Abstract
Ta2O5, like most insulators, shows complicated current-voltage characteristics depending on the temperature and electric field regime. The temperature dependence of the electrical conduction of Au/ Ta2O5/p-Si (MIS) capacitors is investigated. The measurement temperature ranges from 300K to 523K. From the temperature dependence of the current–voltage characteristics of the Ta2O5 film, it has been suggested that the conduction mechanism is mainly Fowler-Nordheim tunneling through the film at low temperatures (300K∼348K) and high fields (>5MV/cm). The Au/ Ta2O5 potential barrier height jB = 1.25 eV(at 348K)∼1.58 eV (at 300K) was obtained. Poole–Frenkel emission in Ta2O5 film becomes important at higher temperatures (423K∼523K) and high fields (4∼5MV/cm). From fits to the data in the high fields and temperature range, using the expression for Poole–Frenkel emission and taking into account the electric field across the Ta2O5 layer, the dynamic dielectric constant er and the trap level energy jt have been estimated to be 2.18∼2.67 and 1.40∼1.59 eV, respectively. At low fields (< 1MV/cm), electronic ohmic conduction has been observed.