PREPARATION AND PROPERTIES OF TA2O5 FILMS BY LPCVD FOR ULSI APPLICATION

Preparation and electrical properties of tantalum pentoxide (Ta205) films have been studied for the application to ultra large scale integrated circuits (ULSIs). Ta205 films were deposited by a cold wall-type low-pressure chemical vapor deposition (LPCVD) at temperatures of 340°–400°C, and then annealed at temperatures ranging from 600° to 900°C in O2. It can be found that for the films grown by the present method, a high-temperature annealing is exceedingly effective for an increase in dielectric constant and a decrease in leakage current flowing through the film. Relative dielectric constants of 25–35 are achieved for the annealed Ta205 films with the thickness above 40 nm, which are about 1.4 times larger than those reported previously. The annealing forms a transition oxide layer at the Ta2Os-Si interface, which results in excellent C-V characteristics of metal-insulator-semiconductor (MIS) capacitors as applied to ULSI. © 1990, The Electrochemical Society, Inc. All rights reserved.