具有氮化矽覆蓋層之形變N型金氧半場效電晶體之性能及可靠度

Abstract

在本論文中，我們主要探討在N型金氧半場效電晶體中，利用電漿化學氣相沈積系統(PECVD)沈積不同厚度的氮化矽覆蓋層來分別對元件通道產生應力時，元件的各項特性。我們發現較厚的氮化矽覆蓋層可以對在下方的元件通道產生較高的舒張應力，並且造成了更高的元件載子遷移率。因此，沈積較厚的氮化矽覆蓋層的元件會擁有較好的元件性能。然而，提高的元件載子遷移率和氮化矽沈積過程會使得元件的熱載子退化效應變得嚴重，而隨著沈積氮化矽覆蓋層的厚度越厚，熱載子退化效應也越嚴重。我們也探討了傅立葉轉換紅外光儀的分析結果。在元件中發現有額外的矽-氫鍵結，代表了電漿化學氣相沈積系統沈積的氮化矽覆蓋層的確含有大量的氫。

In this thesis, we investigated the characteristics of strained-channel NMOSFETs with different thickness of silicon nitride (SiN) capping layer deposited by plasma enhanced chemical vapor deposition (PECVD) system. We found that thicker SiN capping would result in higher tensile stress in the underlying channel and leading to a higher mobility. Therefore, higher performance enhancement was observed for devices with thicker SiN capping. However, the increased mobility and the SiN deposition process would aggravate the hot carrier reliability, resulting in the severest hot carrier degradation for the samples with the thickest SiN capping. The analysis of Fourier transform infrared spectrometer (FTIR) was also investigated. The extra Si-H bonds were observed, indicating that PECVD SiN indeed has abundant hydrogen species.