The influence of the hydrogen ion implantation on the optical parameters of
the SiO2/Si system in relation to results from electrical characterization
is investigated. Theoretical ellipsometric modeling shows that separate sp
ectral regions and proper angles of incidence can be found, where the optic
al parameters of the oxide, interface as well as the Si substrate can be st
udied without high correlation of the respective parameters. From multiple-
angle ellipsometric measurements it is established that the introduction of
hydrogen increases the refractive index and the extinction coefficient of
the Si substrate. This result is linked with the observed increase of the s
ubstrate doping level. The increased refractive index of the oxide upon imp
lantation, and consequently, the mechanical stress, are correlated with ele
ctrically active radiation defects in the interface region. (C) 2000 Elsevi
er Science Ltd. All rights reserved.