奈米線蕭特基二極體於生醫感測研究

Abstract

本論文利用電子束微影研製矽奈米線，並利用此結構製作出水平式之奈米線蕭特基二極體生物感測器。在考量與現存微電子製程的配合下，本研究選用鎳矽化物(Nickel-silicide)做為金屬/半導體蕭特基二極體之金屬部分。將對鎳矽化物進行一系列材料分析、討論，包含X射線光電子光譜(X-ray photoelectron spectrum, XPS)、穿透式電子顯微鏡 (transmission electron microscope, TEM)、掃描式電子顯微鏡 (scanning electron microscope, SEM)、拍攝晶格繞射圖案(diffraction pattern)、元素成分分析(EDX)等。此外，本研究利用自組裝技術(Self-assembly technique)在元件表面修飾AEAPTMS與帶負電金奈米粒子、Biotin-Streptavidin來測試元件之分子感測靈敏度。當表面接上不同之帶電分子時，將形成類似上閘極(top gate)之結構，進而影響元件之電流電壓特性。由實驗結果得知，在元件表面修飾AEAPTMS與帶負電金奈米粒子或是Biotin-Streptavidin，蕭特基二極體之導電度皆明顯改變。金屬/半導體蕭特基二極體元件表面修飾對載子傳輸之影響與估計亦在本論文中探討。無論從實驗與實作來看，蕭特基二極體確實為一高靈敏度之生物分子感測元件，在未來應可成為超越場效電晶體之生物感測器元件。

In this thesis, both the silicon process and e-beam lithography were adopted to fabricate the nanowire Schottky diodes. First, we discuss the formation of NiSi/Si Nanowire heterostructure. Characterization of the nickel silicide, including its cross-sectional image, the atomic ration of Ni to Si, and the structure of the crystal are included. Second, electrical properties of the nanowire Schottky diodes were explored. The I–V characteristics of the silicon nanowire with NiSi/Si schottky contact are measured at different gate bias voltage over the temperature range from 260 K to 340 K. After that, discussion on the conduction mechanism of molecular gated-effect in Schottky diode was presented. Finally, the sensitivity of nanowire Schottky diode in molecular detection using the AEAPTMS-gold nanoparticles and Biotin-Streptavidin systems were discussed. The change of conductance in surface modifications of AEAPTMS-GNPs and Biotin-Streptavidin systems are both obviously greater than those of SiNW-FET. It is believed that the Schottky diode will transcend the field-effect transistor in molecular detection in the future.