Nickel Ni Evaporation Process Notes
Nickel is a hard, lustrous, silvery-white metal. It has a density of 8.91 g/cc, a melting point of 1,453°C, and a vapor pressure of 10-4 Torr at 1,262°C. Its key characteristics are malleability, ductility, and ferromagnetism and its polished surface resists tarnishing when exposed to air. It is the second most abundant element in earth's core next to iron. It is mainly used to make stainless steel, coins, and batteries. It can also be found in jewelry, but its presence has decreased due to skin allergies. When evaporated in vacuum, nickel can form a decorative coating on ceramic surfaces or a solder layer in circuit device fabrication. It is often sputtered to form layers in the production of magnetic storage media, fuel cells, and sensors.
Nickel Ni Specifications
|Material Type||Nickel †|
|Color/Appearance||Lustrous, Metallic, Silvery Tinge|
|Thermal Conductivity||91 W/m.K|
|Melting Point (°C)||1,453|
|Coefficient of Thermal Expansion||13.4 x 10-6/K|
|Theoretical Density (g/cc)||8.91|
|Max Power Density|
|Thermal Evaporation Techniques||
|E-Beam Crucible Liner Material||FABMATE®‡, Copper|
|Temp. (°C) for Given Vap. Press. (Torr)||
|Comments||Alloys with W/Ta/Mo. Smooth adherent films.|
† Magnetic material (requires special sputter source).
*** Alumina Coated.
* This is a recommendation based on our experience running these materials in KJLC guns. The ratings are based on unbonded targets and are material specific. Bonded targets should be run at lower powers to prevent bonding failures. Bonded targets should be run at 20 Watts/Square Inch or lower, depending on the material.
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.