CHARACTERISTICS OF BATIO3 THIN-FILMS ON SI DEPOSITED BY RF MAGNETRON SPUTTERING

Thin films of BaTiO3 were deposited on single-crystal Si using rf mage ntron sputtering. Different microstructures resulted from varying the substrate temperature during sputtering or from post-annealing after f ilm deposition. High trap and surface state densities at the interface between BaTiO3 and Si were found for the films deposited at room temp erature even though such films showed a relatively low leakage current and a high breakdown voltage. These surface states or traps, neverthe less, could be partially annealed out of the film at a temperature aro und 450 degrees C. High deposition temperatures above 600 degrees C in troduced unrecoverable surface states at the interface. BaTiO3 thin fi lms that were deposited at a substrate temperature in the range 450-50 0 degrees C gave the best performance in terms of their electrical and interface properties. BaTiO3 thin-him capacitors with a configuration of Au/BaTiO3/p-Si/Al, fabricated with optimized BaTiO3 thin-him depos ition conditions, showed a value of the dielectric constant near 30, a leakage-current density as low as 10(-7) A cm(-2) at a held intensity of 2 x 10(5) V cm(-1), a breakdown voltage above 10(6) V cm(-1) and a n interface state density of around (4-6) x 10(11) eV(-1) cm(-2).