Investigation of Rapid Thermally Nitrided-SiO_2/Si Interface with Conductance Technique
利用电导技术研究快速热氮化二氧化硅与硅界面的性质

The device-quality SiO_2 films with a thickness of 15 nm have been nitrided in NH_3 byrapid thermal processing technique.The properties of the interface between these films andSi substrate were investigated by conductance technique using a measurement system equippedwith precision lock-in amplifier. The results show that the nitridation increases the densityand time constant of interface states,enhances the fluctuation of surface potential, but chang-es the hole capture cross-section only slightly.Especially, nitridation introduces a peak of in-terface states at 0.25 eV below midgap and the energy dependency of hole capture cross-sec-tion is suppressed. Using a patchwork model, the surface potential fluctuation can be well si-mulated and a surface charge nonuniformity with a long-way length distribution may exist.These are consistent with the fact that nitridation induces a high oxide charge density.Theexperimental data show that all these properties depend on nitridation time and temperature.