本論文係利用製作不同大小的奈米溝渠(寬度、長度)與側壁材料，以求達到有效地控制鍺量子點形成的位置、量子點形成顆數與穿隧介電層厚度之目的。當矽鍺奈米溝渠寬度為40 nm以下完全被氧化後，若側壁為SiO2 spacer時，可觀察到形成一排分佈於奈米溝渠中間的鍺量子點；而若側壁為Si3N4 spacer時，可觀察到形成一排隨機分散於溝渠內的鍺量子點。反之當矽鍺奈米溝渠寬度為50?70 nm時，不論側壁為SiO2或Si3N4，在氧化後皆可觀察到形成兩排分佈於奈米溝渠邊緣的鍺量子點。為了控制量子點的顆數，可以再藉由調變奈米溝渠的長度來有效地控制鍺量子點顆數。當奈米溝渠側壁為氮化矽且寬度在50 nm以下、溝渠長度60 nm以下時，可觀察到在氧化後奈米溝渠中存在有單一顆鍺量子點，此量子點大小約為10 nm。當溝渠長度為110 nm時，可觀察到在氧化後有兩顆鍺量子點分布在奈米溝渠中。溝渠長度為180 nm時，可觀察到在氧化後有三顆鍺量子點分布在奈米溝渠中；溝渠長度為300 nm時，可觀察到在氧化後有四顆鍺量子點分布在奈米溝渠中。而奈米溝渠側壁為氮化矽的條件下，鍺量子點皆分布在奈米溝渠的兩側邊緣。利用此結果我們成功地製作出單一顆鍺量子點與兩顆量子點(耦合量子點)鍺量子點穿隧二極體，並對元件current-voltage ( ID-VD)及differential conductance voltage ( G-V)做電性分析，進一步探討量子點內的量子效應。 The main purpose of this thesis is to control the position and the numbers of Ge quantum dots (QDs) and the thickness of tunneling barrier by way of modulating the width and the length of oxidized SiGe nano-trenches and the materials adopted for spacer layers. For SiGe trenches with SiO2 spacers having an trench width of less than 40 nm, Ge QDs line up in the center of oxidized trenches. In contrast, for SiGe trenches with Si3N4 spacers having the same trench width, Ge QDs reside randomly either in the center or near the edges of oxidized trenches. In order to control the number of Ge QDs, we can further change the length of SiGe nano-trench. For SiGe trenches with Si3N4 spacers having an trench width less than 50 nm and length less than 60 nm, a single Ge QD reside randomly in oxidized trenches with an average dot size of about 10 nm. In contrast, for SiGe trenches with Si3N4 spacers having the same trench width and length of 110 nm, twin Ge QDs reside in oxidized trenches. For SiGe trenches with length of 180 or 300 nm, we observed three and four Ge QDs precipitation nearby Si3N4 spacers, respectively. Using this result, we have fabricated a single and coupled Ge QD tunneling diodes and analyzed their electrical characteristics, we can discuss the quantum confinement effect in detail by way of the measured I-V and differential conductance voltage (G-V) characteristics. It is reasonable to expect that effective single-electron and coupled QD devices could be realized by means of this method.
