Determination of physical parameters and reliability of ultra thin oxides

Summary form only given. The aggressive downscaling of CMOS device dimensions requires the fabrication of gate oxides in the 2-3 nm range in the near future. The accuracy and sensitivity of numerous experimental techniques may soon lead to difficulties in measuring physical parameters such as the oxide thickness or the densities of stress induced defects required to quantify oxide degradation and to understand dielectric breakdown. In this presentation, commonly used methods for measurement of oxide thickness were critically reviewed and some recent efforts to obtain higher accuracy for thickness measurements were discussed. Similarly, the limitations of the more conventional methods for defect generation measurement were discussed and one powerful alternative which can only be used in thin oxides was introduced. It was shown how this method, stress induced leakage current measurement, can be related to the oxide degradation and can be used to understand oxide breakdown. The dominant role played by hydrogen in the degradation process was illustrated.