INFLUENCE OF PLASMA TREATMENT CONDITIONS ON GROWTH AND ELECTRICAL-PROPERTIES OF OXIDES ON INP

Plasma treatments are playing an increasing role in microelectronic technology. The present paper deals with the deposition of Ta2O5 dielectric layers on n-InP by multipolar plasma technology for the fabrication of MISFET (metal insulator-semiconductor field effect transistor) structures. Damage induced by plasma exposure is one of the major problems in such fabrication. Therefore the working conditions (sample bias, discharge power and oxygen pressure) have to be optimized so as to limit the ion energy on the substrate during treatment. After plasma treatment the oxide films are stabilized by post-annealing at 200-degrees-C in an N2 atmosphere. The oxide thickness is determined by ellipsometric measurements. The growth condition of the dielectric in the plasma is also related to the basic electronic and interface properties of InP-oxide-Au structures using static I-V, dynamic C-V and ESCA (electron spectroscopy for chemical analysis) measurements. Equivalent Schottky barriers as high as 0.87 eV are obtained.