A new robust capacitance mis-match measurement for analog/mixed-signal applications

This paper presents a new capacitance mis-match measurement method which is more accurate and robust compared to the conventional FGCM method. The resolution of the FGCM method is limited by the parasitics and equipments. In the proposed method, instead of the source node, the voltage on the capacitance is considered as a reference in measurement in order to minimize the effects of pre-existing charge in the floating gate and confirm that the MOSFET is operating in the saturation region. Results of 2-D process and device simulation and the measured data in a 0.13 ¿m process are compared to verify the proposed method. It shows that, compared to the ideal value, the average of the new method are within 0.15% compared to 23.9% in conventional method while the standard deviation is within 0.2%. Also, this method can be easily implemented because the measurement method of Sr and Sm are identical to the conventional method. As a result, using the proposed method, the MIM capacitance can be measured at a much higher resolution than using the conventional method, i.e. to a sub-femto level.