Advanced broadband monitoring for thin film deposition through equivalent optical admittance loci observation

A monitoring technique using the equivalent optical admittance loci of thin films to control the deposition is presented. Real-time broadband spectrum measurements are employed to extract the real-time thin film refraction index and thickness, and the corresponding equivalent optical admittance is thereby obtained. This monitoring method can predict the termination point of the deposition process and avoid the termination ambiguities, which generally appear with other broadband monitors. Compared to other monitoring methods, the experimental results of the proposed monitoring technique show better error compensation ability.