Atomic layer deposition of B 2O 3 thin films at room temperature

Abstract

Atomic layer deposition of boron oxide thin films was demonstrated at room temperature using BBr 3 and H 2O as precursors. Crystallinity of the films was characterised by X-ray diffraction while time-of-flight elastic recoil detection analysis (TOF-ERDA) and X-ray fluorescence were used to analyse stoichiometry and possible impurities. As-deposited films were amorphous and reacted readily with the atmosphere if not protected by an alumina overlayer. Boron oxide deposition rate of 0.76 Å per cycle was obtained at 20 °C. If the deposition temperature was increased to 50 °C and above, almost no film growth could be obtained. According to the TOF-ERDA, hydrogen and carbon contents in the films were very low being less than 0.2 and 0.1 at.%, respectively.