Yj. Cho et al., Ellipsometric examination of optical property of the Si-SiO2 interface using the s-wave antireflection, J APPL PHYS, 85(2), 1999, pp. 1114-1119
Using variable-angle spectroscopic ellipsometry and introducing two models
(a three-phase and a two-film model), we examined the optical properties of
thermally grown SiO2 layers on Si, with special focus on phase difference
Delta and amplitude ratio tan psi for the s and p waves. We found an abrupt
flip of the cos Delta curve from which the s and p-wave antireflection con
ditions were determined and evaluated the interface sensitivities for cos D
elta and tan psi based on the three-phase (ambient-oxide substrate) and the
two-film (ambient-oxide-interlayer substrate) model. The sensitivities for
cos Delta and tan psi were shown to have maximum values at the same angle
of incidence and photon energy in the s-wave antireflection condition. By f
itting the variable-angle spectroscopic ellipsometry data measured in the s
-wave antireflection condition, the thickness of the Si-SiO2 interface was
determined as 0.784+/-0.003 nm for a 52-nm thick oxide sample and 0.764+/-0
.002 nm for a 150-nm-thick oxide one. We also found that the effective refr
active index of the interface was 2.060 at 546 nm for the 52 nm sample and
1.981 for the 150 nm sample, respectively. (C) 1999 American Institute of P
hysics. [S0021-8979(99)02602-X].