以分子束磊晶法成長砷化銦奈米線並整合於矽基板之研究

中文摘要　　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。在本論文的第二章節，我們以分子束磊晶技術，在無結構之Si (111) 基板上成長InAs，在特定條件下我們發現InAs會以奈米柱的方式呈現。為了要將InAs定位並且微縮尺寸，於是我們利用電子束微影技術搭配蝕刻技術製作以及研究奈米圖案化之Si (111) 基板，並且利用此圖案化基板成長InAs，以控制InAs奈米結構的位址以及尺寸，成長於此圖案化基板之奈米線其成長方向不管垂直與否幾乎都為{111} (<111>有四個等效的方向) 。本論文也成功製作了垂直式InAs奈米線兩端點元件於Si(111)基板上，並且從InAs奈米線陣列的I-V特性求出InAs的電子遷移率為2530 cm2/V-s。在本論文的第三章節，我們利用聚焦He+束直寫技術製作奈米圖案化之Si (111) 基板，成功製作出直徑八奈米的圓孔陣列圖案化基板，並從此圖案化基板成長出InAs奈米線研究並觀察其晶格結構以及缺陷。我們發現較低的氦離子劑量能夠促進(111) B InAs在高度不匹配Si上的成核，進一步提高InAs奈米線的垂直成長率; 相反地，我們發現較高的氦離子劑量，會造成Si表面嚴重損傷，導致傾斜和條狀奈米線的產生，除了由(111) A域成長出的InAs奈米線以外，我們還觀察到由於缺陷所以起的孿晶並導致的新的奈米線成長方向。在論文最後我們利用聚焦氦離子束技術可以在Si基板中形成單個奈米孔洞，並可以精確被定位在基板中。奈米孔洞的位置可以通過聚焦氦離子束系統的直接寫入來精確定位，而孔洞的深度和大小可以分別由氦離子的加速電壓和劑量決定並且經過氦離子製程的樣品在Si中會形成橢球形非晶區，此非晶區是由氦-空缺複合物和氦氣泡缺陷所組成，並經過熱處理後在該區域的中心形成孔洞。經過適當的熱處理條件後，在825 ℃退火的樣品，我們利用HAADF、EDS以及cross-sectional SEM影像觀察到表面由{111}面所構成可定位的單個奈米級孔洞。

關鍵字

砷化銦奈米線；分子束磊晶；圖案化基板；選區成長；聚焦氦離子束；奈米孔洞

並列摘要

Abstract InAs is a material which is widely used in many different fields, including many electronic and optoelectronic devices. In the second chapter of this paper, we use molecular beam epitaxy technology to grow InAs on an unstructured Si(111) substrate. Under suitable growth conditions, we find that InAs represented as micro rods.Electron beam lithography and dry etching techniques are used to fabricate nano-patterned Si(111) substrates. InAs nanowires were successfully grown on the patterned substrate and the position and size of the InAs nanowires were precisely controlled. The direction of growth of the nanowire is almost {111} regardless it is vertical or not (There are four equivalent directions in <111>). In our work, the two terminals devices with vertical InAs nanowire arrays are successfully fabricated. The electron mobility of InAs nanowire is extracted as 2530 cm2/V-s. In the third chapter of this paper, we used the helium ion beam technology to fabricate a patterned Si (111) substrate, and successfully fabricated a hole array with extremely small diameter ~8 nm. We also grew InAs nanowire from the patterned substrate. We found that low He+-ion dosage is able to facilitate the nucleation of (111) B InAs on the highly mismatched Si, leading to the vertical growth of InAs nanowires (NWs) . However, high He-ion dosage enhances the growth of non-vertical NWs. In addition to tilted NWs grown from (111) A domain, we found a new type due to twinning of Si(-1-1 1) plane with respect to (-1-1-1) plane. At the end of the dissertation, we have demonstrated the formation of a nanoscale void embedded in SiO2/Si using He-ion beam technique. The position of the void on the substrate can be controlled by the He-ion direct writing. The depth and size of the void can be controlled by the acceleration voltage and dosage of the He-ions. The injected He-ions firstly formed an amorphous region which is ellipsoidal shape. The depth of the region is in consistent with the range of He-ion obtained from SRIM/TRIM simulation. Thermal annealing aggregates the He-vacancy complexes and He bubbles resulting from the injection and starts the recrystallization from the boundary. In this manner, a void is formed in the central of the region. Through HAADF imaging, EDS scanning, and SEM imaging, the formation of the void is confirmed. For thermal treatments at 825 ℃, we observed a void formed by {111} facets.