閘極介電質氧化鉿與氮氧矽鉿之可靠度研究

Abstract

在這篇論文裡,我們展示HfO2 和 HfSiON 介電質的PBTI退化特性,氧化層中生成的捕捉電荷主導了Hf-base 介電質得PBTI特性,另外,再PBTI stress中,較少的臨界電壓飄移與氧化層捕捉電荷的生成證實了HfSiON相較於HfO2有較好的特性.另一方面,我們也討論了電子的 trapping/de-trapping 效應,與HfO2介電質相比,由於消除了較深層的介電質缺陷HfSiON有較淺的捕捉能階,而在不同溫度下的表現,HfO2介電質與HfSiON介電質有相當程度的不同.HfO2與HfSiON P型場效電晶體在動態的NBTI stress也再論文中一併討論,我們提出在NBTI stress與passivated stress下,電洞捕捉模型.同時,我們由臨界電壓的改變與charge pumping current的特性得知,因為stress所造成的表面狀態在鈍化的過程中將不會有回復的現象.

In this thesis, PBTI degradation for HfO2 and HfSiON NMOSFETs has been demonstrated. The generated oxide trap dominated the PBTI characteristics for Hf-based gate dielectrics. In addition, the reduction of VTH shift and oxide trap generation under PBTI stress indicates that the HfSiON is better than HfO2. On the other hand, the electron trapping/de-trapping effect has been investigated. As compared to HfO2 dielectrics, the HfSiON has shallower charge trapping level due to elimination of deep dielectric vacancies, and the temperature effects are quite different between the HfSiON and HfO2 gate dielectrics. DNBTI stress on HfO2 and HfSiON PMOSFETs has been investigated. The DNBTI model of hole trapping under NBTI stress and the electrons trapping under passivated stress have been proposed. In addition, the characteristics of the VTH shift and charge pumping current under DNBTI stress indicate that the interface states are not recovered during the passivated period.