Reliability Properties of Rapid Thermal Processed Nitrided Oxides after Fowler-Nordheim Electrical Stress

The reliability properties of RTP nitrided oxides in N2O ambient are investigated and compared with those of reference oxides after Fowler-Nordheim stress. The high quality of the oxinitride layers emphasizes the suitability of this material as an alternative insulator for the fabrication of high performance ULSI devices. Besides, a new method to evaluate the positive interface state charge, which is responsible for the so called turn-around phenomenon in MOS structures, is proposed. The method is based on the combined exploitation of the positive and negative Fowler-Nordheim threshold voltage shifts, ¿Vfn⁺ and ¿Vfn^-, as well as, on the evolution of the threshold voltage ¿Vth obtained on MOS transistors. The major advantage of the technique is that it enables the evaluation of the positive interface charge without any high temperature treatment, contrary to other works.