Reliability of ultra-thin N2O-nitrided oxides grown by RTP under low pressure in different gas atmospheres

The reliability of oxynitrides with thicknesses from 4.0 nm down to 2.6 nm. was investigated. The oxynitrides were grown by rapid thermal processing a t reduced pressure in gas atmospheres of N2O, a 50% mixture of N2O and O-2, and O-2. The concentrations of the nitrogen incorporated into the oxide du ring growth were found to be dependent on both, oxidation pressure and oxid ation atmosphere. Reliability tests were performed by constant voltage stre ss on MOS capacitors. The measurements revealed that oxynitridation in N2O containing ambient can improve reliability even for oxides thinner than 3 n m. The nitrogen concentration, which is beneficial to oxide reliability, sh ows strong dependence on oxide thickness. (C) 2001 Elsevier Science Ltd. Al l rights reserved.