奈米應變矽元件載子傳輸模型分析與其可靠度相關性探討

Abstract

嶄新的元件都在near-ballistic的條件下操作。因此,吾人需以載子傳輸理論來修正一般傳統的原件操作模型。雙軸應變與單軸應變p型金氧半元件,在施以相同的熱電子加壓條件下,傳統可靠度量測並沒有指出其劣化情形的差異，但是使用載子傳輸模型的參數分析，吾人將可知道元件詳細的劣化情形。在尚未加壓劣化前，汲極源極矽鍺p型元件有較高的載子入射速度。而矽锗通道元件有較高的ballitic參數，但在加壓劣化後，其ballitic也有較多的退化。另一方面，在熱電子加壓劣化後，不同n型金氧半元件的ballitic參數，呈現上升或下降兩種情形。吾人對此重要位障的變化有所研究並發展一套新方法用以評估之。研究結果顯示，在所選出的兩研究對象，無論ballitic是上升還是下降，此重要位障都變得更加尖銳。本論文開發出一個嶄新的方法評估此重要位障的改變，且為首次將載子傳輸參數應用在元件可靠度問題探討的相關研究。

The modern devices are operated at near-ballistic conditions. Therefore, the conventional model of devices should be corrected by the carriers transport model. The SiGe on S/D pMOS devices called as uniaxial compressive strained-Si devices have higher injection velocity, but they have worse ballistic than others. The SiGe channel pMOS devices also called as biaxial compressive strained-Si devices have higher ballistic than others, but they degrade seriously in ballistic after HC stress. As applying the same hot carrier stress condition, the uniaxial and biaxial strained-Si pMOS devices showed the same degradation with the conventional reliability measurements. However, these two kinds of devices have different variation in transport parameters. After HC stress, the control nMOS devices dropped their ballistic and others increased oppositely. Base on this point of view, we were interested in the critical barrier near by the source side. Thus, this work developed a wholly new method to calculate the variation of this critical barrier. The results showed that the barriers became sharper and independent of the ballistic. This is the first time to investigate the reliability issues with the transport parameters, and a new method for evaluating the variation of critical barrier is deduced.