ATOMIC LAYER DEPOSITION OF SiO2 USING CATALYZED AND UNCATALYZED SELF-LIMITING SURFACE REACTIONS

Abstract

SiO 2 thin films were deposited with atomic layer control using self-limiting surface reactions. The SiO 2 growth was achieved by separating the binary reaction SiCl 4+ 2H 2 O → SiO 2+ 4HCl into two half-reactions. Successive application of the half-reactions in an ABAB… sequence produced atomic-layer-controlled SiO 2 deposition. SiO 2 films were grown at temperatures of 600–800 K, with SiCl 4 and H 2 O reactant exposures of ~109 L ( 1 L = 10-6 Torr s). Employing pyridine ( C 5 H 5 N ) as a catalyst, the SiO 2 films could be deposited at much lower temperatures and reactant exposures. The pyridine catalyst lowered the required SiO 2 deposition temperature from 600 K to 300 K and reduced the reactant exposure required for complete reactions from ~109 L to ~ 104 L. In addition, the SiO 2 growth 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 stoichiometric SiO 2 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 SiO 2 films. The ability to deposit conformal SiO 2 thin films with atomic layer control over a wide range of temperatures should find numerous applications in thin film device fabrication.