Accuracy and applicability of low-frequency C-V measurement methods for characterization of ultrathin gate dielectrics with large current

Relatively low-frequency (< 3 MHz) capacitance-voltage measurement methods are quantitatively analyzed on their accuracy and applicability by both simulations and experiments for measuring ultrathin gate dielectrics with large leakage current. The effect of parasitic originates from the chuck stage of the measurement system is taken into account in the discussion. A novel technique is developed that can reduce the parasitic effect by modifying the conventional four terminal pairs configuration. Simulations and experimental results of the capacitance measurement revealed that the LC resonance method is the most competitive measurement method among the three-element equivalent circuit analysis methods in the low-frequency regime. The experimental results of LC resonance method are compared to those of the high-frequency-measurement (similar to 1 GHz) method and shown to be robust up to small signal MOS resistance of 1.5 x 10(-3) Omega. cm(2) at which dc leakage current equal to 4.6 x 10(2) A/cm(2). Last, the applicability range of the low-frequency-measurement methods for measuring ultrathin dielectric films is proposed by utilizing the parallel resistance to the MOS capacitor as the index parameter.