3 Factors of Target Quality Influence Large-area Coating

Most modern buildings have begun to use large areas of glass for lighting, and its biggest advantage is that it can bring us brighter light and a wider view. However, since the heat energy transmitted through the glass is much higher than the surrounding walls, the energy consumption of the entire building increases significantly. In order to solve this problem, people have begun to study and apply large-area Low-E glass.

Low-E glass is commonly used in building construction because of its ability to save energy, control light, and for aesthetics. The sputtering target material is one of the essential components for making low-e glass, so this article will introduce 3 factors of target quality that influence large-area coating of low-E glass.

The shape of the target materials

For large-area coating, commonly used targets include planar targets and rotatory targets according to their shapes. The shape of the target affects the stability and film properties of the magnetron sputtering coating, as well as the utilization rate of the target. Therefore, the coating quality and production efficiency can be improved by changing the shape design of the target, and the cost can be saved.

planar targets and rotatory targets
Planar targets and rotatory targets

Relative density & porosity of the target

The relative density of the target is the ratio of the actual density to the theoretical density. The theoretical density of a single-component target is the crystal density, and the theoretical density of an alloy or compound target is calculated from the theoretical density of each component and its proportion in the alloy or mixture.

If the target material is loose and porous, it will absorb more impurities and moisture, which are the main pollution sources in the coating process. These impurities will hinder the rapid acquisition of high vacuum, easily lead to electrical discharge during the sputtering process, and even burn out the target. Find high-quality target material here: https://www.sputtertargets.net/

Target grain size and crystallographic direction

For targets of the same composition, the one with the smaller grain size has a faster deposition rate. This is mainly due to the fact that grain boundaries are more vulnerable to attack during the sputtering process, and the more grain boundaries, the faster the film formation.

In addition, the grain size also affects the quality of the film formation. For example, in the production process of Low-E glass, NiCr thin-film is used as the protective layer of the infrared reflection layer Ag, and its quality has a great influence on the coating products. Since the extinction coefficient of the NiCr film is relatively large, it is generally plated very thinly (about 3nm). If the grain size is too large and the sputtering time is short, the compactness of the film will be poor, the protective effect of the Ag layer will be reduced, and the coating product will be oxidized and removed.

Conclusion

The shape of the target mainly affects the utilization rate of the target material, and a reasonable size design can improve the utilization rate of the target material and save costs. The smaller the grain size, the faster the coating rate and the better the uniformity. The higher the purity and density, the lower the porosity, the better the quality of the film formation, and the lower the probability of slag removal by discharge.

Electron Beam Deposition for Film Coating

Introduction

Electron beam deposition is a form of physical vapor deposition (PVD) in which the target anode material is bombarded with a stream of electrons generated by a tungsten filament. Electron beam thin film deposition techniques are widely used in R&D as well as in mass production applications.

Electron beam deposition is performed in a vacuum, typically starting the process at levels below 10-5 Torr. Once a suitable vacuum is reached, a tungsten filament in the electron beam source emits a stream of electrons. This electron beam can be generated in various ways, including thermionic emission, field electron emission, or ion arc source, depending on the design of the source and associated power supply.

In all cases, the negatively charged electrons are attracted to the positively charged anode material. The generated electron beam is accelerated to high kinetic energy and directed towards the material to be deposited on the substrate. This energy is converted into heat by interacting with the atoms of the evaporated material.

The purpose of generating a stream of electrons in an electron beam source is to heat the deposited material to a temperature above a vapor pressure threshold at a given background pressure. The vapor stream is then condensed onto the surface of the substrate.

Schematic representation of electron beam evaporation system depicting various parts.
Schematic representation of electron beam evaporation system depicting various parts.. Mohanty, P. & Kabiraj, Debdulal & Mandal, R.K. & Kulriya, Pawan Kumar & Sinha, Ask & Rath, Chandana. (2014). Evidence of room temperature ferromagnetism in argon/oxygen annealed TiO2 thin films deposited by electron beam evaporation technique. Journal of Magnetism and Magnetic Materials. 355. 240–245. 10.1016/j.jmmm.2013.12.025.

Deposition Rate

As with all thermal evaporation systems, the electron beam deposition rate depends on the temperature of the material being deposited and the vapor pressure (physical constant) of that material. For elemental materials, there is a fixed vapor pressure for any particular background pressure (vacuum) and material temperature. However, for alloys or composites, there may be different partial pressures associated with each component.

Compared with Sputter Coating

Unlike sputter deposition, where individual atoms arrive at the substrate surface with very high velocity and momentum, the thermally generated vapor stream arrives at the substrate surface at a considerably lower velocity, but a much greater velocity. In other words, e-beam deposition rates can be orders of magnitude greater than sputter deposition rates, making e-beam coatings very beneficial for high volume production or thick film requirements. One disadvantage, however, is that the material tends to condense directly on the substrate surface due to the different kinetic energy of the arriving species during electron beam evaporation than that of the sputtered species. In contrast, atoms of sputtered materials tend to penetrate several atomic layers (or more) to the substrate surface before losing momentum and then establishing cohesive bonds in nucleation structures and film growth. Thus sputtered films tend to provide better adhesion properties than thermally evaporated materials.

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An Overview of Mammary Gland Molybdenum Target X-Ray Inspection

Technology Introduction

Molybdenum target inspection is a new digital imaging technology that combines traditional radiology technology with modern computer technology. It finally transforms the ordinary X-ray image into a digital image that can be quantized. The traditional X-ray film technology and the qualitative quality of image quality make it easier for radiologists to find suspicious malignant lesions in mammography, which is considered to be a method to improve the early detection rate of breast cancer.

Advantages

The mammography system has the characteristics of clear imaging, convenient and quick inspection operation, and small radiation dose. The instrument can accurately detect the shape, size, density, and nature of breast hyperplasia, lesions, masses, and calcifications. It can accurately judge and identify calcifications of breast lesions that cannot be identified by color Doppler ultrasound, and is known as the “gold standard” for international breast disease examination.

As a non-invasive method of examination, mammary gland Molybdenum target X-Ray inspection has a relatively small pain in the examination of the breast. The images retained are available for comparison before and after, regardless of the limit of age or body shape. Mammography has now become a routine breast disease examination with a sensitivity of 82% to 89% for breast cancer and a specificity of 87% to 94%.

Molybdenum target mammograms of a patient.
Molybdenum target mammograms of a patient. (a) and (b) are molybdenum target mammograms of the patient’s left breast from the craniocaudal (CC) and mediolateral oblique (MLO) views, respectively, while (c) and (d) are molybdenum target mammograms of the patient’s right breast from the CC and MLO views, respectively. Sun, Lilei & Jie, Wen & Wang, Junqian & Zhao, Yong & Zhang, Bob & Wu, Jian & xu, Yong. (2022). Two‐view attention‐guided convolutional neural network for mammographic image classification. CAAI Transactions on Intelligence Technology. n/a-n/a. 10.1049/cit2.12096. 

Unique value

1 It can be used as a relatively non-invasive method of examination, and it can fully and accurately reflect the structure of the entire breast.

2 Molybdenum target inspection can be used to observe the effects of various physiological factors (such as menstrual cycle, pregnancy, lactation, economic status and endocrine changes) on the mammary gland structure, and can be used for dynamic observation.

3 Benign lesions and malignant tumors of the breast are relatively reliably identified.

4 Breast cancer can be detected early, and even occult breast cancer that is not clinically detectable can be detected.

5 According to the Molybdenum target inspection, some precancerous lesions can be found and can be followed up for observation.

Conclusion

In conclusion, Mammary gland Molybdenum target X-Ray inspection is currently the first choice and the easiest and most reliable non-invasive detection method to diagnose breast diseases. It is relatively less painful, easy to operate, and has high resolution.

Stanford Advanced Materials (SAM) Corporation is a global supplier of various sputtering targets such as metals, alloys, oxides, and ceramic materials which are widely used in the medical industry.  We will regularly update knowledge and interesting stories of sputtering targets on our website. If you are interested, please visit https://www.sputtertargets.net/ for more information.

History of Thermal Evaporation for Thin Film Coating

Thermal evaporation, or vacuum evaporation, refers to the vaporization of evaporation materials. By heating evaporation materials to a certain temperature, the vapor pressure becomes appreciable, and the surface or molecules are lost from the surface in the vacuum. Vaporization can come from the surface of a liquid or from the surface of a solid. The equilibrium vapor pressure (EVP) is 10-2 Torr. Some evaporation materials have a vapor pressure so that they can sublime or evaporate (e.g., titanium) at temperatures near their melting points. Some composites sublime and some evaporate.

Thermal Evaporation Materials. (Gold, Silver, Titanium, Silicon Dioxide, Tungsten, Copper)
Thermal Evaporation Materials. (Gold, Silver, Titanium, Silicon Dioxide, Tungsten, Copper)

From late 1800s to early 1900s

Studies about thermal evaporation in vacuum began in the late 19th century. In the 1880s, H. Hertz and S. Stefan determined the equilibrium vapor pressure, but they did not consider using of vapor to form thin films.
In 1884, Thomas Edison applied for a patent covering the vacuum evaporation of “heating to incandescence” and film deposition. However, his patent makes no mention of the evaporation of molten materials, and many materials do not evaporate at an appreciable rate until they reach or exceed their melting point. Edison did not use the process in any application, presumably because radiant heating from the source was detrimental to the vacuum materials available at the time.

 

In 1887, Nahrwold reported the formation of platinum thin films by subliming platinum evaporation materials in a vacuum. Therefore, some believe that he was the first to use thermal evaporation to form thin films in a vacuum.

In 1907, Soddy proposed that it would be possible to evaporate solid calcium onto the surface to reduce the residual pressure in the sealed tube. This is believed to be the first “reactive deposition” process in history.

In 1909, Knudsen proposed the “Knudsen Cosine Distribution Law” for vapor from a point source. After 6 years, he refined the free surface evaporation rate as a function of equilibrium vapor pressure and ambient pressure. The resulting equation is called the Hertz-Knudsen surface equation for free-surface vaporization. Honig summarized the equilibrium vapor pressure data for 1957.

Various Types of Evaporation Pellets
Various Types of Evaporation Pellets

From the early 1900s to the mid-1900s

In 1912, von Pohl and Pringsheim reported the formation of thin films by evaporating solid materials in a vacuum using a magnesia crucible as a container. Their experiments are sometimes considered the first thin-film deposition by thermal evaporation in a vacuum.

In 1931, Ritschl reported thermal evaporation of silver from a tungsten wire basket to form half-silvered mirrors. And he is often credited with being the first to use evaporation from a filament to form a film in a vacuum.

Evaporating Aluminum Thin-Film

Cartwright and Strong reported on the evaporation of metals from tungsten wire baskets in the same year. However, their attempts to vaporize aluminum failed, because molten aluminum would wet with the tungsten filament to form an alloy, which causes it to “burn out” when there is a relatively large volume of molten aluminum.

Aluminum thin films were not successfully produced by vacuum evaporation until 1933, when John Strong used large gauge tungsten filaments wetted by molten aluminum. John has done extensive development work for astronomical mirror coatings using the aluminothermic evaporation of multiple tungsten wires. Strong, with the help of designer Bruce Rule, used multiple filaments and a 19-foot diameter vacuum chamber to aluminize the 200-inch Palomar telescope mirror in 1947.

AR Coating

In 1933 A.H. Pfund vacuum-deposited the first single-layer (AR) coating (ZnS) while reporting on making beamsplitters and Bauer mentioned AR coatings in his work on the properties of alkali halides.

The Germans deposited CaF2 a nd MgF2 AR coatings during WWII. Plasma cleaning of glass surfaces is reported to have been used by Bauer at the Zeiss Company in 1934. The Schott Company (Germany) was also reported to have deposited three-layer AR coatings by flame-pyrolysis CVD during WWII.

In 1935, based on Bauer’s observation, A. Smakula of the Zeiss Company developed and patented AR coatings on camera lenses. The patent was immediately classified as a military secret and was not revealed until 1940.

In1936, Strong reported depositing AR coatings on glass.

In 1939, Cartwright and Turner deposited the first two-layer AR coatings.

One of the first major uses of coated lenses was on the projection lenses for the movie Gone With the Wind, which opened in December 1939. The AR-coated lenses gained importance in WWII for their light-gathering ability in such instruments as rangefinders and the Norden Bombsight.

The AR coated lenses gained importance in WWII for their light-gathering ability in such instruments as rangefinders and the Norden Bombsight. During WWII, baking of MgF2 films to increase their durability was developed by D.A. Lyon of the U.S. Naval Gun Factory. The baking step required that the lens makers coat the lens elements prior to assembly into compound lenses.

In 1943, the U.S. Army sponsored a conference on “Application of Metallic Fluoride Reflection Reducing Films to Optical Elements.” The proceedings of this conference are probably the first extensive publication on coating optical elements.

In 1958, the U.S. military formally approved the use of “vacuum cadmium plating” (VacCad) for application as corrosion protecmium. In recent years Physical Vapor Deposition (PVD) methods have been used to replace electroplating in a number of applications to avoid the water pollution associated with electroplating.

From the mid-1900s to the late 1900s

E-beam Evaporation Development

In 1949, Pierce described the “long-focus” electron beam gun for melting and evaporation in a vacuum. The long focus gun suffers from shorting due to the deposition of evaporated material on the filament insulators that are in the line of sight of the evaporating material. Deposition rates as high as 50 µm/s have been reported using e-beam evaporation. To avoid exposure of the filament to the vapor flux, bent-beam electron evaporators were developed.

In 1951, L. Holland patented the use of accelerated electrons to melt and evaporate the tip of a wire (“pendant drop”), which involved no filament or crucible.

In 1968, Hanks filed a patent on a 270° bent beam electron beam evaporation source that has become the most widely used design. Mastering the electron beam allows the energy of the electron beam to be distributed over the surface.

In 1970, Kurz was using an electron-beam system to evaporate gold for web coating. In electron beam evaporation a high negative “self-bias” can be generated on the surface of an insulating material or on an electrically isolated fixture. This bias can result in high-energy ion bombardment of the self-biased surface.

In 1971, Chambers and Carmichael avoided that problem by having the beam pass through a small hole in a thin sheet in a section of a plate that separated the deposition chamber from the chamber where the filament was located. This allowed a plasma to be formed in the deposition chamber while the filament chamber was kept under a good vacuum. The plasma in the deposition chamber allowed ion bombardment of the depositing film material as well as “activation” of reactive gas.

In 1972, the use of a hollow cathode electron emitter for e-beam evaporation was reported by J.R. Morley and H. Smith.

In 1978 H.R. Smith described a unique horizontally emitting electron beam (EB) vapor source. The source used a rotating crucible to retain the molten material, and its function was to coat large vertical glass plates. A number of thermoelectron-emitter e-beam source designs followed, including rod-fed sources and “multi-pocket” sources. The high voltage on the filament prevented the source from being used in a plasma where ions accelerated to the cathodic filament; this caused rapid sputter-erosion of the filament.

Crucible material Development

In 1951 Picard and Joy described the use of evaporation of materials from an RF-heated crucible. In 1966 Ames, Kaplan, and Roland reported the development of an electrically conductive TiB/BN composite ceramic (Union Carbide Co., UCAR™) crucible material that was compatible with molten aluminum.

Directed Deposition Development

The directed deposition is confining the vapor flux to one axis by eliminating off-axis components of the flux. Directed deposition can be attained by the collimation of the vaporized material. This was done in evaporation by Hibi (1952), who positioned a tube between the source and the substrate. Collimation was also attained by H. Fuchs and H. Gleiter in their studies of the effects of atom velocity on film formation using a rotating, spiral-groove, velocity selector.

In 1983, Ney described a source that emitted a gold atom beam with a 2° divergence. Recently, “directed deposition” has been obtained using a flux of thermal evaporated material projected into a directed gas flow.

Thermally Evaporating Development

When thermally evaporating alloys, the material is vaporized with a composition in accordance with Raoult’s Law (1887). This means that the deposited film will have a continuously varying composition unless very strict conditions are met as to the volume of the molten pool using a replenishing source. One way of avoiding the problem is by “flash evaporation” of small volumes of material.

In 1948, L. Harris and B.M. Siegel reported flash evaporation by dropping small amounts of material on a very hot surface so that all of the material was vaporized before the next material arrived on the hot surface.

In 1964, Smith and Hunt described a method for depositing continuous strips of alloy foils by evaporation. Other free-standing thin-film structures are also deposited, such as beryllium Xray windows and nuclear targets.

To learn more about the history of thermal evaporation, please follow our website. We will update articles about evaporation pellets every week, so stay tuned. If you want to buy high-quality evaporating pellets, please visit our official website for coating materials at https://www.sputtertargets.net/.

Evaporation Coating Experiment: Principle, Purpose & Results

Introduction

In recent years, the rapid economic development and the continuous improvement of people’s living standards have led to the continuous emergence of high-tech thin-film products, especially in the field of electronic materials and components. Vacuum coating technology has also gained significant application in this field.

At present, the common film-forming methods include vapor-phase film-forming method, oxidation method, ion implantation method, diffusion method, electroplating method, coating method, liquid-phase growth method, etc. The vapor generation method can be further subdivided into physical vapor deposition, chemical vapor deposition, and discharge polymerization.

Principle

The experiments listed in this article are related to physical vapor deposition coatings. This method is basically carried out under vacuum, so it is called vacuum coating technology.

Vacuum evaporation, sputter coating, and ion plating are commonly referred to as basic physical vapor deposition thin film preparation techniques. The vacuum evaporation coating method is a method in which the evaporation material of a film to be formed in a vaporization chamber is heated in a vacuum chamber, and atoms or molecules are vaporized from the surface to form a vapor stream, which is incident on the surface of the substrate and condensed to form a solid film.

Evaporation Coating

Purposes

  1. To familiarize yourself with the operating procedures and methods obtained by vacuum;
  2. In order to understand the principle and method of evaporation coating;
  3. To learn how to use evaporation coating technology.

Results

(1) Vacuum conditions during evaporation

When the average free path of the vapor molecules in the vacuum vessel is greater than the distance between the evaporation source and the substrate (called the steaming distance), sufficient vacuum conditions are obtained. For this reason, it is necessary to increase the mean free path of the residual gas to reduce the collision probability of the vapor molecules with the residual gas molecules, and to evacuate the vacuum chamber to a high vacuum.

(2) How to choose evaporation source selection

1 It should have good thermal stability, chemical inactivity; the vapor pressure of the heater itself is sufficient to reach the evaporation temperature.

2 Its melting point should be higher than the evaporation temperature of the evaporated material. The heater should have a large enough heat capacity.

3 The mutual melting of the evaporated material and the evaporation source material must be very low, and it is difficult to form an alloy.

4 The material used for the coil-shaped evaporation source is required to have a good wetting with the evaporation material and a large surface tension.

5 For a case where it is difficult to form a filament, or when the surface tension of the evaporation material and the filament evaporation source is small, a boat-shaped evaporation source can be used.

(3) Main physical processes of thermal evaporation coating

1 Using various forms of thermal energy conversion to vaporize or sublimate the coating material into gaseous particles (atoms, molecules or atomic groups) with certain energy (0.1~0.3eV);

2 Gaseous particles are transported to the substrate by a substantially collision-free linear motion;

3 Particles are deposited on the surface of the substrate and agglomerated into a film.

(4) Factors affecting the quality and thickness of vacuum coating

There are many factors affecting the quality and thickness of the vacuum coating, including the degree of vacuum, the shape of the evaporation source, the position of the substrate, and the temperature of the evaporation source. The solid matter has very low evaporation at normal temperature and normal pressure. The higher the degree of vacuum, the easier it is for the molecules of the evaporation source material to scatter away from the surface of the material. The fewer molecules in the vacuum chamber, the lower the probability that the evaporating molecules will collide with the gas molecules, so that the surface of the substrate can be reached unobstructed straight.

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Sources and Hazards of Industrial Waste Salt

Overview

Industrial waste salt mainly comes from industrial waste salt-containing organic matter and other toxic salt-containing waste liquids and solids produced in the production process of chemical, pharmaceutical, agrochemical and coal chemical industries. The main salt production links include reaction salts from mother liquor (process wastewater), neutralizing salts from acid-base chemical reactions, salting-out salts, and salt sludge from distillation residues.

The organic matter in waste salt has a complex composition, which has the characteristics of various types, complex components, numerous sources, high treatment costs, and great environmental hazards.

At present, waste salt is generally treated by building a warehouse and centralized temporary storage. Faced with high storage and management costs, it is difficult for enterprises to afford it, and it has become a “stuck neck” problem that restricts the development of enterprises.

At the same time, industrial waste salt is also an important chemical raw material. If the waste salt from chemical by-products can be recycled as industrial raw material salt, it can not only eliminate its pollution to the environment, but also make full use of salt resources to realize the resource and recycling of by-product salt.

In this context, the harmless and comprehensive utilization of waste salt has become an inevitable way to dispose of waste salt, and the main factor restricting its large-scale development is the removal of organic matter in waste salt.

Industrial Waste Salt

Sources and Characteristics of Industrial Waste Salt

There are many industries involved in the generation of waste salt. The types of waste salt produced include single waste salt, mixed salt and mixed salt (including impurities). According to the particularity of its production process and the difference in production links, the waste salt produced by different industries is quite different.

PESTICIDE PRODUCTION

Among them, pesticide production is the main industry for waste salt generation. Its main source is the production process of pesticide intermediates and original drugs. Pesticide waste salts contain a lot of organic matter, mainly halogenated hydrocarbons and benzene-based complex components, and the boiling point and thermal decomposition temperature of the organic compounds are within 200-600 °C.

PRINTING AND DYEING

The basic production raw materials in the printing and dyeing industry include naphthalene, anthraquinone, benzene, aniline and benzidine compounds. These substances are easy to chelate with metals, salts and other substances during the processing and production process, so the dye wastewater contains high concentrations of salts and heavy metals.

In the process of water treatment, the evaporation of high-salt wastewater will also indirectly generate waste salt. Such waste salts go through the oxidation and decomposition process of organic matter in the pre-water treatment process, so the residual organic matter is mostly refractory organic matter, which is difficult to remove.

COAL CHEMICAL INDUSTRY

The waste salt in the coal chemical industry mainly comes from the salt introduced in the production of demineralized water and circulating water, and the components are mainly simple salts such as NaCl and Na2SO4, without organic matter. In the chlor-alkali industry, NaOH, Cl2 and H2 are prepared by electrolysis of saturated NaCl solution, and a series of chemical products are produced by using them as raw materials. This kind of salt mud has a large output, the main component is NaCl, basically does not contain organic matter, and has high recycling value.

In addition, the petrochemical, coal chemical, Chlor-alkali industry, metallurgy and other industries also produce waste salt, but the organic content is relatively low, and the processing difficulty is relatively small.

Treatment Methods

WET PROCESS

Wet treatment first dissolves waste salt in water, and degrades organic pollutants through deep oxidation technology in the field of water treatment to achieve harmlessness of waste salt. Commonly used organic oxidation technologies include advanced oxidation, wet catalytic oxidation and hydrothermal oxidation.

DRY METHOD

Dry disposal of industrial waste salt mainly includes incineration, high-temperature thermal melting, and organic carbonization pyrolysis. Because of its long-term environmental hazards, occupation of land resources and legal risks, the safe landfill method can no longer meet the needs of waste salt disposal.

We will also write related articles to introduce these two methods in detail, please pay attention to our later updated articles. For more information, please visit https://www.sputtertargets.net/.

Study on Preparation Methods of Magnesium Film Materials

Thin-film is a rapidly developing material in the field of modern material science and technology, and there are many methods for its preparation. This article introduces several methods for preparing thin films, focusing on magnetron sputtering and ion beam sputtering deposition, and using magnesium sputtering targets as raw materials to prepare magnesium thin films.

Magnesium is in a diagonal position with lithium in the periodic table of the elements, has similar chemical properties to lithium, and has some electrochemical properties better than lithium, which can meet the needs of power batteries. Magnesium batteries have many advantages such as low cost, non-toxicity, no pollution, stable discharge voltage, high specific energy, high specific power, rich resources, and renewable. However, magnesium batteries have not been widely used. One of the main reasons is that magnesium is severely polarized and corroded in the electrolyte, making it unable to meet the applicable standards and difficult to meet the actual requirements. Research on magnesium thin-film materials can help improve this defect of magnesium batteries.

Principle of magnetron sputtering coating

Sputter deposition is the process whereby particles of sputtering materials are sputtered out and deposited on a substrate to form a film. Since ions are charged particles, we can add magnetic fields to control their speed and behavior. And that’s how its name “magnetron sputtering” comes from.

Under the action of an electric field of several hundred to several thousand electron volts, the plasma is accelerated and obtained sufficient force to bombard the cathode, causing the atoms of the solid sputtering target to be ejected in a typical line-of-sight cosine distribution. These atoms will condense on the surface of the substrate to form a thin film.

Ion beam sputtering coating

Ion beam sputtering (IBS), or ion beam deposition (IBD), is a thin film deposition technology that uses an ion source to deposit a sputtering target onto a substrate to produce the highest quality films with excellent precision. Compared to other PVD technologies, ion beam sputtering is more accurate and can accurately control the thickness of the substrate. As shown below, an IBS system usually includes the ion source, the target material, and the substrate. The ion beam, usually generated by the ion gun, is focused on the sputtering target, and the sputtered target material finally deposits onto the substrate to create a film.

Preparation of magnesium film material

In the preparation of magnesium-thin films, magnetron sputtering is a very good choice. This method has the advantages of high speed, low temperature and low damage. The deposited layer is uniform, dense, has small pinholes, high purity, and has strong adhesion. These advantages are the key to the quality of magnesium films. The selected targets are high-purity powder-pressed magnesium sputtering targets and magnesium alloy sputter targets.

For more information about thin-film coating, please visit https://www.sputtertargets.net/.

What are the advantages of carbon fiber composite materials used in aeroplanes?

Carbon fiber is a kind of special fiber mainly composed of carbon element and generally contains more than 90% carbon. Carbon fiber has the characteristics of high-temperature resistance, friction resistance, electrical conductivity, thermal conductivity, and corrosion resistance to general carbon materials. However, unlike ordinary carbon materials, its shape has significant anisotropy, and it shows strong strength along the fiber axis.

With its own unique advantages, carbon fiber reinforced composites have also been widely used in the aircraft manufacturing industry. Especially for smaller airplanes, carbon fiber composites are the best choice.

As a kind of carbon fiber, carbon fiber composite material has a wide range of applications in many fields due to its characteristics of high strength, lightweight, stable chemical properties, high-temperature resistance, and strong durability. Applying it to the fuselage and wings of an airplane can reduce the weight of the airplane by about 40%, and its crawling ability can be increased by 1.8 times compared with the airplane of ordinary materials.

Compared with military and civil aircraft, model aircraft are smaller in size, shorter in-flight operation time, and the working environment is relatively better. Applying carbon fiber composite materials to model aircraft can increase their service life, so they can be applied to the harsh environments.

aircraft concord

The application of carbon fiber composite materials to airplane aircraft can not only reduce the mass of the airplane but also increase the strength tolerance range of the airplane aircraft to a certain extent. The fuselage and propeller made of carbon fiber composite materials reduce the weight of the airplane while increasing its strength, thereby reducing its volume.

With the continuous development of the aerospace industry, the demand for carbon fiber composites is increasing. At the same time, people have put forward higher requirements for the quality of carbon fiber composite materials, which in a certain sense promotes the development of carbon fiber composite materials in the direction of multifunctionality, low cost and high performance.

Compared with glass fiber, the application cost of carbon fiber is also relatively high, and it is more difficult to promote and use it in a wide range. From the current situation, the price of carbon fiber materials has not only declined, but also shown an upward trend. To solve this problem, new processes must be studied to reduce the cost of carbon fiber composites.

Carbon fiber materials can also be made into the carbon sputtering target for aviation coatings. Stanford Advanced Materials provides high-quality sputtering targets and evaporation materials. Please visit https://www.sputtertargets.net for more information.

Preparation of Molybdenum Sputtering Targets by Powder Metallurgy

Molybdenum film has many advantages such as good electrical conductivity and thermal stability, chemical resistance, and low thermal expansion coefficient. It has been widely used in solar power generation, computer circuits, flat panel displays, storage media, and other aspects.

The magnetron sputtering technology has many advantages such as densely rented thin films, low surface roughness, good film-base bonding force, high deposition rate, low substrate temperature, and convenient deposition of thin films with high melting points. It is currently the main method for preparing molybdenum films using molybdenum sputtering targets.

Previous studies have shown that the choice of different magnetron sputtering equipment and process parameters (target current, target power, gas pressure, sputtering time, etc.) should also have a close relationship with the differences in the structure and performance of the sputtered thin films.

molybdenum target powder metallurgy

The electronic display industry’s technical requirements for sputtering targets mainly include indicators such as chemical purity, density, grain size and size distribution, grain orientation and orientation distribution. Recent studies have shown that the smaller the grain size of the target, the higher the sputtering rate; the more uniform the grain size distribution of the target, the easier it is to obtain a sputtered film with uniform thickness.

Since molybdenum is a high melting point (2620 ° C) metal. Powder metallurgy is the main method for preparing molybdenum targets. The process mainly includes the steps of milling, pressing, and sintering.

The powder metallurgy method is a technical method in which metal powders, alloy powders or mixed powders of metals and non-metals are directly made into various products through pressing, sintering and other processes. The main feature of this method is that it can produce special material products that are difficult to achieve or cannot be manufactured by conventional metallurgical methods or material processing methods, such as parts of machines made of refractory tungsten and molybdenum metals.

The main features of powder metallurgy are: the raw materials can be directly manufactured into qualified products according to the shape and size requirements of parts and components without mechanical cutting or slight cutting; suitable for mass production and high efficiency; Less waste during production and high utilization of raw materials. This method has been widely used in the automotive industry, energy industry, chemical industry, national defense industry, and aviation and aerospace industries.

For more information, please visit https://www.sputtertargets.net/.

Advantages of Sputtering Deposition and Vacuum Evaporation

For all devices, there is a need to go from semiconductor to metal. Thus we need a means to deposit metals, also called film coating. There are currently several methods for depositing metal thin film layers, and many of these techniques for metal deposition can also be used to deposit other materials.

1.) Physical Vapor Deposition (PVD)

2.) Electrochemical techniques

3.) Chemical Vapor Deposition (CVD)

This passage will talk about the advantages of two PVD methods: Sputtering and evaporation.

Sputtering Deposition

magnetron-sputtering-system
Magnetron Sputtering System

The plasma under high pressure is used to “sputter” metal atoms out of the “target”. These high-energy atoms are deposited on a wafer near the sputtering target material. Higher pressures result in better step coverage due to more random angular delivery. The excess energy of the ions also helps increase surface mobility (the movement of atoms on the surface).

Advantages: Better step coverage, less radiation damage than E-beam evaporation, easier to deposit alloys.

Disadvantages: Some plasma damage including implanted argon. Good for ohmics, not Schottky diodes.

Vacuum Evaporation

Evaporation (PVD)
Evaporation (PVD)

Evaporation is based on the concept that there exists a finite “vapor pressure” above any material. The material either sublimes (direct solid to vapor transition) or evaporates (liquid to vapor transition).

Advantages: Highest purity (Good for Schottky contacts) due to low pressures.

Disadvantages: Poor step coverage, forming alloys can be difficult, lower throughput due to low vacuum.

PVD Film Morphology

The three zone model of film deposition as proposed by Movchan and Demchishin
The three zone model of film deposition as proposed by Movchan and Demchishin

1.) Porous and/or Amorphous —> Results from poor surface mobility =low temperature, low ion energy (low RF power/DC bias or higher pressures=less acceleration between collisions).

2.) “T-zone”: Small grain polycrystalline, dense, smooth and high reflectance (the sweet spot for most metal processes) Results from higher surface mobility =higher temperature or ion energy

3.) Further increases in surface mobility result in columnar grains that have rough surfaces. These rough surfaces lead to poor coverage in later steps.

4.) Still further increases in surface mobility result in large (non-columnar) grains. These grains can be good for diffusion barriers (less grain boundary diffusion due to fewer grains) but pose problems for lithography due to light scatter off of large grains, and tend to be more rigid leading to more failures in electrical lines.

For more information, please visit https://www.sputtertargets.net/.