The Best Balance of Oxygen Flow and Deposition Rate to Give Little Absorption of Aluminum Oxide Film Deposited by Electron Beam Evaporation Technique

摘要

The effects of deposition rate and oxygen flow rate on refractive index of aluminum oxide film are investigated. The Al2O3 films are deposited by electron beam technique on glass substrate at different deposition rates and oxygen flow rates. Substrate is heated to reach 300 °C and the temperature is kept constant during the thin film growth. Then, using the maxima and minima of transmittance, the index of refractive and the extinction coefficient of samples has been determined. It has been found that the index of refractive increase if we reduce the oxygen flow while keeping the deposition rate the same. Hardness is also increased with the decrease in the O2 flow rate. At some low oxygen flow, the extinction coefficient is small and therefore the Al2O3 films have some absorption.