Role of interfacial nitrogen in improving thin silicon oxides grown in N2O

Abstract

We have used chemical depth profiling, with a depth resolution of 10 Å, in conjunction with x-ray photoelectron spectroscopy to study the composition and chemical bonding in thin silicon oxides grown in N2O with both a conventional furnace and a rapid thermal annealer (RTA) process. The nitrogen profiles of RTA and furnace oxides differ, with the RTA oxides showing an increase in nitrogen concentration at the interface and the furnace oxides showing a more uniform nitrogen distribution. The percentage of nitrogen at the interface also differs, and correlates with a reduction in interface state generation under current injection for increased nitrogen concentration. The chemical environment for the nitrogen changes with distance from the interface, and this is attributed to an increasing number of nitrogen—silicon bonds near the interface.