具液態閘極控制並以側壁遮罩法製備之奈米線感測器

Abstract

於本篇論文中，我們以側壁遮罩法(Sidewall Mask Technology)製作矽奈米線元件，將元件作為感測器的應用，並藉由液態閘極(Liquid-Gate)的控制以提高感測靈敏度。透過側壁遮罩法的製程，我們利用傳統的黃光微影技術，搭配圖案反轉(image reversal)、SU8平坦化及側壁遮罩的最佳參數，製成品質良好的奈米線陣列。當奈米線尺寸微縮後，在相同大小的感測區域內可提高奈米線密度，進而增加量測靈敏度。 完成奈米線製程後，我們做pH酸鹼溶液的量測。首先，將元件視為一個電阻(resistor)，在滴上不同pH值的酸鹼溶液後，量奈米線兩端金屬電極之間的電流-電壓特性曲線(I-V curve)。接著，在pH溶液中放入一端電極，形成液態閘極(Liquid-Gate)的架構，量測其電性變化趨勢，並針對施加液態閘極的延遲時間和積分時間對元件特性的影響做測試。最後，計算出酸鹼響應度，兩端點電阻式靈敏度為31%⁄pH，而加上液態閘極後靈敏度獲得大幅提升至55%⁄pH，我們分析其中的原理與變化趨勢，再與文獻上的結果做比較。

In this paper, we adopt Sidewall Mask Technology for fabricating silicon nanowire devices, applying these devices as sensors, and enhancing their sensitivity through the control of a liquid gate. By employing the sidewall mask process, we utilize conventional photolithography, coupled with image reversal, SU8 planarization, and optimized sidewall masking parameters to produce high-quality nanowire arrays. By reducing the dimensions of the nanowires, we increase the density within the same sensing area, thereby enhancing the measurement sensitivity. After completing the nanowire fabrication, we conducted measurements in pH solutions. Initially, we treated the device as a resistor, measuring the current-voltage (I-V) characteristics of the nanowires after applying various pH solutions. Subsequently, we placed one electrode in the pH solution to create a Liquid-Gate configuration and measured the electrical property trends. We also investigated the effects of the delay and integration times of applying the liquid gate on the device characteristics. Finally, we calculated the pH response ratio, the endpoint resistive sensitivity was 31% per pH, which significantly increased to 55% per pH with the control of the liquid gate. We analyze the underlying principles and trends of these changes and compare them with results from the literature.