Atomic layer deposition of SiO2 using catalyzed and uncatalyzed self-limiting surface reactions

SiO2 thin films were deposited with atomic layer control using self-limiting surface reactions. The SiO2 growth was achieved by separating the binary reaction SiCl4 + 2H(2)O --> SiO2 + 4HCl into two half-reactions. Successive application of the half-reactions in an ABAB... sequence produced atomic-layer-controlled SiO2 deposition. SiO2 films were grown at temperatures of 600-800 K, with SiCl4 and H2O reactant exposures of similar to 10(9) L (1 L = 10(-6) Torr s). Employing pyridine (C5H5N) as a catalyst, the SiO2 films could be deposited at much lower temperatures and reactant exposures. The pyridine catalyst lowered the required SiO2 deposition temperature from > 600 K to 300 K and reduced the reactant exposure required for complete reactions from similar to 10(9) L to similar to 10(4) L. In addition, the SiO2 grow th rates increased from 0.75 Angstrom per AB cycle at 800 K to 2.1 Angstrom per AB cycle at 300 K. The deposited films were stoichiometric SiO2 and were extremely flat, with a roughness nearly identical to the initial substrate surface. The films also displayed dielectric breakdown strengths similar to thermally deposited SiO2 films. The ability to deposit conformal SiO2 thin films with atomic layer control over a wide range of temperatures should find numerous applications in thin film device fabrication.