Jw. Klaus et al., Atomic layer deposition of SiO2 using catalyzed and uncatalyzed self-limiting surface reactions, SURF REV L, 6(3-4), 1999, pp. 435-448
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.