短P型通道金氧半場效電晶體的可靠性分析

Abstract

本文在對短P型通道金氧半場效電晶體的元件特性退化做量化分析前 ，我們必需先做參數粹取。我們利用高級半導體元件研究實驗室過去發展 的電荷幫浦法來分析介面陷阱和氧化層陷阱的分佈，並且其結果用來解釋 一般電流－電壓特性。我們著重在分析埋層P型通道金氧半場效電晶體的 可靠性。當我們用電荷幫浦法去量未退化元件時，發現與n型通道金氧半 場效電晶體大大不同的奇特現象。因此，表層P型通道金氧半場效電晶體 於是被拿來做比較。我們發現這樣一個現象只有出現在埋層P型通道金氧 半場效電晶體。主動區陷阱的存在是由逆離子通道佈植所產生，並作為解 釋我們所量到介面陷阱分佈的主因。在長時間的直流應力下，主動區陷阱 在介面陷阱分佈量測上呈現較不重要的效應。因此，所量得的分佈結果可 以被用來解釋一般電流電壓特性，包括次臨界電流、導通電流、基板電流 。以這些分析為基礎，我們可以改進元件的設計來達到高效率和高可靠度 的應用。而且，由電荷幫浦法量得的主動區陷阱亦可以幫我們做製程改善 。 In this thesis , the parameter extraction of P-MOSFETs is made first before quantitatively analyzing on the degradation of short-channel P-MOSFETs. The charge-pumping method developed by Advanced Semiconductor Device Reasearch Laboratory has been used to profiling the distributions of the interface-state density and the oxide traps and the results are taken to explain the I-V characteristics. We concentrate our analysis on the reliability of buried-channel P-MOSFETs. When the fresh devices are measured by the charge-pumping method , some strange phenomenon has been discovered and is dramatically different from N-MOSFET*s. The surface-channel P-MOSFETs thus are measured for comparisons. We find that such a phenomenon only appears on counter-implanted buried-channel P-MOSFETs. The existence of the active-region defects due to counter-implant is the major reason to account for the distribution of interface-state density we measured. After stressing for a long time , the active-region defects appear the minor effects on the profiling of the interface-state density. Therefore , the results can be used to explain the I-V characteristics including the subthreshold characteristics , turn-on current and substrate current. Based on these analyses , we can improve the device design for high performance and reliability applications. In addition , the active-region defects measured by the charge-pumping method can also help us for the process improvement.