高準直性矽奈米尖錐之製備及其特性研究

Abstract

本研究以偏壓輔助微波電漿化學氣相沉積法(Bias assisted microwave plasma enhanced chemical vapor deposition)製備高準直性奈米尖錐結構。本實驗中利用不同的製程參數：針對工作壓力、微波功率、濺鍍金屬、施加偏壓、製程時間的改變來控制奈米尖錐的形狀、大小及密度等性質。並利用掃瞄式顯微鏡(SEM)及穿透式電子顯微鏡(TEM)來對奈米尖錐進行顯微結構的分析，接著利用能量分佈光譜儀(EDS)及歐傑能譜分析(Auger)對奈米尖錐進行定性分析以了解奈米尖錐的組成。 本研究發現利用電漿式乾蝕刻可製備出的高準直性矽奈米尖錐，首先濺鍍金屬作為奈米遮罩(nano-mask)附著在矽奈米尖錐的頂端，在低的工作壓力(1torr)、高負偏壓(-250V)、高微波功率(300W)下可製備出型態理想的高準直性矽奈米尖錐，更可藉著調整製程時間來控制高準直性矽奈米尖錐的尺寸，並藉由研究結果來提出此矽奈米尖錐可能的形成機制。

In this thesis, hydrogen and methane gas mixture is introduced to grow well-aligned silicon nanotips with dry etching in bias assisted microwave plasma chemical vapor deposition. As a result, a new structure with high aspect ratio nanotips is demonstrated. Scanning electron microscopy (SEM) images show great uniformity on size and distribution. Unlike the structure of carbon nanotubes , high resolution TEM images show the solid body of silicon nanotips. Various parameters are introduced to understand the growth mechanism of silicon nanotips. It indicates that the growth of silicon nanotips is analogous to that of carbon nanotubes while sufficient negative bias is essential. I use various parameters like negative bias、work pressure、substrate temperature…..to control the shape of silicon nanotips. To width application, I synthesis well-aligned silicon nanotips with different sputtering metal on top.