Atomic Layer Deposition and Properties of Silicon Oxide Thin Films Using Alternating Exposures to SiH2Cl2 and O3

We report the process for the atomic layer deposition (ALD) of silicon dioxide thin films on a silicon wafer by alternating exposures to SiH2Cl2 and O3. The growth kinetics of silicon oxide films was examined by varying reactant exposures at various deposition temperatures ranging from 250 to 450 °C. The deposition was governed by a self-limiting surface reaction, and the growth rate at 350 °C was saturated at 0.25 nm/cycle for SiH2Cl2 exposures of over 5×109 L (10-6 Torr·s). The chlorine content and the wet-etching rate in a diluted HF solution were reduced by increasing the deposition temperature. The films deposited at temperatures ranging from 350 to 450 °C exhibited excellent physical and electrical properties that were equivalent to those of silicon oxide films deposited at 760 °C by low-pressure chemical vapor deposition.