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

SiO2 thin films were deposited with atomic layer control using self-limitin g 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-l ayer-controlled SiO2 deposition. SiO2 films were grown at temperatures of 6 00-800 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 p yridine catalyst lowered the required SiO2 deposition temperature from > 60 0 K to 300 K and reduced the reactant exposure required for complete reacti ons from similar to 10(9) L to similar to 10(4) L. In addition, the SiO2 gr ow th rates increased from 0.75 Angstrom per AB cycle at 800 K to 2.1 Angst rom per AB cycle at 300 K. The deposited films were stoichiometric SiO2 and were extremely flat, with a roughness nearly identical to the initial subs trate surface. The films also displayed dielectric breakdown strengths simi lar to thermally deposited SiO2 films. The ability to deposit conformal SiO 2 thin films with atomic layer control over a wide range of temperatures sh ould find numerous applications in thin film device fabrication.