Platinum thin films with good thermal and chemical stability fabricated by inductively coupled plasma-enhanced atomic layer deposition at low temperatures

• Inductively coupled plasma applied to enhance atomic layer deposition (PEALD)
• Smooth Pt films fabricated by PEALD at low temperature
• 8-nm Pt shows clear metal peaks in XPS and XRD.
• 8-nm Pt shows low electrical resistivity of 16 μΩ cm.
• 8-nm Pt shows stability under strong light and pH = 12 wash by NH4+/NaOH solution.

The inductively coupled plasma-enhanced atomic layer deposition (PEALD) method was used to fabricate ultrathin and smooth Pt thin films at low temperatures without the use of a Pt seed layer. The Pt thin metal films deposited at 200 °C onto Si and glass substrates exhibited high conductivities (< 12 μΩ cm for films with a thickness greater than 8 nm) and thermal stabilities resembling those of the bulk material. The measured density of the deposited Pt thin films was 20.7 ± 6 g/cm3. X-ray photoelectron spectra of the films showed clear 4f peaks (74.3 eV (4f5/2) and 71.1 eV (4f7/2)), and X-ray diffraction measurements showed the (111) peak of the fcc structure. The deposited Pt layers were in crystal form. The 25.5-nm Pt films coated onto 170-nm-wide trench structures (aspect ratio of 3.5:1) exhibited good step coverage. The PEALD-deposited Pt thin films were chemically stable under high-temperature light illumination and could serve as catalysts under strongly alkaline conditions (pH = 12) during the long-term oxidization of ammonium ions.