Effects of chemical composition on the electrical properties of NO-nitrided SiO2

• DOI: 10.1063/1.113244
• Publication Date: 2002-07-26T13:39:01Z
• Authors: M. Bhat; L. K. Han; D. Wristers; J. Yan; D. L. Kwong; J. Fulford
• Keywords: 02 engineering and technology; 0210 nano-technology

The impact of nitrogen (N) concentration and distribution on the electrical and reliability properties of rapid-thermally NO-annealed oxides is studied. The use of NO-annealing of thermally grown SiO2 provides an excellent way to isolate the effects of N, since this method allows for the incorporation of varying N profiles in the oxide without a simultaneous increase in dielectric thickness. Results show that the electrical properties of the dielectric under gate and substrate Fowler–Nordheim injection are highly sensitive to the N profile in the dielectric. While interface endurance (ΔDit) is seen to improve monotonically with increasing N concentrations for both +Vg and −Vg, the same is not observed for charge-to-breakdown (QBD) properties. It is found that although QBD improves with NO nitridation under +Vg, it shows a turnaround behavior under −Vg, i.e., for a 10-s NO-annealed oxide the QBD value is improved over control oxide while further nitridation is seen to degrade QBD under −Vg. The presence of bulk N and the nonuniform N distribution in the dielectric is responsible for this behavior.