ATOMIC LAYER DEPOSITION OFSiO2USING CATALYZED AND UNCATALYZED SELF-LIMITING SURFACE REACTIONS

SiO2thin films were deposited with atomic layer control using self-limiting surface reactions. TheSiO2growth was achieved by separating the binary reactionSiCl4+2H2O→SiO2+4HClinto two half-reactions. Successive application of the half-reactions in an ABAB… sequence produced atomic-layer-controlledSiO2deposition.SiO2films were grown at temperatures of 600–800 K, withSiCl4andH2Oreactant exposures of~109L (1 L= 10-6Torr s). Employing pyridine (C5H5N) as a catalyst, theSiO2films could be deposited at much lower temperatures and reactant exposures. The pyridine catalyst lowered the requiredSiO2deposition temperature from 600 K to 300 K and reduced the reactant exposure required for complete reactions from~109L to~ 104L. In addition, theSiO2growth rates increased from 0.75 Å per AB cycle at 800 K to 2.1 Aring; per AB cycle at 300 K. The deposited films were stoichiometricSiO2and were extremely flat, with a roughness nearly identical to the initial substrate surface. The films also displayed dielectric breakdown strengths similar to thermally depositedSiO2films. The ability to deposit conformalSiO2thin films with atomic layer control over a wide range of temperatures should find numerous applications in thin film device fabrication.