利用射頻濺鍍系統製成碲化錳鎘薄膜及其物理特性研究

Abstract

本論文為利用雙磁控濺鍍鎗射頻濺鍍系統在II-VI 族半導體碲化鎘（CdTe）薄膜中摻雜具磁性之 "Mn"原子 , 使之成為稀磁性半導體（DMS）薄膜 , 並探討其物理特性 . 首先在製程上 , 兩支濺鍍鎗分別安裝 "碲化鎘" 及 "碲化錳" 靶材 , 藉由濺鍍功率及鍍膜壓力大小來精確控制其摻雜錳離子的濃度 , 並透過鍍膜時間、溫度及原真空室內退火（in-situ post annealing）時間、溫度來精確控制最佳鍍膜參數 , 以便製成出具高方向性結構的薄膜 . 其次 , 在物理特性量測與分析上 , 利用X光繞射儀（XRD）來測得薄膜的晶體結構及其方向性 ; 利用能量散射分析儀 （EDAX）來分析薄膜成份 ; 利用場發射式掃瞄電子顯微鏡（FESEM）來獲得薄膜晶粒大小與表面型態 ; 利用光穿透光譜（Transmission）量測來獲得薄膜能隙Eg 的大小 ; 利用拉曼光譜量測來獲得碲化錳鎘薄膜的縱向與橫向光支聲子的振動模式 .

The diluted magnetic semiconductor Cd1-xMnxTe thin films were fabricated by R.F.Sputtering system. Its physical properties were studied in this thesis. Firstly , we used dual gun sputtering deposition technique to fabricate the high oriented Cd1-xMnxTe thin films and adjusted the Mn concentration precisely by controlling the sputtering power and deposition pressure. We obtained the optimum temperature of deposition and the period of in-situ post annealing. Secondly , on characterizing the physical properties , the crystallinity , structure and orientation of these films the x-ray diffraction(XRD) is used.The compositions of the thin films were determined by the energy dispersive analysis of x-ray (EDAX). The surface morphology and grain sizes were obtained by a field emission scanning electron microscopy (FESEM). The energy gap Eg of the thin films was estimated from the transmission spectrum. The LO and TO mode behaviors of the Cd1-xMnxTe thin films were investigated by micro Raman spectra for thin films with various Mn concentrations .