以矽晶圓為基礎的長波長紅外線偵測器(新型SiGeC 材料之研究)

Abstract

在研究Si/Si1-x-yGexCy/Si quantum well 對熱的穩定性,我們使用x 光繞射 儀去量定晶格常數,加上紅外線分析儀 測量SiC 沉積,最後再用CrO3 加HF 溶 液做蝕刻,它可以使晶格缺陷顯現出來, 由此可知Si/Si1-x-yGexCy/Si quantum well 是否鬆弛,在不同溫度下退火.會發 生數種不同的晶格應力轉變,我們比較 Si1-x-yGexCy 和Si1-xGex 的晶格結構,在 800℃ 兩個小時退火時,它們擁有一樣 的穩定性,直到900 ℃ 兩個小時退 火,Si1-x-yGexCy和Si1-xGex 的晶格結構都 開始產生了鬆弛,而我們測量結果發現, 總結可以說C 加強了Ge 在Si1-xGex 中 的擴散速率,在繼續昇高溫度到950℃ 和1000℃兩小時的退火,Si1-xGex 和Si1- x-yGexCy 晶格結構繼續發生鬆弛,但是 Si1-x-yGexCy 的厚度小於臨界厚度,理論 上不應該產生鬆弛,它的晶格鬆弛可能 由於SiC 的沉積出來造成。

The thermal stability of Si/Si1-xy GexCy/Si quantum wells was studied by high resolution x-ray diffraction(Fig.1, 2, 3), Fourier transform infrared spectroscopy, and defect ecthing. There are different pathways of strain relaxation in this mater system, depending on the annealing temperature. The lattice structure of Si1-x-yGexCy was as stable as the Si1-xGex alloys at the annealing temperature of 800℃ for 2hr. At the annealing temperature of 900℃ for 2hr, the structures of both Si1-x-yGexCy and Si1-xGex started to relax. The addition of C enhanced the Ge outdiffusion in Si1-xy GexCy, as compared to Si1-xGex. The Ge also outdiffused relatively fast compared to C in Si1-x-yGexCy alloys(Fig 4). For the annealing temperature of 950 ℃ and 1000℃ for 2hr, the Si1-xGex and Si1-xy GexCy continued to relaxed with the decrease of strain in the quantum wells, but the thickness of Si1-x-yGexCy was below the critical thickness. The abnormal forrnation of misfit dislocation is probably caused by the SiC precipitate.