ULTRATHIN TA2O5 FILM GROWTH BY CHEMICAL-VAPOR-DEPOSITION OF TA(N(CH3)(2))(5) AND O-2 ON BARE AND SIOXNY-PASSIVATED SI(100) FOR GATE DIELECTRIC APPLICATIONS
Ka. Son et al., ULTRATHIN TA2O5 FILM GROWTH BY CHEMICAL-VAPOR-DEPOSITION OF TA(N(CH3)(2))(5) AND O-2 ON BARE AND SIOXNY-PASSIVATED SI(100) FOR GATE DIELECTRIC APPLICATIONS, Journal of vacuum science & technology. A. Vacuum, surfaces, and films, 16(3), 1998, pp. 1670-1675
Citations number
35
Categorie Soggetti
Physics, Applied","Materials Science, Coatings & Films
We investigated Ta2O5 films grown by chemical vapor deposition of Ta(N
(CH3)(2))(5) and O-2 both bare and SiOxNy-passivated Si(100) using x-r
ay photoelectron Spectroscopy, time-of-flight secondary-ion-mass spect
roscopy (TOF-SIMS), and electrical measurements. The SiOxNy-passivated
layer was formed by nitric oxide exposure to the Si substrate. Chemic
al composition of the Ta2O5 films is strongly dependent on the oxygen
flow rate during film deposition; lower carbon levels and higher O/Ta
ratios are observed for the films grown at higher O-2 flow rates. A co
rresponding leakage current decrease is observed for the films grown a
t a high O-2 flow rate. Compared to Ta2O5 films deposited on bare Si(1
00), the films deposited on SiOxNy-passivated layers show better elect
rical properties; with smaller equivalent thickness (Delta t(eq) simil
ar to 6 Angstrom) one order of magnitude lower leakage current was mea
sured. TOF-SIMS data indicate that SiOxNy layers (similar to 9 Angstro
m) incorporate some oxygen during Ta2O5 deposition; however, regions w
here x=2, y=0 were not detected. Postdeposition annealing of Ta2O5/SiO
xNy samples results in displacement of N by O in SiOxNy layers and oxi
dation of the Si substrate, forming SiO2. (C) 1998 American Vacuum Soc
iety.