Effects of post‐deposition annealing of cerium oxide passivation layer in nitrogen‐oxygen‐nitrogen ambient

Abstract

Effects of post-deposition annealing temperature (400°C, 600°C, 800°C and 1000°C) onto metal-organic decomposed cerium oxide (CeO2) precursor spin-coated on n-type Si substrate was carried out in nitrogen-oxygen-nitrogen ambient. The capability of nitrogen to inhibit further oxidation of the Si surface by attaching to the oxygen vacancies sites was reported. Excessive formation of SiO2 interfacial layer however occurred at 1000°C, surpassing the thickness of the CeO2 passivation layer, leaving behind nitrogen dangling bonds that were inefficient in restricting further oxidation of the Si surface, and hence a permanent dielectric breakdown happened at an electric field of 0.98 MV/cm. The CeO2 passivation layer annealed at 800°C broke down at 4.85 MV/cm and possessed relatively low Dit, Qeff, and slow trap density with negligible formation of interfacial layer, which promoted its use as a promising high k passivation layer.