RELATIONSHIP BETWEEN PLASMA PARAMETERS AND FILM MICROSTRUCTURE IN RADIO-FREQUENCY MAGNETRON SPUTTER-DEPOSITION OF BARIUM STRONTIUM-TITANATE

Radio frequency magnetron sputtered Ba0.8Sr0.2TiO3 thin films have bee n deposited on silicon and Si/SiO2/SiN/Pt substrates. The analysis of plasma discharge has been carried out using the Langmuir probe techniq ue. Both the pressure and power have been found to influence the ion d ensity and self-bias of the target. Introduction of oxygen into the di scharge effectively decreases the ion density. The structural and elec trical properties have been investigated using x-ray diffraction, atom ic force microscopy of deposited films and capacitance-voltage, conduc tance-voltage, and current density-electric field characteristics of f abricated capacitors. The growth and orientation of the films have bee n found to depend upon the type of substrates and deposition temperatu res. The [100] texture in the film is promoted at a pressure 0.25 Torr with a moderately high value of ion density and low ion bombardment e nergy. Films deposited on Si/SiO2/SiN/Pt substrate have shown higher d ielectric constant (191) and lower leakage current density (2.8 X 10(- 6) A/cm(2) at 100 kV/cm) compared to that on silicon. (C) 1998 America n Institute of Physics.