Nickel Sputtering Targets (Ni)

Chapter 2

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Features of Nickel Sputtering Targets

Density: Nickel exhibits a density of approximately 8.91 grams per cubic centimeter, contributing to its overall mass.

Melting Point: The melting point of nickel is relatively high, standing at around 1,455 degrees Celsius, making it suitable for high-temperature applications.

Hardness: Nickel possesses a notable hardness, contributing to its durability and resistance to wear.

Conductivity: As a metal, nickel demonstrates excellent electrical conductivity, making it applicable in various electronic and conductive applications.

Malleability: Nickel is malleable, allowing it to be shaped and molded without breaking, enhancing its versatility in manufacturing processes.

Corrosion Resistance: Nickel is known for its corrosion-resistant properties, making it suitable for applications where exposure to corrosive environments is a concern.

Purity: High-purity nickel targets are often used in sputtering applications, ensuring minimal impurities for precise thin-film deposition.

Compatibility: Nickel is compatible with a range of materials, contributing to its widespread use in various industrial processes.

Oxidation resistance: Nickel has antioxidant properties. A dense oxide film will form on the surface of nickel in humid air at room temperature, preventing the metal from continuing to oxidize, which is beneficial to long-term use.

These characteristics make nickel sputtering targets well-suited for applications in thin-film deposition, electronics, and surface coating processes.

Sputtering Rates

To use these charts, locate the material for which known conditions are available. Then multiply the rate by the relative factors to arrive at the estimated rate for the new material. For example, with previous data showing 3.5A/s aluminum at l00W, then titanium at similar conditions will generate approximately (0.53/1.00) &#; 3.5 Å/s &#; 2 Å/s.

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The rates in this table are calculated based on a 500V cathode potential. As the power is increased greater than two times the original rate, the relative rate will drop slightly (up to 10%). For example, aluminum at 250W.

Al250W = 0.9 &#; AI100W &#; (P1/P0)
0.9 &#; 3.5 Å/s &#; (250/100) &#; 7.4 Å/s

The rates in the ceramics table assume the use of an RF power supply and account for the partial duty cycle of the RF generator as compared to a DC supply. A pulsed DC supply will yield slightly higher effective rates.

The magnetic materials table shows the rate for DC operation with a new target. As the magnetic target erodes, the influence of the remaining material on the magnetic confinement field will change, leading to variations in sputter rate, operation voltage, and ignition pressure.

This information is for general planning purposes only. The Kurt J. Lesker Company makes no guarantees of the correctness of these numbers in your process. Contact the Kurt J. Lesker Company for specific assistance in setting up your process.

NON-MAGNETIC MATERIALS* Material Name Rate Ag Silver 2.88 Al Aluminum 1.00 Au Gold 1.74 Be Beryllium 0.21 C Carbon 0.23 Cu Copper 1.42 GaAs Gallium Arsenide {100} 1.03 GaAs Gallium Arsenide {110} 1.03 Ge Germanium 1.50 Mo Molybdenum 0.66 Nb Niobium 0.76 Pd Palladium 1.77 Pt Platinum 1.00 Re Rhenium 0.84 Rh Rhodium 1.16 Ru Ruthenium 0.98 Si Silicon 0.60 Sm Samarium 1.74 Ta Tantalum 0.67 Th Thorium 1.31 Ti Titanium 0.53 V Vanadium 0.50 W Tungsten 0.57 Y Yttrium 1.53 Zr Zirconium 0.88

* All rates in this table are relative to aluminum.

OXIDES AND CERAMICS Material Name Rate Al2O3 Alumina 0.05 SiC Silicon Carbide 0.22 SiO2 Silicon Dioxide 0.21 Tac Tantalum Carbide 0.09 Ta2O5 Tantalum Pentoxide 0.39 MAGNETIC MATERIALS Material Name Mag Moment Rate Co Cobalt Low 0.73 Cr Chromium Med 0.87 Fe Iron High 0.57 Mn Manganese Med 0.14 Ni Nickel Low 0.86 Ni80Fe20 Permalloy High 0.80

There are a few ways that you can increase/ maximize the sputtering rate of materials;

1. Increase power: While each material will be limited in their max power relative to their material properties, the cooling efficiency will allow you to operate the target at the highest possible power density. The first thing you should do is directly cool the target material by utilizing either a bolt-on style or bonded target configuration. This in addition to the aid of a conductive paste or epoxy will maximize the thermal conductivity and allow you to increase the power density to the maximum level attainable by the target material.

2. Decrease source-substrate distance: The closer the target to the substrate, the higher the sputtering rate will be. Generally, the plasma will be contained within 2" above the target surface. Many sputtering applications utilize a 3"-4" source-substrate distance. Assuming a 4" source-substrate distance, the sputtering rate will fall off by approximately 25% for every inch beyond 4". However, the rate will typically increase by approximately 35% for every inch closer you go from 4" away.

3. Lower operating pressures: In sputtering, the more gas in the chamber, the more atom and ion collisions there will be. These collisions will reduce the rate at which material atoms eject from the target surface and deposit onto the substrate. By reducing the operating gas flow, these collisions will be reduced and will have a positive impact on the ultimate sputtering rates that can be achieved.

4. Increase the number of magnetrons in the chamber: Rates will scale linearly by the number of magnetrons that are added to your application. In production applications with specific yield requirements, once the power and source-substrate parameters have been fully maximized, increasing the number of magnetrons is a parameter that can be utilized to enhance sputtering rates.

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