Characterisation of the BaTiO 3/p-Si interface and applications

Abstract

Barium titanate (BaTiO 3), because of its high dielectric constant ( ε r), has proven to be a very promising candidate for use as dielectric layer in ac thin film electroluminescent (ACTFEL) devices and for use in thin film hybrid and integrated circuits. In the present work, BaTiO 3 films were deposited on p-Si (100) substrates by rf-magnetron sputtering at a base temperature of 200°C. The electronic properties of the BaTiO 3/p-Si interface were examined by means of admittance spectroscopy on metal–insulator–semiconductor (MIS) devices fabricated by thermal evaporation of Al. The density of interface states ( D it) was calculated by both the capacitive and the conductive response of the traps; values of the order of 10 12 eV −1 cm −2 were obtained for the D it and values of 10 −5 s were calculated for the relevant time constants of the traps. These values, together with the dielectric constant of the films ranging between 40 and 60, show that the deposited films were suitable for use as cladding insulators in ACTFEL devices.