MOS capacitor measuring method based on five-element model

Abstract

The invention provides an MOS capacitor measuring method based on a five-element model. The MOS capacitor measuring method comprises the steps of: establishing a five-element equivalent circuit model of an MOS capacitor; adopting a two-element parallel model for carrying out C-V measurement and I-V measurement on the MOS capacitor at two different frequencies; extracting an auxiliary characteristic equation of the MOS capacitor according to the five-element equivalent circuit model and measurement results; and solving the auxiliary characteristic equation to obtain a capacitance value of the MOS capacitor. The MOS capacitor measuring method is applied to an MOS structure of a non-dispersive dielectric, the obtained reasonable MOS capacitance does not change along with the two selected frequencies (namely, non-dispersive), other four elements have reasonable numerical values, and the reasonability and self-consistency of the MOS capacitor measuring method based on the five-element model are shown.

Description

technical field [0001] Embodiments of the present invention relate to the field of MOS capacitance measurement, in particular to a MOS capacitance measurement method based on a five-element model. Background technique [0002] Accurate measurement of the capacitance of the MOS structure is very important, especially the capacitance of the accumulation region. The capacitance of the MOS accumulation region corresponds to the capacitance of the gate dielectric layer, and the dielectric constant and thickness of the gate dielectric can be determined according to the capacitance of the gate dielectric layer. It is impossible to accurately measure the MOS capacitance by directly using the two-element parallel connection model or series connection model. Such as figure 1 The frequency dispersion of the MOS capacitance measured directly by the parallel model shown is too large, and the measurement results are as follows figure 2 As shown, the frequencies are 100kHz, 200kHz, 400...

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Problems solved by technology

The solution obtained by using this model often still has a large dispersion, and more importantly, there will be an unreasonable negative inductance value (very close to 0), which shows that it is unnecessary to consider the inductance value in the measured frequency range

The second model considers the MOS capacitance (C) and the series resistance (R s ) on the basis of the interfacial layer capacitance (C i ) and interfacial layer resistance (R i ),like Figure 5 shown, but ignore the parallel resistance of the MOS capacitor (R p )

[0006] Neither the three-element model nor the four-element model can give a reasonable solution for the MOS structure with an interface layer, because three or four elements are not enough to simulate a MOS device with an interface layer in the gate.

Ignoring the interface layer will affect the accuracy and even rationality of the measurement results

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