Atomic Layer Deposition of SiO₂ Thin Films Using Tetrakis(ethylamino)silane and Ozone

We examined the atomic layer deposition (ALD) of silicon dioxide thin films on a silicon wafer by alternating exposures to tetrakis(ethylamino)silane [Si(NHC₂H₅)₄] and O₃. The growth kinetics of silicon oxide films was examined at substrate temperatures ranging from 325 to 514 °C. The deposition was governed by a self-limiting surface reaction, and the growth rate at 478 °C was saturated at 0.17 nm/cycle for Si(NHC₂H₅)₄ exposures of 2 × 10⁻⁶ L (1 L = 10⁻⁶ Torr·s). The films deposited at 365–404 °C exhibited a higher deposition rate of 0.20–0.21 nm/cycle. However, they contained impurities, such as carbon and nitrogen, and showed poor film qualities. The concentration of impurities decreased with increasing substrate temperature. It was found that the films deposited in the high-temperature regime (478–514 °C) showed excellent physical and electrical properties equivalent to those of LPCVD films.