深能階暫態譜儀系統之設計與裝置

　　　　　在半導體材料中若有缺陷存在，則半導休與構成元件之特性將會嚴重地受到影響 。所以今日的半導體技術研究上．缺陷的偵測已成為重要的課題。深能階暫態，兵識義系統 (Deep Level Transient Specuoscopy; DLTS) 能夠偵測缺陷之諸多參數，例如活化能， 捕 捉截面，激發速率，陷阱濃度之空間分佈與接面特性。為了提高偵測速率，降低人為取樣與 分析誤差，並且增加資料的儲存量與提高精確度與可靠度，自動化測量定必需的。在此論文 中，我們提出深能階暫態譜儀系統之測試原理與裝置設計，並且使用電腦程式自動化控制來 測試 N 型砷化鎵金局氧化物半導體 (MOS) 元件得其缺陷之活化能為 0.636eV 及其捕捉截 面為 3.06*10-14 cm ?插C 由圖譜中峰值位置之遷移，我們可獲得此元件介面缺陷能態之濃 度分佈。傳統的 DLTS 技術必須浪費許多時間在熱掃描過程中，因此使用多速率窗與多脈波 之單一熱掃描法將在本論文中介紹。
　　　　　The existence of defect states should affect the characteristics of semiconductors and devices. For example, the measurement of defect statesis the most important process in the research on semiconductor technique.The technique of deep level transient spectroscopy (DLTS) is proposed tomeasure the parameters of defect states, such as the activation energy, thecapture crosssection, the emmission rate, the concentration profile and theinterface states. In order to obtain the high measured speed, reduce themanual sampling and analytic errors, enhance the reliability and accuracy of data and increase the storage of data, automatic measurement method must beused. The theory and construction of DLTS are proposed in this paper. The characteristics of the traps of an N-type GaAs MOS diode were measured byour automatic program. Its active energy was 0.363eV and the capture crosssection was 3.06*10'@ cm@. Because of the shift of peaks in the DLTS spectrum, we could understood that it belongs to the interface states. The traditional DLTS measurement wastes so much time in thermal scanning to get the parameters. Hence, a single thermal scanning with multirate windows and multi-pulse biases is introduced in this paper to reduce theprocessing time.