Abstract
在本論文中,我們利用Tsuprem4和Medici軟體去建立一個完整的流程,詳細地去分析光二極體與電荷耦合元件間連結區域的電性及傳輸特性;其分析著重於小位能井障礙,讀取方式,讀取電壓,還有本體和界面缺陷.在電壓波形方面,利用真實的輸入電壓實際去模擬整個暫態分析;利用設定電子準費米電位來空乏之前儲存在位能井中的電子.我們模擬分析了光二極體與電荷耦合元件間傳送的效率和電子在儲存於電荷耦合元件期間,受本體與界面缺陷的影響.透過整個分析與模擬,我們可以找出在何種條件下的結構才是最好的設計.在傳送訊號的過程中,光二極體與電荷耦合元件間連結區域形成一小位能井障礙,由於它阻擋了許多電子的傳輸,造成傳輸效率的低落,並大大地影響了此結構的實用性.我們發現,增加電荷耦合元件的濃度,降低光二極體n-型的濃度和縮短傳送路徑,都將有利於電荷的傳送.雖然增加電荷耦合元件濃度,不但有利於電荷的傳送,且增加了最大電荷載子容量,但卻嚴重了本體結合效應.降低了光二極體n-型的濃度,卻又降低了光二極體的最大載子容量.若是結構已被固定,增加讀取電壓將會減少傳輸損失.在本體缺陷方面,我們發現,較少的缺陷密度,較長的缺陷時間常數和缺陷能量較靠近導通帶,都有助於減少電荷的損失.但缺陷時間常數通常與缺陷能量的位置息息相關,更增加了其複雜度.至於在界面缺陷方面,雖然界面缺陷有助於電荷的傳送,但卻增加了電荷被捕捉的機率.In this thesis, the electrical properties of the linking areabetween photodiodes ans charge coupled devices are analyzedbased on the considerations of the formation of a small well,read-out through surface channel, read-out by punchthroughmechanism, read -out pulse, and bulk and interface traps. Anelectron quasi-fermi potential is set to deplete initialstorage wells under transient analysis. Through this transientsimulation, we calculated the charge loss in differentconditions during charge transfer periods. The processsimulation was built such that through Tsuprem4 andMedici simulations we can construct a whole procedurefor charge transfer. This prediction is important, becausewe can decide a better structure with less time and lesssilicon try out. The transfer loss due to a small well barrierexisted between the photodiode and the CCD is particularlystudied. The transfer loss is reduced, even approaching zero,when the CCD peak doping becomes heavier and the n-diode regionof the photodiode beneath interface becomes narrower or dopedlighter. If a structure is given, this small barrier canalso be reduced by increasing the gate voltage. After chargeshaving been transferred into CCDs, the bulk and interface trapsbecome affecting. The devices will be benefited if the bulktrap has fewer trap density, longer trap lifetime,and withelectron traps closer to conduction band. As to interfacetraps, although the n-type acceptor-like traps at interfaceis good for transfer, they also cause more serious charge loss.