多晶矽奈米線薄膜電晶體之研製與應用於酸鹼感測器之研究

Abstract

我們成功的發展出一套簡單與低成本的技術，來製作奈米線場效電晶體。藉由此種元件，我們可以得到一個接近理想狀態的酸鹼感測器(57.1mV/pH)。此外，我們可以不需藉由任何額外的外接電路，即可觀測出酸鹼溶液所造成的即時電性變化，同時，此項元件還能多次重覆使用。 另外，我們也比較了奈米線與一般的平面場效電晶體電特性上的差異，以及感測的敏感度表現。我們發現，相較於傳統電晶體的次臨界擺幅(1333 mV/dec)，奈米線改進的幅度相當大(297 mV/dec)。此外，對於感測器方面，奈米線所產生的電流敏感度(12.78%/pH)也比傳統電晶體(5.46%/pH)的表現為好。而這些特性也間接證明了本實驗室所製作出的奈米元件特性優異，非常適合用於感測器方面。

In this thesis, we’ve successfully developed a simple and low-cost method to fabricate thin film transistors with nanowire channels. By employing the fabricated devices equipped with a SiO2 sensing pad for pH sensing application, a high sensitivity (57.1mV/pH) is obtained, which is close to the ideal value (60mV/pH). Besides, real-time drain current response corresponding to the variation of pH value in the test solution is demonstrated without using any external circuit. Reproducibility of such capability is also confirmed in this work.

We’ve also investigated and compared the basic and pH sensing characteristics of the nanowire structures and conventional planar devices. The subthreshold swing of the nanowire structures (297 mV/dec) is much better than that of the planar ones (1333 mV/dec). Furthermore, the current response sensitivity of nanowire (12.78%/pH) is also better than that of the planar (5.46%/pH) one. These characteristics evidence the superiority of the nanowire device for sensor application.