Evolution of the Si-SiO2 interface characteristics due to preoxidation texturing of silicon surface

Electrical, photoelectrical, and impurity-structural properties of the Si-SiO2 structures formed under the same technological conditions at flat type (FS) and textured (TS) surface regions of silicon wafers were investigated. Enhanced in comparison with FS surface generation velocity, Sg, increased built-in oxide charge density, NsO, and comparatively high differential concentration of interface states, Nss, were obtained with TS. Typical for Pb-centers maximums in Nss(E) spectra at energy position E equals Ec-0.25 eV were observed both for FS and TS samples indicating the participation of silicon atoms with dandling bonds in formation of the Si-SiO2 interface states. Accordingly to SIMS data, the oxide layer at TS was highly contaminated by alkali metals (Na, K) the microstructure of the Si-SiO2 interface being more disordered and 'friable' than in the FS case.