Step by step rare-earth catalyzed SiOx annealing and simultaneous formation of Europium- silicide by low coverage of Eu doped Gd₂O₃ nanoparticles

We report the formation of silicide by annealing of a SiO_x surface, with low coverage of Eu doped Gd₂O₃ nanoparticles. The annealing temperature required for removal of native oxide from the Si substrate decreases with close to 200 °C in presence of the nanoparticles. X-ray photoemission electron microscopy, low-energy electron microscopy and mirror electron microscopy are used to monitor the silicide formation and SiO_x removal. Fragmentation of the nanoparticles is observed, and the SiO_x layer is gradually removed. Eu migrates to clean Si areas during the annealing process, while Gd is found in areas where oxide is still present. This annealing process is clearly facilitated in the presence of rare-earth based nanoparticles, where nanoparticles are suggested to function as reaction sites to catalyze the oxygen removal and simultaneously form Eu based silicide. Reduction of the annealing temperature of SiO_x substrates is also observed in presence of pure Eu³⁺ and Gd³⁺ ions. Simultaneous oxygen removal and EuSi formation enable this new rare-earth catalyzed annealing and silicide formation to find applications both within optoelectronics and processing microelectronic industry.