以掃描探針顯微鏡在鈦金屬薄膜上進行氧化加工之研究

Abstract

本實驗中利用掃描穿隧顯微鏡（STM）及原子力顯微鏡（AFM）在鈦（Ti）薄膜表面成長鈦氧化物。實驗中主要以三種不同的掃描探針顯微術進行研究，包括接觸式AFM，Lift Mode 搭配接觸式AFM及STM，所有的實驗均在大氣環境中進行；最後並以接觸式AFM氧化加工工字形鈦膜，並量測其通道兩端氧化加工前後電流與電壓關係的變化。實驗結果顯示，進行氧化加工時的電壓值、掃描速度、探針掃描高度（對Lift Mode而言）以及穿隧電流值（對STM而言），皆為影響氧化結果的重要參數。以氧化效率而言，接觸式AFM與Lift Mode AFM相似，STM最差；以加工穩定性而言，接觸式AFM則優於其他二者。工字形鈦膜經氧化加工後，室溫下電阻值可由104 提高至108∼109 。本實驗亦討論STM探針的製備方法，並嘗試以自製STM探針作為STM氧化加工之用。

This work studies the fabrication of oxide patterns on titanium (Ti) thin films using scanning probe microscopy (SPM). We employed three different scanning probe microscopy techniques, namely, AFM in contact mode, lift mode incorporated with contact mode AFM, and STM. All experiments carried out in atmospheric ambient. We also adopted contact mode AFM to anoxidize the I-shaped Ti thin film. It was found that bias voltages, scanning speed, scanning height of the probe (for lift mode), and setpoint current (for STM) play important roles in forming the attainable oxide features. For the efficiency of oxidation, contact mode AFM was similar to lift mode incorporated with AFM, but better than STM. As to the patterning stability, contact mode AFM was better than other two methods. The resistance of I-shaped Ti thin film after anoxidization raised from 104 to 108∼109 which evidenced the occurrence of oxidation in Ti. We also studied the method for STM tips preparation and employed them to STM anoxidization.