<p>This study presents a comprehensive impedance spectroscopy (IS) analysis of Au/Ti/AlN/n-Si metal–oxide semiconductor (MOS) structures, with the aim of elucidating their dielectric and interfacial properties under different bias and frequency conditions. The real (<InlineEquation ID="IEq1"> <EquationSource Format="TEX">${Z}{\prime}$</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi>Z</mi> <mo>′</mo> </mrow> </math></EquationSource> </InlineEquation>) and imaginary (<InlineEquation ID="IEq2"> <EquationSource Format="TEX">${Z}^{{\prime}{\prime}}$</EquationSource> <EquationSource Format="MATHML"><math> <msup> <mrow> <mi>Z</mi> </mrow> <mrow> <mo>′</mo> <mo>′</mo> </mrow> </msup> </math></EquationSource> </InlineEquation>) components of impedance were measured across 100 Hz–1 MHz and DC biases between 1 and 4 V, and the data were modeled using an equivalent circuit composed of a series resistance (<InlineEquation ID="IEq3"> <EquationSource Format="TEX">${R}_{s}$</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>R</mi> <mi>s</mi> </msub> </math></EquationSource> </InlineEquation>), a parallel resistance (<InlineEquation ID="IEq4"> <EquationSource Format="TEX">${R}_{p}$</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>R</mi> <mi>p</mi> </msub> </math></EquationSource> </InlineEquation>), and a parallel capacitance (<InlineEquation ID="IEq5"> <EquationSource Format="TEX">${C}_{p}$</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>C</mi> <mi>p</mi> </msub> </math></EquationSource> </InlineEquation>). The impedance spectra revealed a clear capacitive-to-resistive transition, while Cole–Cole plots consistently exhibited a single semicircle, confirming the presence of a unique relaxation mechanism. Relaxation times (<i>τ</i>), extracted both from <InlineEquation ID="IEq6"> <EquationSource Format="TEX">${Z}^{{\prime}{\prime}}$</EquationSource> <EquationSource Format="MATHML"><math> <msup> <mrow> <mi>Z</mi> </mrow> <mrow> <mo>′</mo> <mo>′</mo> </mrow> </msup> </math></EquationSource> </InlineEquation>–f peaks and <InlineEquation ID="IEq7"> <EquationSource Format="TEX">${R}_{p}\bullet {C}_{p}$</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <msub> <mi>R</mi> <mi>p</mi> </msub> <mo>∙</mo> <msub> <mi>C</mi> <mi>p</mi> </msub> </mrow> </math></EquationSource> </InlineEquation> fitting, showed excellent agreement and demonstrated bias-dependent evolution, with accelerated relaxation at moderate bias and slower dynamics at higher bias due to trap saturation. Notably, <InlineEquation ID="IEq8"> <EquationSource Format="TEX">${C}_{p}$</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>C</mi> <mi>p</mi> </msub> </math></EquationSource> </InlineEquation> remained nearly constant across all biases, while <InlineEquation ID="IEq9"> <EquationSource Format="TEX">${R}_{p}$</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>R</mi> <mi>p</mi> </msub> </math></EquationSource> </InlineEquation> varied systematically, reflecting the influence of interfacial states. The analysis of normalized interface trap density further indicated progressive trap passivation with increasing bias, underscoring the stability of the AlN/Si interface. These findings validate the equivalent circuit model and highlight AlN as a promising dielectric material for high-frequency, low-leakage MOS applications, offering predictable relaxation behavior and reduced trap activity compared to conventional high-k dielectrics.</p>

Equivalent circuit modeling and relaxation dynamics of Au/Ti/AlN/n-Si MOS structures

期刊论文
出版模式：

开放获取
发表日期：

2026年1月12日

查看全文

Aysel Büyükbaş-Uluşan,
Adem Tataroğlu,
Abdullah Karaca,
Dilber Esra Yıldız

摘要

This study presents a comprehensive impedance spectroscopy (IS) analysis of Au/Ti/AlN/n-Si metal–oxide semiconductor (MOS) structures, with the aim of elucidating their dielectric and interfacial properties under different bias and frequency conditions. The real ( ${Z}{\prime}$ $Z'$ ) and imaginary ( ${Z}^{{\prime}{\prime}}$ $Z^{''}$ ) components of impedance were measured across 100 Hz–1 MHz and DC biases between 1 and 4 V, and the data were modeled using an equivalent circuit composed of a series resistance ( ${R}_{s}$ $R_{s}$ ), a parallel resistance ( ${R}_{p}$ $R_{p}$ ), and a parallel capacitance ( ${C}_{p}$ $C_{p}$ ). The impedance spectra revealed a clear capacitive-to-resistive transition, while Cole–Cole plots consistently exhibited a single semicircle, confirming the presence of a unique relaxation mechanism. Relaxation times (τ), extracted both from ${Z}^{{\prime}{\prime}}$ $Z^{''}$ –f peaks and ${R}_{p}\bullet {C}_{p}$ $R_{p} ∙ C_{p}$ fitting, showed excellent agreement and demonstrated bias-dependent evolution, with accelerated relaxation at moderate bias and slower dynamics at higher bias due to trap saturation. Notably, ${C}_{p}$ $C_{p}$ remained nearly constant across all biases, while ${R}_{p}$ $R_{p}$ varied systematically, reflecting the influence of interfacial states. The analysis of normalized interface trap density further indicated progressive trap passivation with increasing bias, underscoring the stability of the AlN/Si interface. These findings validate the equivalent circuit model and highlight AlN as a promising dielectric material for high-frequency, low-leakage MOS applications, offering predictable relaxation behavior and reduced trap activity compared to conventional high-k dielectrics.