Variable capacitance functions are demonstrated utilizing the transport of Li ions in a simple Pt/lithium phosphorous oxynitride (LiPON)/Pt structure. The capacitance originates mainly from the formation of an electrochemical double layer (EDL) at the interfaces between LiPON and Pt at lower frequencies. Voltage applications drive Li ions from the positively biased electrode to the negatively biased one. At higher voltages, the number of Li ions at the positive electrode decreases to zero, which contributes in making the total EDL capacitance vanish. As a result, the LiPON capacitor exhibits decreased capacitance as the voltage bias is increased, similar to what is observed in a varactor diode. The upper frequency limit of the capacitance variation increases with an increase in the temperature, which seems to be determined by the ionic conductivity of the LiPON matrix. A voltage-controlled oscillator (VCO) operation is also demonstrated by incorporating the LiPON variable capacitors into a resistor–capacitor oscillator circuit. The VCO clearly shows that the oscillation frequency of the output waveforms is exponentially increased with an increase in the input direct current voltage, whose behavior is the same as a varactor diode-based VCO. The results indicate that this ionic variable capacitor can be used as a building block in analog and mixed signal electronic circuits.

中文翻译：

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使用具有薄介电电解质膜的可变电容器的压控振荡器

利用简单的Pt / Li氮氧化锂（LiPON）/ Pt结构中的锂离子传输，证明了可变电容功能。电容主要源自在低频下LiPON与Pt之间的界面处形成电化学双层（EDL）。电压施加将锂离子从正偏压电极驱动到负偏压电极。在较高的电压下，正极的锂离子数量减少到零，这有助于使总EDL电容消失。结果，类似于变容二极管中观察到的，随着电压偏置的增加，LiPON电容器的电容减小。电容变化的上限频率随着温度的升高而增加，这似乎取决于LiPON基质的离子电导率。通过将LiPON可变电容器集成到电阻器-电容器振荡器电路中，还演示了压控振荡器（VCO）的操作。VCO清楚地表明，随着输入直流电压的增加，输出波形的振荡频率呈指数增加，其行为与基于变容二极管的VCO相同。结果表明，该离子可变电容器可用作模拟和混合信号电子电路的基础。VCO清楚地表明，随着输入直流电压的增加，输出波形的振荡频率呈指数增加，其行为与基于变容二极管的VCO相同。结果表明，该离子可变电容器可用作模拟和混合信号电子电路的基础。VCO清楚地表明，随着输入直流电压的增加，输出波形的振荡频率呈指数增加，其行为与基于变容二极管的VCO相同。结果表明，该离子可变电容器可用作模拟和混合信号电子电路的基础。