單電子電晶體發展至今，各個研究團隊利用半導體材料製作量子點，雖然目前已經有許多製作量子點的技術陸續被研發出來，但大多都面臨了再現性低與量子點大小位置無法掌控的問題。本論文研究討論利用選擇性氧化複晶矽鍺以形成鍺量子點的技術，除了可利用鍺材料的電子費米波長較矽材料的費米波長大，來克服矽量子點微縮的問題；也可利用矽鍺合金的選擇性氧化克服了量子點需要精準的微影蝕刻技術，且也不需要在高成本的絕緣層上覆矽基板製作等的問題。而本論文實驗調變各種多邊形圖案之孔洞大小，精確地控制鍺量子點之數量與位置。利用多邊形側壁為二氧化矽的條件，且各圖案的內心圓半徑等於或小於15 nm時，可觀察到單一顆的鍺量子點分佈在多邊形圖案中間。而多邊形側壁為氮化矽的條件時，當各圖案的內心圓半徑等於或小於15 nm，也會觀察到單一顆的鍺量子點分佈在多邊形圖案的中間；但當內心圓半徑介於30 nm與70 nm之範圍內，鍺量子點會分佈在多邊形圖案的邊緣甚至是角落。於是我們可利用此方法，對鍺量子點定位與定量。單一顆鍺量子點可供單電子電晶體應用；而兩顆、三顆等等的量子點做為偶合量子點之用。 Recently semiconductor quantum dots have been extensively researched, but the most of the forming quantum dots techniques face the problems of low reproducibility and poor controllability on the position and the number of quantum dots. This thesis demonstrates the feasibility of positioning and numbering Ge quantum dots by means of oxidizing SiGe polygonal cavities with SiO2 and Si3N4 spacers. For polygons with SiO2 spacers have an inner circle radius less than 15 nm, one Ge quantum dot is formed in the center of cavity with a dot size of 10.4 nm. In contrast, polygons with Si3N4 spacers have the same inner circle radius, one Ge quantum dot formed in the center of triangle, square, and pentagonal cavities, with a dot size of 10.4 nm, 12.6 nm, and 10.9 nm. For a triangle with Si3N4 spacers have the inner circle radius between 35 and 40 nm, Ge quantum dots exist only at the corners of triangle, with an average dot size between 9.8 ± 0.7 nm and 10.2 ± 0.6 nm. Using this method, it is reasonable to expect that effective single-electron transistors and coupled quantum dots devices could be realized.
