Yw. Zhang et al., High-fluence Co implantation in Si, SiO2/Si and Si3N4/Si Part II: sputtering yield transients, the approach to high-fluence equilibrium, NUCL INST B, 159(3), 1999, pp. 133-141
The partial sputtering yields of different species from silicon dioxide/Si
and silicon nitride/Si during high-fluence keV Co Metal Vapour Vacuum Are (
MEVVA) irradiation are of importance for both silicide formation and interp
retation of sputter profiling. Three sets of samples, nitride/Si(1 0 0), ox
ide/Si(1 0 0) and oxide/Si(1 1 1), have been bombarded to different normal
fluences, Theta, from 1x10(16) to 2.6x10(18) ions cm(-2). The partial sputt
ering yields for N and Si in the thick nitride films are similar to 1.0 and
similar to 0.65, respectively, which indicates that the relative sputterin
g ratio of N/Si is similar to 1.5. The partial sputtering yields for O and
Si of oxide/Si(1 0 0) samples are determined as similar to 1.0 and similar
to 0.3, respectively. Although the O and Si sputtering yields from oxide/Si
(1 1 1) samples are similar to 15% higher. the average sputtering ratio of
O/Si is similar to 3.4, the same for both sets of oxide/Si samples. As expe
cted, the partial sputtering yield of Co, Y-Co(Theta), is small for low flu
ence implantation and increases with increasing Co fluence. At a normal flu
ence of similar to 5x10(17) ions cm(-2), Y-Co(Theta) reaches the high fluen
ce quasi-equilibrium limit, the value is very close to unity. The sputterin
g yield of Co reduces slightly at even higher fluences, which is associated
with erosion of the sample surface. (C) 1999 Elsevier Science B.V. All rig
hts reserved.