Effect of substrate pretreatments on the atomic layer deposited Al2O3 passivation quality

The authors show here that the passivation quality of Al 2O3 is highly sensitive to the surface condition prior to the atomic layer deposition, affecting especially the thermal stability of the film. Pretreatments like diluted HCl bath or preheating at 200°C both improved significantly the passivation quality and thermal stability of the films. In addition, the authors observed that a thin chemical SiO2 layer resulting from diluted HCl solves the blistering problem often encountered in H2O based atomic layer deposited process. Finally, the authors show that the chemical oxide protects the surface from contaminants, enabling long storage times in a dirty ambient between the cleaning and the film deposition.