Control of oxidation and reduction reactions at HfSiO∕Si interfaces through N exposure or incorporation

Abstract

Using synchrotron-radiation photoemission spectroscopy, we have investigated oxidation and reduction reactions of HfSiO(N)∕Si gate stack structures annealed in a N2 or O2 atmosphere. It is found that both oxidation and reduction reactions can be suppressed by using nitrogen-incorporated HfSiO films in the annealing process at proper partial pressure of N2 gas (PN2∼100Torr). The detailed analysis of “SiO2 equivalent thicknesses” for annealed HfSiO and HfSiON films reveals that ambient N2 gas suppresses only the reduction reaction, while nitrogen atoms incorporated in dielectrics suppress both oxidation and reduction reactions.