Low temperature deposition of functional thin films on insulating substrates enabled by selective ion acceleration...

Area of Science:

• Materials Science
• Thin Film Deposition
• Plasma Physics

Background:

• Ionized physical vapor deposition (IPVD) techniques like high-power impulse magnetron sputtering (HiPIMS) are advanced but struggle with insulating materials due to difficulties in applying negative potentials for ion acceleration.
• Existing methods like radio frequency biasing for insulators risk damaging films with energetic process gas ions.

Purpose of the Study:

• To introduce and demonstrate Synchronized Floating Potential HiPIMS (SFP-HiPIMS) as a solution for depositing high-quality thin films on insulating substrates.
• To enable selective metal-ion acceleration by utilizing the substrate's transient negative floating potential during HiPIMS discharges.

Main Methods:

• Developed and implemented the Synchronized Floating Potential HiPIMS (SFP-HiPIMS) technique.
• Exploited the transient negative floating potential of the substrate during HiPIMS discharges.
• Timed ion arrival with the negative potential for selective metal-ion acceleration, minimizing energetic Ar+ bombardment.

Main Results:

• Successfully deposited Al0.88Sc0.12N thin films on various insulating substrates using SFP-HiPIMS.
• Observed significant improvements in film crystallinity, texture, and residual stress compared to conventional methods.
• Achieved epitaxial growth of Al0.88Sc0.12N on c-cut sapphire at a low temperature of 100°C.

Conclusions:

• SFP-HiPIMS effectively addresses the long-standing challenge of depositing high-quality films on insulators using ionized physical vapor deposition.
• The technique offers improved adatom mobility and reduced energetic ion bombardment, leading to superior film properties.
• SFP-HiPIMS is versatile, applicable to various materials, and integrates seamlessly with standard deposition equipment.