Introduction to Aluminum, Aluminum Alloy and Aluminum Sputtering Target

Aluminum is a light metal with low density (2.79/cm3), good strength and excellent plasticity. As for aluminum alloy, the strength of super-hard aluminum alloy can reach 600Mpa, and the tensile strength of ordinary hard aluminum alloy can reach 200-450Mpa, which is much higher than steel in steel. Therefore, aluminum and aluminum alloy are widely used in machinery manufacturing.

The conductivity of aluminum is second only to silver and copper, so aluminum is used in the manufacture of various conductors. Aluminum also has a good thermal conductivity that can be used as a variety of heat dissipating materials. Besides, aluminum has good corrosion resistance and excellent plasticity, and is suitable for various pressure processing.

Aluminum alloy

Aluminum alloy can be divided into the deformed aluminum alloy and the cast aluminum alloy according to the processing method.

The deformed aluminum alloy can be further divided into a non-heat treatable reinforced aluminum alloy and a heat treatable reinforced aluminum alloy. Non-heat-treated reinforced aluminum alloy cannot improve the mechanical properties by heat treatment, and can only be strengthened by cold working deformation. It mainly includes high-purity aluminum, industrial high-purity aluminum, industrial pure aluminum and rust-proof aluminum. The heat-treatable reinforced aluminum alloy can be improved in mechanical properties by heat treatment such as quenching and aging, and can be classified into hard aluminum, wrought aluminum, super-hard aluminum, and special aluminum alloy. The aluminum alloy can be heat treated to obtain good mechanical properties, physical properties and corrosion resistance.

Cast aluminum alloy can be divided into aluminum silicon alloy , aluminum-copper alloy, aluminum-magnesium alloy and aluminum-zinc alloy according to chemical composition. Cast aluminum alloy is classified into four types according to the main elements other than aluminum in the composition: silicon, copper, magnesium and zinc.

Aluminum

Pure aluminum products

Pure aluminum products are divided into two categories: smelting and pressure processing. The former is represented by chemical composition Al, and the latter is represented by LG (aluminum, industrial). The aluminum sputtering target is a kind of pure aluminum product.

Pressure processing aluminum alloy

Aluminum alloy pressure processing products are divided into seven categories: rustproof (LF), hard (LY), forged (LD), superhard (LC), coated (LB), special (LT) and brazed (LQ). The state of the commonly used aluminum alloy material is three types of annealing (M igniter), hardening (Y), and hot rolling (R).

Aluminum sputtering target

The aluminum sputtering target is one of the sputtering targets used in the vacuum coating industry, and is therefore called aluminum sputtering target. The aluminum target is obtained after a series of processing of high-purity aluminum. It is available in a specific size and shape, which is mounted on a vacuum coater to form a film on the surface of the substrate by sputtering.

Please visit https://www.sputtertargets.net/ for more information.

Boron Nitride Crucible Use Guide

Boron nitride crucible is used at a temperature of approximately 1800 degrees under vacuum and at a temperature of approximately 2100 degrees under atmospheric protection, making it ideal for ultra-high temperature forging.

BN crucible is best used in the nitrogen or argon atmosphere and has the longest life in that environment. The thermal resistance of boron nitride crucible is good. Even if the temperature suddenly becomes cold when it is used at 1500 degrees, it will not crack; after holding it for 20 minutes in a 1000 degree furnace, take it out and blown and quenched it continuously for hundreds of time, it won’t crack, either.

bn crucible

Precautions for use

1 When boron nitride is used in air, the temperature should not exceed 1000 degrees; if the temperature exceeds 1000 degrees, the contact surface of boron nitride and oxygen will oxidize and peel off.

2 Boron nitride is easy to absorb moisture, so BN crucible can not be stored in wet areas, can not be washed, but can be directly wiped with sandpaper or scrubbed with alcohol.

3 Applications of boron nitride

[Available materials]

  1. Ferrous metal: iron, copper, aluminum, nickel, magnesium, bismuth, zinc, etc., alloy FE-CO-NI-SI CO-ZR-NB
  2. Does not react with water or acid at normal temperature. Slowly hydrolyze with water to form boric acid and ammonia
  3. Rare earth, nitride

bn crucible-2

[Unavailable materials]

  1. Antimony trioxide, chromium oxide pentoxide, molybdenum trioxide, arsenic trioxide, titanium carbide, etc.
  2. The high-lead glass glaze melts in the air at 800-950 °C, but it does not react under the protection of nitrogen or inert gas. 3. Boron phosphate erodes boron nitride in 1400 ° nitrogen, and reacts with hot concentrated or molten alkali and hot chlorine.

For more information about evaporation e-beam source used crucibles, please visit https://www.sputtertargets.net/e-beam-source-used-crucibles.html.

Application of Indium Tin Oxide in Anti-Reflection Film Design

The indium tin oxide (ITO) transparent conductive film belongs to an N-type oxygen-deficient semiconductor material. It has low absorption of visible light and has high visible light transmittance, excellent infrared reflection performance and microwave attenuation performance in the mid-far infrared range. ITO transparent conductive film has become an important optical component in the field of optoelectronic devices due to its excellent photoelectric performance.

indium tin oxide evaporation pellets

ITO materials have long been used as transparent conductive films in the form of single-layer films, but their average transmittance in the visible portion is very low, generally less than 90%, and the reflectance is high, affecting its display and electromagnetic shielding applications. If the transmittance in the visible light region is improved, the application of the ITO transparent conductive film will be more extensive.

The ITO film is usually made of the indium tin oxide sputtering target and the indium tin oxide evaporation material. The use of the ITO film as one of the antireflection film systems can greatly increase the transmittance of the transparent conductive film in the visible light portion, and solves the problem that the transparent conductive film is generally low in visible light transmittance. A multilayer anti-reflection film containing TTO material was prepared by a low-pressure reactive ion plating method, and a transparent conductive film having an average visible light transmittance of 95.83%, a maximum transmittance of 97.26%, and a sheet resistance of 13.2 to 24.6 Ω was obtained. The anti-reflection film largely alleviates the contradiction between the conductivity and the transparency of the transparent conductive film, and the ITO transparent conductive film has more useful practical value and application prospect in the field of application.

indium tin oxide uses

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Rotatable Sputtering Targets Merits and Weakness

Sputtering is a high-speed process where superfast ions hit a sputtering target and dislodge minuscule particles that in turn coat a thin film on substrates like architectural glass, LED televisions and computer displays.

Rotatable sputtering target, or rotatory target, is a commonly used target shape in magnetron sputtering. It is generally cylindrical, with a stationary magnet inside, and a slow magnetic field, which allows the sputtering rate to be uniform and the target utilization rate to be high. Rotating targets are commonly used for coating solar cells, architectural glass, automotive glass, semiconductors, and flat-panel TVs.

The main advantage of the rotatable target is the high utilization of the target, which means that the rotating target can solve the problem of low utilization of the planar target.

Rotatory Copper (Cu) Sputtering Target
Rotatory Copper (Cu) Sputtering Target

For a planar sputtering target, the target utilization of the normal cathode can reach 25%, and the special design of the magnet bypass with the target back can increase the target utilization to about 40%. Despite this, the utilization of planar targets is still not high. However, the utilization of cylindrical rotating targets is typically in the range of 75% to 90%, much higher than planar targets. However, when the rotating target is used for large-area coating, the uniformity of the surface of the film layer is poor and it is difficult to meet the requirements, which is the biggest disadvantage of the rotating target.

Materials Planar Rotatory
Metal Planar molybdenum target, planar copper target, planar titanium target, planar tungsten target, planar zirconia target

 

Rotatory molybdenum target, rotatory copper target, rotatory titanium target, rotatory tungsten target, rotatory zirconia target

 

Oxides Planar SiO2 Sputtering Target Rotatory ATO Sputtering Target, rotary Nb2Ox sputtering target, rotatory TiOx sputtering target, rotatory Al2O3 sputtering target
Alloy Planar Cr-Ta sputtering target, planar Ti-Al-Si sputtering target SnO2-Sb2O3 rotatory sputtering target

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

Sputtering Target Materials for Vacuum Thin Film Coating

The sputtering target is a key required material for vacuum film coating. It refers to a material that can ionize the surface by the current-binding magnetic field.

Almost all sputter coating equipment uses a powerful magnet to spiral the electrons to accelerate the ionization of the argon around the target, resulting in an increased likelihood of collision between the target and the argon ions, thereby increasing the sputtering rate.

Typically, most metal plating uses DC sputtering, while non-conductive ceramic materials use RF sputtering. The basic principle is that argon (Ar) ions are struck against the target surface by glow discharge in a vacuum, and cations in the plasma are accelerated as a sputter material to the surface of the negative electrode. The impact will cause the material of the target to fly out and deposit on the substrate to form a film.

Generally, the sputter coating process has several features:

(1)Many materials can be deposited into thin film materials by sputtering, including metals, alloys, insulators, and the like.

(2)Under appropriate conditions, different component target materials can be made into films of the same material.

(3)Oxides or other compounds of the target substance and gas molecules can be prepared by adding oxygen or other reactive gas to the discharge atmosphere.

(4)Highly accurate film can be obtained by controlling the magnitude of the input current and the length of the sputtering time.

(5)For large-area coatings, sputter deposition is definitely superior to other coating processes.

(6)In the vacuum vessel, the sputtered particles are not affected by gravity, and the positions of the target and the substrate can be freely aligned.

(7)The bond strength between the sputter-coated substrate and the film is 10 times or more the adhesive strength of a general evaporated deposited film. Furthermore, since the sputtered particles have high energy, the surface of the film is continuously diffused to obtain a hard and dense film. At the same time, high energy allows the substrate to obtain a crystalline film at a lower temperature.

(8)The nucleation density at the initial stage of film formation is high, and an extremely thin continuous film of 10 nm or less can be produced.

(9)Sputtering targets have a long service life and can be continuously produced over a long period of time.

(10)The sputtering target can be made into various shapes. By special design of the shape of the target, the sputtering process can be better controlled and the sputtering efficiency can be most effectively improved.

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

Pros and Cons of Ion Beam Sputtering

Advantage

1 Ion beam sputtering relies on momentum exchange to make atoms and molecules of solid materials enter the gas phase. The average energy generated by sputtering is 10 eV, which is about 100 times higher than that of vacuum evaporation. After deposited on the surface of the substrate, these particles still have enough kinetic energy to migrate on the surface of the substrate, so that the film has good quality and is firmly bonded to the substrate.

2 Any material can be coated by ion beam sputtering, and even a high-melting material can be sputtered. For alloys and compound materials, it is easy to form a film having the same ratio as the composition of the sputtering target, and thus sputter coating is widely used.

3 The incident ions of the ion beam sputter coating are generally obtained by a gas discharge method, and the working pressure is between 10-2 Pa and 10 Pa. Sputtered ions often collide with gas molecules in the vacuum chamber before flying to the substrate, so the direction of motion randomly deviates from the original direction. Sputtering is generally ejected from a larger sputter target surface area and is, therefore, more uniform than that obtained by vacuum coating. For coating parts with grooves, steps, etc., the sputter coating can reduce the difference in film thickness caused by the cathode effect to a negligible extent. However, sputtering at higher pressures will result in more gas molecules in the film.

ion beam sputtering deposition

4 Sputtering can precisely focus and scan the ion beam, change the target material and substrate material while maintaining the characteristics of the ion beam, and independently control the ion beam energy and current. Since the energy of the ion beam, the beam size and the beam direction can be precisely controlled, and the sputtered atoms can directly deposit the film without collision, the ion beam sputtering method is suitable as a research method for thin film deposition.

Disadvantage

The main disadvantage of ion beam sputtering is that the target area of the bombardment is too small and the deposition rate is generally low. What’s worse, ion beam sputter deposition is also not suitable for depositing a large-area film of uniform thickness. And the sputtering device is too complicated, and the equipment operating cost is high.

For high purity sputtering target inquiry, please visit Stanford Advanced Materials.

Introduction to the Process and Steps of Evaporation Coating

The basic process flow for evaporation coating is:

Preparation before coating→ vacuum→ ion bombardment→ baking→ premelting→ evaporation→ removing parts→ film surface treatment→ finished product

1. Preparation before coating

The process includes vacuum chamber coating part cleaning, evaporation source making and cleaning, installation of evaporation source and evaporation materials.

The amount of bonding between the film layer and the surface of substrate is an important indicator of product quality. It is determined by many factors, and the surface treatment before coating is one of the most basic factors. If there is grease on the surface of the coating part, adsorbing water, dust, etc., it will reduce the bonding force of the film layer and affect the surface roughness. Cleaning is generally done by several methods: chemical degreasing, electrostatic dedusting and primer application.

According to the requirements of the product and the material of the coating parts, selecting the appropriate evaporation material is the basic condition for obtaining a high-quality film layer. For different evaporation materials, the corresponding evaporation source and the evaporation method should be selected.

The basic principle of selecting metal evaporation materials is: good thermal stability and chemical stability, high mechanical strength, low internal stress, and certain toughness, good bonding with primer, high reflectivity, and small gas release in vacuum; the material source is wide, the price is low, and it has a corresponding evaporation source.

2. Vacuum step

Open the cooling water valve, adjust to the required water pressure, turn on the main power supply, close the atmospheric valve leading to the vacuum chamber, close the pipeline valve, start the mechanical pump power supply, and open the pre-vacuum valve; At this time, the vacuum chamber is evacuated using a diffusion pump or a mechanical pump, and baking, pre-melting, and evaporation are performed when the degree of vacuum reaches a certain value.

3. Ion bombardment

In the glow discharge, the ion bombardment electrons obtain a high speed, and the negative charge is rapidly generated around the substrate due to the large mobility of the electron. Under the action of the negative charge attraction, the positive ion bombards the surface of the coating part, and the substrate. There is energy exchange on the surface, and a chemical reaction occurs between the adsorption layer of the coating member and the active gas to achieve the effect of cleaning the surface.
The conditions of ion bombardment are that the residual gas pressure is stable at 0.13~13Pa, the voltage is 1.5~10kV, and the time is 5~60min.

4. Baking

It can accelerate the rapid escape of the gas adsorbed by the coating parts or the clamp, which is beneficial to improve the vacuum degree and the film bonding force. When baking, it should be noted that the non-metal baking temperature is lower than the hot deformation temperature of the coating part by 20~30 °C, and the metal baking is generally not more than 200 °C.

5. Pre-melting

This step can remove the low melting point impurities in the evaporation material and the gas adsorbed in the evaporation source and the evaporation material, which is favorable for the smooth progress of evaporation. The pre-melted vacuum is generally 6.6 x 10-3 Pa. For materials with high hygroscopicity, it should be pre-melted repeatedly. The overall requirement is that the vacuum does not drop as the evaporating material warms to the evaporating temperature.

6. Evaporation

Evaporation technology has a great impact on film quality. There are different requirements for general metals, special metals and compound evaporating pellets. For example, some metal particles need to be evaporated quickly, while others are not suitable. The heating method and the shape of the evaporation source should also be different depending on the evaporation material.

Please visit https://www.sputtertargets.net/by-evaporation-materials.html for more information.

Sputter Coating Advantages vs. Disadvantages

Sputter coating is the core thin film deposition process in the semiconductor, disk drive, CD and optics industries today.

When a suitable gas (usually argon) and a target material (usually metals) are used to form a glow discharge between the cathode and the anode, the sputtering target is bombarded to cause the atoms to be ejected from the target material——the process is referred to as “sputtering”; the atoms of the sputtering target will be deposited on a substrate, such as a silicon wafer, solar panel or optical device, and this process is known as sputter deposition.

Sputter deposition, as a relatively common physical vapor deposition (PVD) method, has its advantages, such as a wide range of deposition materials and high coating quality.

The table below details the advantages and disadvantages of sputter coating. It is provided by Stanford Advanced Materials and is for informational purposes only.

Advantages Disadvantages
(1) Able to deposit a wide variety of metals, insulators, alloys and composites.

(2) Replication of target composition in the deposited films.

(3) Capable of in-situ cleaning prior to film deposition by reversing the potential on the electrodes .

(4) Better film quality and step coverage than evaporation.

(5) This is partly because adatoms are more  energetic, and film is ‘densified’ by in-situ ion bombardment, and it is easier to heat up to high T than evaporation that is in vacuum.

(6) More reproducible deposition control – same deposition rate for same process parameters (not true for evaporation), so easy film thickness control via time.

(7) Can use large area targets for uniform thickness over large substrates.

(8) Sufficient target material for many depositions.

(9) No x-ray damage.

(1) Substrate damage due to ion bombardment or UV generated by plasma.

(2) Higher pressures 1 –100 mtorr ( < 10-5 torr in evaporation), more contaminations unless using ultra clean gasses and ultra clean targets.

(3) Deposition rate of some materials quite low.

(4) Some materials (e.g., organics) degrade due to ionic bombardment.

(5) Most of the energy incident on the target becomes heat, which must be removed.

For more information, please visit https://www.sputtertargets.net/sputtering-target-materials.html.

Image Gallery of SAM Evaporation Materials

High purity evaporation materials play a huge role in deposition processes to ensure high quality deposited film. Stanford Advanced Materials provides various evaporation materials for both thermal and e-beam evaporation, including metal and ceramic boats, filaments, crucibles and heaters, and e-beam crucible liners.

Image Gallery of SAM Sputter Targets

Stanford Advanced Materials (SAM) Corporation is a global supplier of various sputter targets such as metals, alloys, oxides, ceramic materials. We provide sputtering targets for a wide range of applications from ferromagnetic, complex oxides, and semiconducting films.