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  • 學位論文

以分子束磊晶法成長砷化銦奈米線及其材料特性研究

Study on the InAs nanowire characteristics grown by a molecular beam epitaxy system

指導教授 : 林浩雄

摘要


InAs是一個可以廣泛應用於許多不同領域的材料,包含了許多電子與光電元件。在本論文的第一個部分,我們以分子束磊晶技術,在具有奈米溝渠圖案的 (001)Si基板上成長了InAs的奈米線。由於InAs奈米線成長於(001)晶向的基板天生會朝向四個等效的<111>方向成長;因此在這個部分,我們針對奈米線的成長方向做了長晶手法上的控制,我們發展出一個叫做二階段成長的方法:先固定基板成長一段時間,目的是為了使InAs只成核於溝渠的一個端點,再旋轉基板成長,如此可以控制InAs奈米線超過90%以上皆往同一個 [111]方向成長;接著我們分析了穿透式電子顯微鏡得到的結果,發現在極小的V/III條件下,InAs奈米線極容易由溝渠端點的(111)Si的殘餘區塊長出;而在溝渠中央部分沒有(111)Si殘餘區塊,其V/III較高的位置則傾向長成島狀與團簇結構。   接著,在本論文的第二部分,我們同樣以分子束磊晶技術,成長了InAs塊材。我們研究了當InAs經過聚焦式離子束技術成像過後,對於晶格品質所遭受到的破壞程度。我們使用拉曼量測技術,比較了有無經過聚焦式離子束技術成像的InAs之拉曼頻譜,發現經過聚焦式離子束技術成像的InAs拉曼頻譜在~230 cm-1的位置會多出一個較寬的訊號,我們以空間關聯模型擬合了這個訊號,確認這個訊號式來自於InAs晶格遭受到破壞之後所出現的訊號。我們同時觀察到,即便是在成像離子注量極低的情況下(離子注量為7.4 × 1010 cm−2),InAs所受到的破壞程度都非常大,更進一步的是,隨著離子注量以數量級的程度大幅上升,InAs晶格所受到的破壞程度卻沒有大幅度的增加。我們認為InAs即使在離子注量極低的情況下仍遭受到很大的破壞,其原因為聚焦式離子束技術之非常大的電流密度與極慢的掃描速率所導致;而當離子注量大幅度增加,破壞程度卻沒什麼變化的原因,這是因為:當離子注量升高時,由於InAs的熱導係數較低,會造成局部溫度上升,此溫度消除了因為離子注入所產生的缺陷。

並列摘要


InAs is a promising material since it can apply in many electronic or optoelectronic devices. In the first part of this thesis, we had grown InAs nanowire on the nanotrench-patterned (001) Si substrate by using molecular beam epitaxy. Naturally, InAs nanowire grown on (001)-oriented substrate would grow into four equivalent <111> directions. Thus, in this part, we developed a two-step growth method in order to control InAs growth direction. We first grown InAs without substrate rotation in order to seed InAs nucleus at the only one end of trench, then the growth proceeded with substrate rotation. The result of the sample grown by this two-step growth method reveal over 90% InAs nanowire with single [111] growth direction. Transmission electron microscope and one dimensional Fourier image analyses show that InAs NW can be easily grown from the (111) Si residue due to the tiny residue volume and low V/III ratio. In contrast, InAs nucleus, located at the center of the trench, developed into island and cluster because of the high V/III ratio and large lattice mismatch. In the second part of this thesis, we studied the effect of focused ion beam imaging on the crystallinity of InAs by using Raman scattering measurement. We found that the Raman spectrum for the imaged sample would show an additional broad band signal at ~230 cm-1. Spatial correlation model was used to fit this signal and confirmed that this signal was induced by FIB imaging. We found that the crystallinity of InAs suffer a severe damage even under the noisiest imaging condition (7.4 × 1010 cm−2). However, the InAs damage showed a fluence-independent behavior whit increasing ion fluence. We attribute the severe damage to the high beam current density and the low scanning speed of the FIB imaging process. These process conditions along with the low InAs thermal conductivity also lead to a high local temperature in the exposed region, which largely annihilated the defects and results in the nearly fluence independent behavior.

參考文獻


[3.8] 蔡松澔, “聚焦離子束系統輔助砷化銦奈米線歐姆接觸與金氧半 場效應電晶體製作,” 國立台灣大學電機資訊院子工程學研究所 碩士論文, Ch. 4, pp. 26-37, 2015.
[1.1] Wayne H. Lau and Michael E. Flatté, “Effect of interface structure on the optical properties of InAs/GaSb laser active regions,” Appl. Phys. Lett., vol. 80, pp. 1683-1685, 2002.
[1.2] W. W. Bewley, E. H. Aifer, C. L. Felix, I. Vurgaftman, and J. R. Meyer, “High-temperature type-II superlattice diode laser at λ=2.9 mm,” Appl. Phys. Lett., vol. 71, pp. 3607-3609, 1997.
[1.3] Y. Wei, J. Bae, A. Gin, A. Hood, M. Razeghi, Gail J. Brown, M. Tidrow, “High quality type II InAs/GaSb superlattices with cutoff wavelength ~3.7 mm using interface engineering,” J. Appl. Phys., vol. 94, pp. 4720-4722, 2003.
[1.5] W. Dobbelaere, J. De Boeck, C. Bruynseraede, R. Mertens and G. Borghs, “InAsSb light emitting diodes and their applications to infra-red gas sensors,” Electron Lett., vol. 29, pp. 890-891, 1993.

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