Aluminum (Al) Wire Overview
We sell these pellets and pieces by unit weight for evaporation use in deposition processes. These approximate materials prices are published to provide budgetary guidelines. Actual prices can vary and may be higher or lower, as determined by availability and market fluctuations. To speak to someone directly about current pricing, please click here .
Aluminum (Al) General Information
Aluminum is one of the most common metals in the world. It can be found in kitchen utensils, cars, street lights, and the popular aluminum foil food packaging. Aluminum is a silvery-white, metallic material. It is light, malleable, ductile, and non-magnetic under normal conditions. It has a density of 2.7 g/cc, a melting point of 660°C, and a vapor pressure of 10-4 Torr at 1,010°C. Although it is not a strong material, it is a good conductor of heat and electricity and is able to form an oxide layer that is resistant to corrosion. Due to its high reactivity, it is rarely found in nature as a free element. When evaporated in a vacuum, aluminum layers form a reflective coating found on telescopes, automotive headlamps, mirrors, packages, and toys. It is widely used in the aerospace, automotive lighting, OLED, and optical industries.
Aluminum (Al) Specifications
Material Type | Aluminum |
Symbol | Al |
Atomic Weight | 26.9815386 |
Atomic Number | 13 |
Color/Appearance | Silvery, Metallic |
Thermal Conductivity | 235 W/m.K |
Melting Point (°C) | 660 |
Coefficient of Thermal Expansion | 23.1 x 10-6/K |
Theoretical Density (g/cc) | 2.7 |
Z Ratio | 1.08 |
E-Beam | Excellent |
Thermal Evaporation Techniques |
Basket: W Crucible: TiB2-BN, BN |
E-Beam Crucible Liner Material | FABMATE®, Intermetallic |
Temp. (°C) for Given Vap. Press. (Torr) |
10-8: 677 10-6: 821 10-4: 1,010 |
Comments | Alloys W/Mo/Ta. Flash evap or use BN crucible. |
Suggested QCM Crystal | Gold Crystal: KJLCRYSTAL6-G10**** |
**** Suggestion based on previous experience but could vary by process. Contact local KJLC Sales Manager for further information
Empirical Determination of Z-Factor
Unfortunately, Z Factor and Shear Modulus are not readily available for many materials. In this case, the Z-Factor can also be determined empirically using the following method:
- Deposit material until Crystal Life is near 50%, or near the end of life, whichever is sooner.
- Place a new substrate adjacent to the used quartz sensor.
- Set QCM Density to the calibrated value; Tooling to 100%
- Zero thickness
- Deposit approximately 1000 to 5000 A of material on the substrate.
- Use a profilometer or interferometer to measure the actual substrate film thickness.
- Adjust the Z Factor of the instrument until the correct thickness reading is shown.
Another alternative is to change crystals frequently and ignore the error. The graph below shows the % Error in Rate/Thickness from using the wrong Z Factor. For a crystal with 90% life, the error is negligible for even large errors in the programmed versus actual Z Factor.
Thermal Evaporation of Aluminum (Al)
It is important to note that aluminum has the tendency to alloy with refractory metals causing cracks in metal crucibles and boats during e-beam or thermal evaporation.
Here are two methods for thermally evaporating aluminum.
One approach is to use a thin width, thick gauge, high current tungsten boat such as our EVS20A015W. We have been successful with evaporating aluminum in this particular boat and are able to deposit more than 3,000 angstroms per run with rates greater than 30 angstroms per second. We are able to get multiple runs (about 4) with two 1/4" X 1/4" pellets in the boat during each run. Generally, the current draw from the boat is quite consistent run-to-run. It is crucial not to disturb the boat when venting the chamber to re-load with more pellets as the boat becomes brittle after the first evaporation. Even though the boats will need to be replaced frequently (a thicker boat only prolongs inevitable cracking), they are usually inexpensive. However, down-time experienced while switching out the boats should be considered when using this method.
The second recommendation is to use a shielded tantalum crucible heater with a tall intermetallic crucible. Intermetallic crucibles are composed of titanium boride (TiB2) and boron nitride (BN). This material combination works well with aluminum because the material is both lubricious and electrically conductive. The crucible is both strong and conductive, yet its lubricious properties prevent material spill-over and crucible cracking. Great care must be taken when installing the heater to prevent the outer shields from becoming warped which can cause a short in the heater, causing the welded joints to fail. The heater should be centered between the contacts and the outer shielding must be clear of the leads.
Some of our production customers have indicated they can get 10-15 runs out of intermetallic crucibles. These users are very experienced in thermally evaporating aluminum in high volumes. Therefore, they have refined their processes so it is possible that these results may not be typical in all applications. An example of a heater-crucible set-up would be our EVCH1 or EVCH10 paired with EVC9INTSPL01 when using one of our vacuum systems.
Flash evaporation of aluminum is a common method of depositing large amounts of aluminum, especially in the automotive lighting and decorative industries. Pieces of aluminum (wire, canes, coils, etc.) are inserted onto tungsten filaments. The filaments are connected to electrical feedthroughs and, when sufficient current is applied, the aluminum instantaneously (flash) evaporates. There are generally many filaments connected in a deposition system, allowing for a large number of substrates to be coated simultaneously. It should be noted that not all 100% of the aluminum evaporates. A portion "wets" the tungsten and over several runs, the filament will break and need to be replaced.
Crucibles should be stored in a cool, dry place and always handled with gloves or forceps.
E-beam Evaporation of Aluminum (Al)
It is important to note that aluminum has the tendency to alloy with refractory metals causing cracks in metal crucibles and boats during e-beam or thermal evaporation.
As with thermal evaporation, we recommend using an intermetallic crucible when e-beam evaporating aluminum because of the crucible material's unique conductive and lubricious characteristics. A key process note is to consider the fill volume in the e-beam application because we find that the melt level of aluminum in the crucible directly affects the success of the crucible liner. Overfilling the crucible will cause the material to spill over and create an electrical short between the liner and the hearth. The outcome is cracking in the crucible. This is the most common cause of crucible liner failure. Placing too little material in the crucible or evaporating too much material before refilling can be detrimental to the process as well. When the melt level is below 30%, the e-beam is likely to strike the bottom or walls of the crucible which immediately results in breakage. Our recommendation is to fill the crucible between 2/3 and 3/4 full to prevent these difficulties. While our customers report success in running aluminum out of intermetallic crucibles, others claim that FABMATE® crucibles last longer. It is important to mention that most FABMATE crucibles are less expensive than intermetallic crucibles.
There is a risk of aluminum carbide contamination in films if higher powers are used during evaporation. High beam power causes increased thermal load on the crucible and carbon from the liner can infiltrate the aluminum melt. Evidence of this occurrence is generally a transparent, yellowish film that covers the surface of the melt. The evaporation rate will plummet and the natural reaction is to increase the power. However, this only exacerbates the problem. Applying lower beam powers from the beginning of the process will help to minimize this threat.
Crucibles should be stored in a cool, dry place and always handled with gloves or forceps.
See highlighted results that match your result in the table below.
Ordering Table
Material | Description | Size | Quantity | Purity | Part Number | Price | In Stock | Add To Cart | |
---|---|---|---|---|---|---|---|---|---|
Material | Description | Size | Quantity | Purity | Part Number | Price | In Stock | Add To Cart | |
Aluminum |
ALUMINUM WIRE, |
1.0 mm (0.040") Dia. | 1 ft. | 99.99% | EVMAL40040 | $4.00 | |||
Aluminum |
ALUMINUM WIRE, |
1.0 mm (0.040") Dia. | 100 m | 99.999% | EVMAL50040 | $405.00 | |||
Aluminum |
ALUMINUM WIRE, |
1.0 mm (0.040") Dia. | 50 ft. | 99.999% | EVMAL5004050FT | $178.00 | |||
Aluminum |
ALUMINUM WIRE, |
1.0 mm (0.040") Dia. | 1 ft. | 99.999% | EVMAL50040FT | $5.00 | |||
Aluminum |
ALUMINUM WIRE, |
1.5 mm (0.060") Dia. | 1 lb. | 99.99% | EVMAL40060 | P.O.R. | |||
Aluminum |
ALUMINUM WIRE, |
1.5 mm (0.060") Dia. | 1 lb. | 99.999% | EVMAL50.062 | $843.00 | |||
Aluminum |
ALUMINUM WIRE, |
2.0 mm (0.080") Dia. | 10 m | 99.999% | EVMAL502MM+ | P.O.R. |