[论文解读] Frequency dependent dielectric properties of Al/ maleic anhydride (MA) /p-Si structures

Sema Bi̇lge Ocak, A. Birkan Selçuk+2 more|arXiv (Cornell University)|Oct 5, 2015

Semiconductor materials and interfaces参考文献 8被引用 6

一句话总结

本研究调查了通过旋涂法制备的Al/马来酸酐/p-Si肖特基结构的频率与电压依赖性介电特性。结果表明，介电常数随频率增加而急剧下降，介电损耗在电压依赖下出现显著跃迁，且在低频时界面极化效应占主导，表明界面态对耗尽区和累积区介电偏离有显著贡献。

ABSTRACT

Al/ maleic anhydride (MA) /p-Si organic Schottky devices were fabricated on a p-Si semiconductor wafer by spin coating. The frequency and voltage dependent dielectric constant of Al/MA/p-Si have been investigated. Dielectric properties and electrical conductivity of contact structures have been investigated in detail by using spectroscopic technique in a wide range of frequencies and applied bias voltages at room temperature. The values of dielectric constant, dielectric loss, dielectric loss tangent, real and imaginary parts of the electrical modulus and ac electrical conductivity were found considerably sensitive to frequency and applied bias voltage especially in depletion and accumulation regions. Experimental results indicate that the values of dielectric constant show a steep decrease with increasing frequency for each voltage. The values of dielectric loss as a function of voltage show a jump, and dielectric loss decreases with decreasing voltage and increasing frequency. The weak increasing of the ac electrical conductivity on frequency is observed. The real part of electric modulus increases with increasing frequency. Also, the imaginary part of electric modulus shows a peak and the peak position shifts to higher frequency with increasing applied voltage. It can be concluded that the interfacial polarization can be more easily occurred at low frequencies and the majority of interface states at metal semiconductor interface contributes to deviation of dielectric properties of Al/MA/p-Si structures.

研究动机与目标

• 分析基于Al/MA/p-Si的有机肖特基二极管的介电特性在频率与电压依赖下的行为。
• 研究界面极化与界面态在改变介电响应中的作用。
• 量化在不同频率与偏置电压下介电常数、介电损耗、损耗正切、电导率模量和交流电导率。
• 通过室温下的光谱技术理解耗尽区与累积区的电学行为。

提出的方法

• 通过在p-Si晶圆上旋涂马来酸酐制备Al/MA/p-Si结构。
• 利用光谱技术在宽频率范围和不同偏置电压下测量介电特性。
• 从介电数据计算电导率模量的实部与虚部，以分析弛豫过程。
• 从阻抗谱数据中提取介电常数、介电损耗、损耗正切和交流电导率。
• 分析频率与电压依赖性，以识别极化机制与界面态贡献。
• 在室温下进行测量，以排除热效应影响，隔离本征介电行为。

实验结果

研究问题

• RQ1 Al/MA/p-Si结构的介电常数如何随频率与外加电压变化？
• RQ2 界面极化在Al/MA/p-Si肖特基结构介电响应中起什么作用？
• RQ3 金属-半导体结处的界面态如何影响介电特性？
• RQ4 Al/MA/p-Si体系中交流电导率的频率依赖性如何？
• RQ5 电导率模量行为如何反映体系中的弛豫动力学？

主要发现

• 在所有外加电压下，介电常数随频率增加而急剧下降。
• 介电损耗在低电压下出现尖锐跃迁，且随频率增加和电压降低而减小。
• 电导率模量的实部随频率增加而增大，表明弛豫过程增强。
• 电导率模量的虚部显示峰值，且随着外加电压增加向更高频率移动。
• 随着频率增加，交流电导率呈现微弱增加。
• 界面极化在低频时最为显著，且界面态对耗尽区与累积区介电偏离有显著贡献。