, can be adjusted independently. Especially, the control accuracy of the temperature and casting rate can reach ±0.1 °C and ±0.01 m/min, respectively. The feasibility of this equipment has been validated through in situ x-ray scattering tests at the BL10U1 industrial beamline of the Shanghai synchrotron radiation facility. With the assistance of this equipment, the understanding of the physical mechanism behind the film casting process should be improved so that the development of advanced functional polymer films.

Suppressed Defects by Functional Thermally Cross-Linked Fullerene for High-Efficiency Tin-Lead Perovskite Solar Cells.

Mixed tin-lead (Sn-Pb) perovskites have attracted the attention of the community due to their narrow bandgap, ideal for photovoltaic applications, especially tandem solar cells. However, the oxidation and rapid crystallization of Sn2+ and the interfacial traps hinder their development. Here, cross-linkable [6,6]-phenyl-C61-butyric styryl dendron ester (C-PCBSD) is introduced during the quenching step of perovskite thin film processing to suppress the generation of surface defects at the electron transport layer interface and improve the bulk crystallinity. The C-PCBSD has strong coordination ability with Sn2+ and Pb2+ perovskite precursors, which retards the crystallization process, suppresses the oxidation of Sn2+, and improves the perovskite bulk and surface crystallinity, yielding films with reduced nonradiative recombination and enhanced interface charge extraction. Besides, the C-PCBSD network deposited on the perovskite surface displays superior hydrophobicity and oxygen resistance. Consequently, the devices with C-PCBSD obtain PCEs of up to 23.4% and retained 97% of initial efficiency after 2000h of storage in a N2 atmosphere.

Enhanced Marangoni flow to fabricate uniform and porous SiO2 films: Toward superior high transparency, antifogging, and self- cleaning properties

Fogging on transparent substrate greatly impacts transmittance, causing inconvenience and potential hazards. Increasing surface roughness to enhance hydrophilicity often reduces transmittance. Here, by enhancing the Marangoni flow to inhibit the coffee-ring effect during SiO2 droplet drying, we propose for the first time to manufacture superhydrophilic and high-transmittance coatings with porous structures on various substrates, including glass and resin. This approach relies on a simple, potentially large-scale ultrasonic spray method to enhance the Marangoni flow of SiO2 dispersion with different particle sizes by adding multiple surfactants to reduce the surface tension of the dispersion. The water contact angle of the SiO2 film decreases to below 5° within 0.5 s, imparting anti-fogging properties to the substrate. The film exhibits a transmittance of 93.1 % at 580 nm, surpassing the inherent 90.8 % transmittance of the bare glass. Notably, the film shows remarkable self-cleaning properties due to potent hydration from eco-friendly SiO2 nanoparticles and the porous structure. Owing to the hydrogen bonding between tightly packed small-sized SiO2 particles as well as between the particles and substrate, the surface morphology of the film on glass remains intact even after washing, and soaking. The porous SiO2 film, with a contact angle dropping to below 5° within 0.5 s, maintains its superhydrophilicity even after being exposed to high temperatures, UV irradiation, and humidity conditions. The simple production process of the porous SiO2 films offers a promising method for preparing high-transmittance anti-fogging films with significant industrial potential.

Roughness control in the processing of 2-inch polycrystalline diamond films on 4H-SiC wafers

Diamond is an essential material for the manufacture of semiconductors devices, infrared optical windows, heat dissipation and other fields. The applications have put forward a practical demand that the diamond substrates have an ultra-smooth surface and are free of structural damage. However, precision polishing of diamond is challenging due to the extreme hardness and chemical inertness. The focus of this study is to prepare nanoscale smooth polycrystalline diamond films with roughness Ra down to 0.1 nm using chemical and mechanical synergies. After processing, the surface roughness and quality of CVD diamond film were characterized, and a material removal mechanism was proposed. The graphitization process is accelerated when diamond contacts the transition metal Fe in the mechanical polishing process. In chemical mechanical polishing process, the polished surface of diamond C is transformed into deformed diamond C* under friction. A relatively soft polishing pad is used to increase the contact area with the diamond, which is transformed into a softer, easy-to-remove structure under the action of potassium permanganate oxidant, and then the reaction layer is removed again by mechanical friction.

Analysis of the Impact of Multimedia Imaging Technology on Film Media

Multimedia imaging technology is widely used in many fields of modern life, such as traditional artistic expressions such as movies and dramas, and emerging computer multimedia technologies such as video image rendering, dynamic image processing and three-dimensional image processing are constantly emerging, providing viewers with better visual effects. At the same time, due to the limitation of shooting conditions or improper storage and reproduction, many video materials have different degrees of distortion, so it is particularly urgent to protect and repair these materials. In this context, we introduced different types of computer multimedia technology, and made a comprehensive and in-depth analysis of the media. This will help to optimize and improve the film and television production process, improve the quality of works, and protect historical video materials.

Ultralow thermal conductivity of 2D Dion-Jacobson (PDA)(FA)n - 1PbnI3n + 1 perovskite films.

Two-dimensional (2D) perovskites exhibit enhanced thermal stability compared to three-dimensional perovskites, especially the emerging 2D Dion-Jacobson (DJ) phase perovskite. However, the heat transfer mechanisms in DJ phase perovskites are rarely reported. Herein, we determine thermal conductivities of (PDA)(FA)n - 1PbnI3n + 1 films with n = 1-6 by time-domain thermoreflectance. The measured results indicate that the thermal conductivities of these films are extremely low, showing a trend from decline to rise with increasing n values, and reaching to the lowest when n = 2. We measure the propagation of acoustic phonons in films with n = 1-3 by time-domain Brillouin scattering and find phonon velocity plays a key role in the thermal conductivity, which can be explained by the mismatch of spring constants between the inorganic layer and the organic layer using the bead-spring model. The gradually increasing thermal conductivity for larger n values is attributed to the gradual transformation of the grain orientation from horizontal to vertical, which is demonstrated by the grazing-incidence wide-angle x ray scattering (GIWAXS) results. Our work deepens the understanding of the thermal transport process in 2D DJ phase perovskite films and provides insights into thermal management solutions for their devices.

Energy Yield Modeling of Perovskite–Silicon Tandem Photovoltaics: Degradation and Total Lifetime Energy Yield

This study investigates the impact of degradation in perovskite‐silicon tandem solar cells by means of energy yield (EY) modelling over the entire lifetime. First, we assess the impact on EY of degradation in the individual solar cell parameters of the perovskite top cell. Our analysis reveals that degradation in fill factor, due to a decline in perovskite top cell shunt resistance (RSh), has the most severe impact on the EY, emphasizing the imperative to rectify perovskite imperfections in thin film processing causing RSh decline. Second, we investigate implications of degradation in the perovskite top cell on the EY of current mismatched tandem solar cells. Third, we examine critical thresholds for the “acceptable degradation levels” in the perovskite top cell with regard to degradation in each solar cell parameter, assuming that the total loss in EY must be comparable to the degradation in state‐of‐the‐art silicon. Overall, our study highlights that degradation of the perovskite top cell needs to be assessed with care when extrapolating the impact on the lifetime EY of perovskite‐silicon tandem solar cells. The severity of degradation for different degradation mechanisms in a single junction perovskite solar cell cannot be translated one‐to‐one to tandem devices.

Unveiling dynamics evolution mechanism of electrochromic process in WO3-x film with thickness dependence

Response time (τ, defined as the time required for 90% change in the full transmittance modulation, including coloring time τc and bleaching time τb) is an important evaluation index for the performance of electrochromic (EC) materials, and it can directly reflect the microscopic rate of EC process. However, the research on the internal relationship between the response time and the process of electrochemical dynamics is rare. Herein, by controlling the thickness of the WO3-x EC film, a complete reversal of the response time (from τc > τb in the thinner film to τb > τc in the thicker film) is observed. Based on the detailed analysis of the characteristics presented in electrochemical impedance spectroscopy (EIS), especially focusing on the changing trend about the arc of different frequency ranges and the slope value of the linear part, it can be found that this reversal is due to the change of the main dynamics process from surface capacitive-controlled to bulk diffusion-controlled with the increase of WO3-x film thickness. Meanwhile, this change with obvious film thickness dependence requires a "trigger", which is reflected by the bleaching threshold potential. Besides, this study reveals the three stages of the EC coloring process from the perspective of dynamics, including the lithium-ions (Li-ions) adsorption charge layer, surface Faraday process, and bulk Faraday process, which also show significant film thickness dependence. The result of this work is beneficial to modulate the balance of response time and to improve the performance of EC films.

A Study of the Corrosion Resistance of 316L Stainless Steel Manufactured by Powder Bed Laser Additive Manufacturing

Commercially available 316L (1.4404) stainless steel is commonly used for industrial filtration due to its combination of good material properties, particularly its corrosion resistance, which is a critical factor for filters in corrosive (e.g., saltwater) environments. Recently, laser powder bed fusion (LPBF) has enabled new more complex and efficient filtration pieces to be manufactured from this material. However, it is critical to know how the corrosion resistance is affected by this manufacturing strategy. Here, the corrosion resistance of LPBF manufactured 316L stainless steel is compared with wrought 316L sheet. The corrosion of the samples in saltwater was assessed with asymmetric electrochemical noise, potentiodynamic polarisation curve, and electrochemical impedance spectroscopy. The samples before and after corrosion were examined with scanning electron microscopy and energy-dispersive spectroscopy. The LPBF samples had higher corrosion resistance than the sheet samples and were more noble. The corrosion resistance of the LPBF sample increased with time, while the wrought sample corrosion resistance reduced over time. The corrosion mechanism of both samples was stable with time, formed of a passive film process and a bared material process. This paper presents the first study about the temporal evolution of the LPBF 316L stainless steel corrosion mechanism.

High-temperature atomic layer deposition of silicon oxide films using Tris(dimethylamino)silane and ozone

Atomic layer deposition (ALD) benefits from high process temperatures when the substrate is not temperature-sensitive because the films deposited at higher temperatures exhibit better electrical properties. In this study, we investigated the ALD process of silicon oxide films by alternating injections of tris(dimethylamino)silane (tris-DMAS) and O3/O2 at temperatures ranging from 400 to 700 °C. The saturation dose of tris-DMAS was 1.5 × 106 L at 400 °C. Self-limiting growth with a growth rate of approximately 0.9 Å/cycle was observed up to 600 °C, allowing excellent step coverage. However, at 700 °C, the growth rate increased significantly to 4.6 Å/cycle, carbon and nitrogen impurities were detected by secondary ion mass spectrometry, and step coverage was poor, supporting the thermal decomposition of tris-DMAS at this temperature. Therefore, the optimum temperature for ALD SiO2 using tris-DMAS is 600 °C for application as an insulating film on high aspect ratio patterns. At this temperature, the leakage current density was 0.58 nA/cm2, and the oxide-trapped charge density was 4.0 × 1010 cm−2.

Semantic segmentation in crystal growth process using fake micrograph machine learning

Microscopic evaluation is one of the most effective methods in materials research. High-quality images are essential to analyze microscopic images using artificial intelligence. To overcome this challenge, we propose the machine learning of “fake micrographs” in this study. To verify the effectiveness of this method, we chose to analyze the optical microscopic images of the crystal growth process of a Ge thin film, which is a material in which it is difficult to obtain a contrast between the crystal and amorphous states. By learning the automatically generated fake micrographs that mimic the crystal growth process, the machine learning model can now identify the low-resolution real micrographs as crystalline or amorphous. Comparing the three types of machine learning models, it was found that ResUNet ++ exhibited high accuracy, exceeding 90%. The technology developed in this study for the automatic and rapid analysis of low-resolution images is widely helpful in material research.

Femtosecond laser processing of amorphous silicon films

Femtosecond laser micromachining is a pivotal approach within the dynamic field of laser surface structuring, offering unparalleled precision for materials processing. By exploiting the unique nonlinear light-matter interactions, this technique allows the creation of functional micro- and nanostructures with exceptional accuracy and reproducibility. Of particular interest is its ability to process diverse materials, including glasses, polymers, metals, and semiconductors, with minimal thermal impact and collateral damage. Moreover, femtosecond laser micromachining eliminates the need for traditional lithographic methods, enabling intricate structure fabrication under ambient conditions, thereby revolutionizing microfabrication techniques. This study demonstrates the micromachining using femtosecond lasers at 800 nm wavelength and explores the critical role of process parameters, such as laser pulse energy and the number of pulses in determining the damage threshold fluence, especially considering incubation effects in multi-pulse scenarios. Furthermore, it explores the potential of femtosecond laser micromachining for controlled crystallization in hydrogenated amorphous silicon (a-Si:H), unleashing enhanced electrical and optical properties. With its versatility, precision, and potential for diverse applications, femtosecond laser micromachining holds promise for driving advancements in electronic and photonic devices, particularly in high-efficiency photovoltaics, integrated photonics, and novel optoelectronic technologies.

A wafer-level characterization method of thin film transverse piezoelectric coefficient evaluation

Accurate measurement of the piezoelectric property of thin films is critical for thin film process development and device design optimization. In this paper, we proposed a wafer-level thin film characterization method that provides a non-destructive, single-side measurement solution for evaluating and in-process monitoring the transverse piezoelectric coefficient (e31,f). The e31,f of piezoelectric films was determined by measuring the deflection of circular electrode induced by the converse piezoelectric effect, with the electrodes fabricated on top of piezoelectric thin film on a silicon substrate. The constitutive equation of the unimorph plate reveals a quadratic dependence of top electrode deflection (δ) on the radius (r), which was subsequently utilized to calculate the e31,f while considering the electrode edge effect. Determined by non-constant variations of |δ/r2| from finite element method (FEM) simulation results, the electrode edge effect leads to the specification of electrode size and substrate thickness for evaluating piezoelectric coefficient. A comprehensive FEM simulation analysis of the influence of wafer size and electrode location on the accuracy of the proposed method demonstrated its reliability for wafer-level characterization. The e31,f measurement results of single-crystal (s-PZT) and polycrystalline PZT (p-PZT) exhibit good agreement between the proposed wafer-level method and the die-level cantilever method. These results demonstrated that the proposed single-side wafer-level method provides a reliable measurement technique for e31,f characterization of piezoelectric thin film.

Molecular dynamics study of the groove-forming mechanism of mechanically scratched grating multilayer aluminum films

For a long time, the forming quality of large area diffraction gratings is restricted by the one-time coating quality and uniformity of large thickness and large area aluminum films. Large thickness coatings, low accuracy of large depth grooves and diamond tool wear problems were the main reasons for the failure of the test to inscribe large area diffraction gratings. Therefore, the use of layered coating process can effectively ensure the uniformity and consistency of large-area and large-thickness grating blanks coated with aluminum film, and improve the high precision of large depth diffraction grating slot type. In order to reveal the mechanism of the groove-forming process of multilayer aluminum films, the microstructure and mechanical properties of different aluminum films were observed. In this article, the removal behavior and mechanism of nanomechanically scratched multilayer aluminum film materials are investigated using a molecular dynamics approach, and the characteristics of multilayer aluminum films scratched into grooves are analyzed in terms of surface morphology, scratching force, structural evolution, dislocation distribution, von Mises stress and shear strain. The results indicate that in the scratching simulation process, multilayer aluminum film has a higher number of removed atoms and a larger atomic displacement compared to single layer aluminum film, which is conducive to precise shape control of the groove. The average tangential force and normal force of multilayer aluminum film show a decreasing trend compared to single layer aluminum film, which helps to scratch grooves and reduce tool wear. The total length of the dislocation lines of the multilayer aluminum film is large, and the distribution area is large, which improves the precision of scratching the grooves. Therefore, an appropriate increase in the number of aluminum film layers has a precise control effect on the groove shape. This study has certain reference significance for analyzing the complex grooving deformation law of grating aluminum film, improving the diffraction efficiency of grating aluminum film, and further improving the manufacturing process of grating aluminum film.