本論文研究討論利用選擇性氧化複晶矽鍺形成鍺量子點的技術。以及調變奈米溝渠 的幾何結構，有效地控制鍺量子點顆數與位置。鍺量子點形成的位置與複晶矽鍺的氧化截止點有強烈的相關性，利用不同的奈米溝渠側壁(二氧化矽材料或氮化矽)材料與溝渠的大小，可以有效地控制鍺量子點形成的位置。當奈米溝渠側壁為二氧化矽且寬度在30nm 以下時，可觀察到單一顆球形的單晶鍺量子點分布在奈米溝渠的中間，量子點大小為12.5±2.8 nm。在寬度同樣為小於30 nm，而奈米溝渠側壁為氮化矽的條件下，鍺量子點的分布則是隨機的，有的分布在奈米溝渠的中間，有的則在奈米溝渠的邊緣，量子點大小為9.7±1.5 nm。當奈米溝渠寬度為50 nm 或70 nm 時，不論是側壁為氮化矽還是二氧化矽，這兩個條件的鍺量子點皆分布在奈米溝渠的兩側邊緣，其鍺量子點大小分別為11.4±0.9 nm 與8.3±1.4 nm。利用此方法，我們可以氧化奈米溝渠中的複晶矽鍺，形成單一顆鍺量子點供單電子電晶體應用；或兩顆鄰近的量子點做為偶合量子點之用。 This thesis demonstrates that controlling the position and the number of Ge quantum dots (QDs) embedded in SiO2 or Si3N4 tunnel barriers in a self-organized manner is realized by oxidizing SiGe nano-trenches. A single Ge QD in the core or double QDs at the edges of oxidized SiGe trenches could be effectively modulated by the trench geometry and the materials adopted for spacer and bottom layers. For SiGe trenches with SiO2 spacers having an trench width of less than 30 nm, Ge QDs line up in the center of oxidized trenches with an average dot size of 12.5 ± 2.8 nm. In contrast, for SiGe trenches with Si3N4 spacers having the same trench width, smaller Ge QDs (9.7 ±?1.5 nm) reside randomly either in the center or near the edges of oxidized trenches. For SiGe trenches with width of 50 or 70 nm, we observed remarkable twin Ge QDs precipitation closely along each boundary between the trench and the nearby SiO2 and Si3N4 spacers, respectively, with an average dot size of 11.4 ± ?0.9 nm and 8.3 ±?1.4 nm. Using this method, it is reasonable to expect that effective single-electron transistors and coupled QD devices could be realized.
