Extrinsic and Intrinsic Frequency Dispersion of High-k Materials in Capacitance-Voltage Measurements

Abstract

In capacitance-voltage (C-V) measurements, frequency dispersion in high-k dielectrics is often observed. The frequency dependence of the dielectric constant (k-value), that is the intrinsic frequency dispersion, could not be assessed before suppressing the effects of extrinsic frequency dispersion, such as the effects of the lossy interfacial layer (between the high-k thin film and silicon substrate) and the parasitic effects. The effect of the lossy interfacial layer on frequency dispersion was investigated and modeled based on a dual frequency technique. The significance of parasitic effects (including series resistance and the back metal contact of the metal-oxide-semiconductor (MOS) capacitor) on frequency dispersion was also studied. The effect of surface roughness on frequency dispersion is also discussed. After taking extrinsic frequency dispersion into account, the relaxation behavior can be modeled using the Curie-von Schweidler (CS) law, the Kohlrausch-Williams-Watts (KWW) relationship and the Havriliak-Negami (HN) relationship. Dielectric relaxation mechanisms are also discussed.

Advanced high-k gate dielectric amorphous LaGdO3 gated metal-oxide-semiconductor devices with sub-nanometer equivalent oxide thickness

“…The extrinsic frequency dispersion calculated using the relation (C 100kHz -C 1MHz )/C 100kHz was found to be $14% which may be considered to have arisen due to several reasons such as parasitic effects (series resistance arising due to silicon bottom electrode imperfection and cable connection), quantum confinement, presence of interface traps, lossy interfacial layer, and gate leakage current density. 16 The cross-sectional image of one of the heterostructures with $8 nm thick LGO layer studied using HRTEM as shown in Fig. 2(b) revealed a thin structure less IL of thickness $6 Å between the LGO layer and Si substrate that was in good agreement with the deduced value from electrical measurements.…”

Progress in Materials for Microelectronics and Further Challenges

“…Most important, frequency dispersion of the capacitance is observed that is not due to real variations of the relative permittivity of the material with the frequency of the [45], [46], [47]. An effect of charge trapping at the contact between high work function and metal gate high- has been observed [48], [49].…”

Accurate Dielectric Capacitance Determination from MetalInsulator-Semiconductor Devices Having Bias and Frequency Dependent Conductance Due To Leakage Current

“…2 by the parallel capacitance and conductance versus frequency plot at a given bias of 0.5V across a MOS capacitor. The frequency dispersion in accumulation capacitance is a combination of extrinsic and intrinsic effects in the current-voltage characteristics of the MOS capacitor having thermal SiO 2 as the dielectric [8]. The review article of reference [8] separates the extrinsic and intrinsic effects of frequency dispersion in the current-voltage characteristics of the MOS capacitor and also reviews the dielectric relaxation and resonance models pertaining to the intrinsic effects at high frequencies.…”

“…The frequency dispersion in accumulation capacitance is a combination of extrinsic and intrinsic effects in the current-voltage characteristics of the MOS capacitor having thermal SiO 2 as the dielectric [8]. The review article of reference [8] separates the extrinsic and intrinsic effects of frequency dispersion in the current-voltage characteristics of the MOS capacitor and also reviews the dielectric relaxation and resonance models pertaining to the intrinsic effects at high frequencies. The real part of the complex permitivity is due to dielectric relaxation having the nature of permitivity as a function of frequency representing a capacitor, and the imaginary part of the complex permitivity which is due to dielectric resonance is of the nature of σ/ω, where σ is the conductivity of the SiO 2 dielectric and ω is the frequency of the applied electric field.…”