EFFECTS OF ELECTRIC-FIELD ON PHOTOCONDUCTIVE FREQUENCY RESOLVED SPECTROSCOPY - ANALYSIS OF SILICON-ON-INSULATOR STRUCTURES

A room temperature analysis of the excess carrier recombination kinetics and lifetime has been made by photoconductive frequency resolved spectroscopy (PCFRS) technique on silicon-on-insulator structures obtained by single and multiple oxygen implants. In all cases PCFRS spectra show an exponential recombination mechanism, characterized by a single lifetime, which is strongly influenced by the applied electric field. The analysis of the field dependence has allowed us to determine the excess carrier lifetime tau and to estimate the ambipolar mobility mu(a). According to these measurements, the top (Si) layer from these structures is characterized by high values of excess carrier lifetime (20-115-mu-s). The linearity of the recombination process confirms the good electrical quality of the Si layers. The simplicity of the used spectrometer and the straightforward interpretation of the data suggest PCFRS being an easy tool directly applicable to the electrical characterization of complex multilayered structures such as SOI.