Characterization of Al2O3 and SiO2 ultra thin-films deposited by ALD for microfabricated rubidium vapor cells

Abstract

The Atomic Layer Deposition (ALD) technique can be used to increase the lifetime of microfabricated rubidium vapor cells (magnetic sensors for magnetoencephalography) by an ultra-thin coating layer deposited on the internal cell walls (Figure 1). The ALD presents excellent control over the ultra thin films thickness (< 20 nm) and allows complex 3D structures to be covered with a high-aspect-ratio coating. This work shows the characterization of alumina (Al2O3) and silicon dioxide (SiO2) ultra-thin films deposited by Thermal ALD (ThALD) and Plasma-Enhanced ALD (PEALD).