應變在矽鍺矽異質結構和奈米圖案之研究

Strain on SiGe/Si Heterostructure and Patterned Nanostructures

黃武平(Wu-Ping Huang)

指導教授 ： 鄭鴻祥

國立臺灣大學/電機資訊學院/電子工程學研究所/博士(2008年)

https://doi.org/10.6342/NTU.2008.00029

摘要

本論文主要探討兩種矽鍺/矽異質接面半導體結構應變鬆弛的現象，一個是常見矽鍺虛擬基板，另一個是利用應變鬆弛來製作奈米皺紋型圖案的結構。
矽鍺虛擬基板是利用晶格不匹配來提供應變給覆蓋在其上面的薄膜，因此應變鬆弛後之虛擬基板的品質好壞，直接影響到覆蓋在上方的元件。而在元件應用上，常會使用P型雜質（硼）和N型雜質（銻）來提高半導體的導電率，而矽層的雜質摻雜對矽鍺虛擬基板應變鬆弛的程度以及薄膜晶格的影響是文中探討的重點。實驗結果顯示，不論是摻雜P型還是N型的雜質都會增加虛擬基板應變鬆弛的程度，這主要是由於雜質原子的大小影響晶格所造成的。而隨著雜質摻雜越高，應變釋放的程度越多。
同時，我們探討虛擬基板表面的格子狀圖案，這些固定會產生一些格子狀的圖案是伴隨著格子狀的應變分佈，這主要是來自於界面錯位所產生的，由於在半導體元件製作過程中，不可避免地會經過一些高溫製程。因此我們使用空間拉曼掃瞄來看這些高溫對格子狀圖案的影響。而隨著溫度越來越高到達攝氏一千度一個小時，這些格子狀的應變分佈可以被消除。
最後我們利用應變鬆弛來製作矽鍺材料皺紋型圖案，理論及實驗結果顯示這些皺紋圖案的產生是由彎矩力及拉伸力兩者所造成，此外利用空間拉曼掃瞄看到應變的分佈隨著空間皺紋的高低起伏而變化。

關鍵字

虛擬基板 ； 應變鬆弛 ； 拉曼掃瞄 ； 格子狀圖案 ； 皺紋型圖案

並列摘要

The thesis is focused on the strain relaxation of two kinds of SiGe/Si strucutures: one is the common SiGe virtual substrate, and the other is the strain-induced SiGe wrinkling pattern.
SiGe virtual substrate is widely used to provide strain into overgrown layer caused by lattice mismatch so that the performance of the overgrown layer is strongly affected by the quality of virtual substrate. The use of the impurity doping (B and Sb) is to form a low-resistivity SiGe or Si layer in applications. Therefore, the study is investigated with emphasis on the effect of impurity doping on the degree of strain relaxation and the film quality of SiGe virtual substrate. The results show that with increasing doping concentration, for both p-type and n-type dopants, the degree of strain relaxation increases due to the lattice contraction or expansion.
Crosshatch pattern accompanied with the spatially-varying strain distribution inherently exists on the surface of relaxed SiGe virtual substrate, which is related to the misfit dislocation at the SiGe/Si interface. Considering the high temperature process in manufacturing, the influence of thermal annealing on the crosshatch pattern is investigated. The results show that with the increase of annealing temperature, the density of dislocation increases the smearing out of the strain fluctuation, resulting in a uniform distribution.
Finally, strain-induced wrinkling pattern is discussed. From theoretical and experimental analysis, the formation of wrinkling pattern is a trade-off between bending and stretching energy. In addition, the spatial height variation of wrinkling pattern is followed by a strain distribution.

並列關鍵字

virtual substrate ； strain relaxation ； Raman mapping ； crosshatch pattern ； wrinkling pattern

參考文獻

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