Ferroelectric Pb0.92La0.08Zr0.4Ti0.6O3 (PLZT) thin films were deposited on SrTiO3-buffered Si(001) substrate by on-axis radio frequency magnetron sputtering. X-ray diffraction analysis revealed epitaxial growth of monocrystalline PLZT films, with an (001) rocking curve full width at half maximum of similar to 0.3 degrees. phi-scans showed 45 in-plane orientation of the perovskite unit cell relative to that of silicon. The elemental composition of the thin film heterostructure was examined by Auger sputter depth profiling measurements. The recorded profiles suggest that the SrTiO3 buffer layer serves not only as a template for epitaxial growth, but also as a barrier suppressing Pb-Si interdiffusion between the PLZT layer and the Si substrate. The surface roughness of the PLZT layer was measured at similar to 4 nm for films with similar to 500 nm thickness. Wavelength dispersions for the refractive index (n) and the extinction coefficient (k) were obtained from spectroscopic ellipsometry measurements, with n similar to 2.48 at the main communication wavelength lambda = 1550 nm and k<0.001 for lambda>650 nm. Recorded polarization vs. electric field loops for the PLZT epilayer, with a SrRuO3 electrode layer interposed between PLZT and SrTiO3, showed a remnant polarization P-r approximate to 40 mu C/cm(2) and coercive field E-c approximate to 100 kV/cm. These findings suggest that the sputter-deposited PLZT thin films retain the functional properties critical to ferroelectric and electro-optic device applications, also when integrated on a semiconductor substrate.