Aurelio Pellegrini

Analysis of conductivity degradation in gold/platinum-doped silicon

A general model is presented, describing the effects of gold/platinum doping in silicon. The steady-state case is then analyzed with reference to the conductivity degradation due to deep impurities in realistic cases of n- and p-type materials. In particular, the different influence of gold with respect to platinum in n-type material, due to the localization in energy of the two acceptor levels, is quantitatively explained and reproduced.

Dynamic modeling of amorphous- and polycrystalline-silicon devices

The materials of which thin-film transistors (TFTs) are fabricated are characterized by a large amount of defects, giving rise to localized states with a complex energy distribution within the gap. As a consequence, the electrical characteristics of TFTs are difficult to model analytically, and a numerical approach may be preferred to predict their performance. A new efficient method is presented to solve the time-dependent semiconductor equations accounting for energy-distributed gap states. Applications are provided to the analysis of realistic devices and inverters.

AC analysis of amorphous silicon devices

The transport model in semiconductors is examined in the case where the effect of distributed gap states is significant like, e.g., in thin-film transistors. A solution scheme is derived for the two additional continuity equations accounting for the trapped charge such that, without loss of generality, the efficiency of the traditional method implemented in the existing device-analysis codes is kept. The dynamic effect of the trapped charge is then examined in the ac operation of a realistic thin-film device, including the analysis of the interelectrode capacitances.