The evolution of the HfSiOx/Si interface along with the increase of forming gas annealing temperature

Hafnium silicate-based Metal Oxide Semiconductor (MOS) capacitors were fabricated by atomic layer deposition. The interface evolution of the films with forming gas annealing was investigated. It is found that most of the slow interface states were passivated through Forming Gas Annealing (FGA), and the D_it in the center of the band gap was estimated to be 2.3×10¹¹ eV^-1cm^-2. It is also found that interface layer can react with HfO₂ to form HfSiO_x in the process of FGA at elevated temperature, and the interface thickness was reduced to 0.4 nm after FGA at 600°C.