雷射光致奈米記錄點於鍺銻碲相變化材料之特性研究

Abstract

本實驗利用雷射光泵探系統(pump and probe laser system)於不同厚度之Ge2Sb2Te5相變化薄膜上寫下記錄點矩陣，欲分析在改變膜層厚度條件下，記錄點之光學反射訊號及表面形貌的改變。實驗中經由以下幾點進行分析：(a)、雷射光探測系統，可藉由光學反射強度進而了解記錄點不同相態(phase state)之改變關係；(b)、透過原子力顯微儀(atomic force microscopy)，可知記錄點表面的形貌(surface topography)起伏與變化，藉此了解雷射光束對相變化材料造成之物理形變為何；(c)、透過導電式原子力顯微儀(conductive-atomic force microscopy)，可知記錄點表面之導電性強弱，藉以分析不同相態之記錄點電性為何；(d)、透過歐傑能譜(Auger electron spectrum)分析，可對樣品表面進行元素成分分析，探討實驗中之表面氧化(surface oxidized)及不連續缺陷區域(defect of surface discontinuity)議題；(e)、透過加熱平台(heating stage)，在加熱下進行原子力顯微儀掃描，可得不同溫度下，寫下記錄點表面變化情形及相變化薄膜電性之改變。

In this study, we first investigate the optical response on phase-change material Ge2Sb2Te5 with an optical pump-probe system (Static tester, Optica co.). From the CCD images and reflectance of recorded mark matrix, the process of recording mark formation and the reflectance change can be analyzed and categorized. An Auger electron spectrum (VG Scientific,Microlab 350.) is also applied to analyze the component and oxidization of different types of recording marks. For further understanding of the phase-change state of recording marks, we use a conductive atomic force microscope (C-AFM) with a heating stage (Asylum Research co.) to investigate the topographic change and the surface current distribution of recording marks on phase-change material at different temperature. From the experimental results, the process and the phase transition of recording marks on phase-change material Ge2Sb2Te5 can be obtained to have the further usage in ultra-high density recording.