Hydrogen annealing effect on the properties of thermal Ta2O5 on Si

The effect of post-metallization annealing in H-2 at 723 K on the propertie s of MOS capacitors with thermally grown thin (13-26 nm) Ta2O5 layers was i nvestigated. It was established that the annealing effect strongly depends on the properties of the as-grown oxides and in particular on the oxidation temperature. The oxidation at higher temperatures (823 and 873 K) is benef icial for improving the electrical, breakdown and insulating properties of the films after annealing. A dielectric constant of 32 was reached for thes e layers and the magnitude of leakage current guarantees their application in 64 Mbit DRAM. The hydrogen annealing, however, additionally generates sl ow states in the oxide with a density of about 5 x 10(11) cm(-2). (C) 1999 Published by Elsevier Science Ltd. All rights reserved.