Precise Control of Nitrogen Profiles and Nitrogen Bond States for Highly Reliable N[sub 2]O-Grown Oxynitride

Abstract

Gate dielectrics formed by oxynitridation using a rapid thermal annealer (RTA) and a furnace were developed and evaluated. The oxynitrides formed by RTA show very large time‐to‐breakdown () values and small stress‐induced leakage current, as compared with pure oxides and oxynitrides formed by furnace annealing. The depth profile of the peak for oxynitfides was analyzed by X‐ray photoelectron spectroscopy. Nitrogen atoms in the oxynitrides formed by RTA are localized at the interface. and those in the oxynitrides formed during furnace annealing exist uniformly throughout the film. The differences in nitrogen bond state in the oxynitride between the RTA and the furnace are due to the decomposition of gas. A nitrogen atom at the interface bonds with one oxygen and two silicon atoms , or bonds with three silicon atoms . A nitrogen atom located in the bulk of the film, however, bonds with two oxygen atoms and one silicon atom . We clarified that the electrical and chemical characteristics of the oxynitride depend on the location of gas decomposition. Thus, precise control of the nitrogen profile and the nitrogen bond states is very important for the formation of highly reliable oxynitride. © 2000 The Electrochemical Society. All rights reserved.