10 things you should know about high power impulse magnetron sputtering (HiPIMS)

1. In HiPIMS the power is applied in pulses of low duty cycle leading to high peak power during the pulse on time while cooling the target during the pulse off time avoiding thereby target overheating.

2. The peak power density is the range of few kW.cm-2 compared to few W.cm-2 in conventional magnetron sputtering (dcMS).

3. As a result, the plasma density is 3 orders of magnitude higher than that in dcMS which significantly increases the ionization probability by electron impact allowing the ionization of the sputtered species.

4. The ionization fraction of the sputtered species is a function of the target material and the peak power at the target. The ionization fraction is low for elements with low electron impact ionization cross-section (σi) and high ionization potential (IP) such as carbon (4.5%), but high for element with high (σi) and low (IP) such as titanium (90%).

5. It is possible to increase the ionization fraction for materials such as carbon by increasing the pulse length which is especially desirable for DLC coating deposition to increase the content of sp3 bonding.

6. The high ionization degree leads to high ion flux towards the growing film which enhances the coating properties while avoiding argon atoms sub plantation resulting from flux made of argon ions accompanied by high bias voltage.