WNi sputtering targets for electrochromic layers.

Plansee supplies tungsten-nickel sputtering targets for manufacturing the electrochromic layers in smart windows. Our customers use a reactive sputtering process to create the WNi oxide layer from this material. Under normal circumstances, this layer is colorless and transparent. When a DC voltage is applied, inserted lithium ions makes the layer turn blue and thus less transparent.

Sputtering target WNi

Homogeneity and density: Issues to watch with sputtering targets.

Traditional tungsten-nickel targets are manufactured using a thermal spraying process. The disadvantage of this process is that the nickel is not distributed homogeneously and the material density in sputtering targets is generally below 90%. So what does this mean for the customer?

If the nickel is not distributed uniformly, the result is ferromagnetic regions caused by pockets of pure nickel in the material. These have a negative impact on the sputtering behavior and affect the coloring quality of the electrochromic layer.

And the spraying process restricts the possible thickness of the sputtering target to just 5-6 mm. This means that customers have to replace the sputtering targets frequently. In addition, the porosity of a sprayed target can lead to higher particle formation and thin film defects during sputtering. We manufacture our tungsten-nickel sputtering targets using a powder-metallurgical process. From metal powder to the finished product, we handle every step of the process in our own facilities. A density of more than 99.5 % means that it is possible to manufacture sputtering targets with a thickness up to 18 mm. Users can carry on coating for 2-3 times longer than with sprayed targets and no longer have to replace the target so often.

Our manufacturing process results in a particularly homogeneous and dense microstructure . You can see this in this optical microscopy image of a Plansee WNi sputtering target: Pure tungsten (dark gray) in a matrix of WNi compounds. But you cannot find two things, namely free nickel and porosity.

Microstructure tungsten-nickel

However you look at it, the nickel is distributed extremely uniformly across the entire target. The overall nickel content fluctuates by no more than +/- 0.5 percent around the required average value.

The most important properties of our tungsten-nickel sputtering targets
Density (at 20 °C) ≥ 99,5
Purity > 99,97 wt % (3N7)
Homogeneity of nickel distribution < +/- 0,5 wt.%
Nickel content 25 bis 55 wt.%
Microstructure fine-grained, homogeneous

Patent pending.

Patent pending.

We have already applied for a patent on our manufacturing process for WNi sputtering targets.



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Your contact Person for:
Paul Rudnik
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Paul Rudnik