奈米碳管與鈀金屬之接觸阻抗研究

Abstract

奈米碳管有著優異的電性特質使其於奈米科技應用上備受期待，但奈米碳管與金屬間之接觸阻抗會對於奈米碳管電晶體之電性有極大的影響，本論文即著重於如何改善奈米碳管與鈀金屬之接觸阻抗之相關研究。 鈀金屬與氧化矽介電層之附著力不佳，本實驗利用氮化矽當作介電層來改善鈀金屬與基版間之附著力。 本論文採用四端點方式量測接觸阻抗。一開始鈀與碳管間之接觸阻抗很高，相關文獻表示，因碳管與金屬間之存有奈米空隙，經由實做得知6000C退火可改善此問題而降低接觸阻抗。 我們藉由高解析度穿透式電子顯微鏡得知奈米碳管管壁上有著電晶體製作過程中所造成之吸附物，我們挑選了幾種前處理製程，化學濕式前處理與化學電漿前處理，了解各種前處理製程對於電性的影響。利用高解析度穿透式電子顯微鏡發現6000C可以去除碳管管壁上之附著物。我們採用拉曼分析了解到長時間超音波震盪製程會對碳管造成損傷，也得知高能離子與強氧化劑會對碳管造成一定之破壞。

Carbon nanotubes (CNTs) have excellent electrical properties making them attractive for applications in nanotechnology, The contact resistance between CNT and metal has significant influence on the electrical performance of CNT field effect transistors. This thesis focus on how to improve contact resistance. Palladium deposited on SiO2 surface shows poor adhesion. We use SiN film to improve the adhesion between Palladium and substrate. In the measurement aspect, four terminal method is employed to measure contact resistance. At first, we find high contact resistance. It’s due to the nano void between metal and CNTs. The problem can be solved after annealing at 600oC. High Resolution Transmission Electron Microscope (HRTEM) micrographs show a amorphous layer which because of devices process covering the CNTs. Two kinds of methods include Chemistry liquid treatments and Chemistry Plasma treatments are selected to find out the influence of these treatments. Upon 600oC annealing, the amorphous layer is removed. The facts are seen in HRTEM. Raman analysis show CNTs were damaged by excess ultrasonic oscillation process. Raman analysis also show the high energy ions and the strong oxidant can create the certain destruction to the CNTs.