Optimal frequency range selection for full C-V characterization above 45MHz for ultra thin (1.2-nm) nitrided oxide MOSFETs

We demonstrate a very simple and accurate way to select the proper frequency range in order to achieve full C-V curves with RF test structures. The technique is demonstrated on ultra thin nitrided oxide down to 1.2 nm with very high gate leakage densities (3490 A/cm² at V_GS=2.5 V). For a test structure with high series resistance, the C-V curves are corrected using a two-frequency method (2FT) and show frequency independence, proving the validity of the correction. We also propose a simple calculation to estimate the minimum measurement frequency for given gate oxide thickness and gate area and vice versa.