1.5 - nm -thick silicon oxide gate films grown at 150°C using modified reactive ion beam deposition with pyrolytic-gas passivation

Abstract

Low-temperature ultrathin silicon oxide gate film growth using modified reactive ion beam deposition (RIBD) with an in situ pyrolytic-gas passivation (PGP) method is described. RIBD uses low-energy-controlled reactive and ionized species and potentializes low-temperature film growth. By combining RIBD with PGP using N2O and NF3, 1.5-nm-thick silicon oxide gate films with high-potential barrier height energy, 3.51eV, and low-leakage current, less than about 10−5A∕cm2 at 2MV∕cm, can be obtained at a growth temperature of 150°C. From an evaluation of number densities of N, F, and O atoms near the 1.5–5.0-nm-thick RIBD-with-PGP silicon oxide films/Si(100) interfaces, it is believed that interfacial N and F atoms contribute to improve the electrical characteristics and F effectively compensates the residual inconsistent-state bonding sites after the N passivation.