Plasma-assisted atomic layer deposition of conformal Pt films in high aspect ratio trenches

To date, conventional thermal atomic layer deposition (ALD) has been the method of choice to deposit high-quality Pt thin films grown typically from (MeCp)PtMe₃ vapor and O₂ gas at 300 °C. Plasma-assisted ALD of Pt using O₂ plasma can offer several advantages over thermal ALD, such as faster nucleation and deposition at lower temperatures. In this work, it is demonstrated that plasma-assisted ALD at 300 °C also allows for the deposition of highly conformal Pt films in trenches with high aspect ratio ranging from 3 to 34. Scanning electron microscopy inspection revealed that the conformality of the deposited Pt films was 100% in trenches with aspect ratio (AR) up to 34. These results were corroborated by high-precision layer thickness measurements by transmission electron microscopy for trenches with an aspect ratio of 22. The role of the surface recombination of O-radicals and the contribution of thermal ALD reactions is discussed.