Al2O3 ultra-thin films deposited by PEALD and ThALD for rubidium optically pumped atomic magnetometers

Abstract

[Excerpt] The Atomic Layer Deposition (ALD) technique can be used to improve the rubidium optically pumped atomic magnetometers (OPMs) cell lifetime with a conformal deposition of Al2O3 ultra-thin film on the internal cell walls as a protective coating avoiding the disappearance of the alkaline metal vapor over time. In this work, 10 nm thick Al2O3 ultra thin-films by ThALD and by PEALD were deposited and compared. Trimethylaluminium (TMA) and pure water (H2O) were used as the precursors for ThALD, whereas TMA and O2-plasma were used for the PEALD avoiding oxidation by H2O. The Al2O3 ultra-thin films were deposited at the same ALD reactor by a SENTECH system.