High-density transition layer in oxynitride interfaces on Si(100)

Nitrided SiO2 thin films on Si wafers were studied by x-ray reflectivity me asurements and their electron-density profiles were evaluated. Interfacial layers of the oxides were found to have densities higher than that of eithe r crystalline Si substrates or strained interfacial layers of thermal oxide s. The high density probably results from nitrogen incorporation near the i nterfaces. The present results suggest that strongly retarded boron penetra tion through nitrided gate oxides is due to their high-density interfacial layers. (C) 1999 American Institute of Physics. [S0003-6951(99)00950-X].