本論文以金屬-氧化層-半導體 (Metal-Oxide-Semiconductor ) 場效電晶體為雛型，佐以鍺量子點於閘介電層之中來製備近紅外光光電晶體。主要閘堆疊層結構包含有100 nm 大小的鍺量子點作為光吸收層，以及選用複晶矽閘極以利後續高溫與潔淨度製程整合。利用氧化複晶矽鍺柱來形成鍺量子點，並將其埋藏在介電層中以製備光電晶體。在鍺量子點下方同時會形成有一層厚度約 4.4 nm 的矽氧化層，亦可當作浮點記憶體之穿隧氧化層，之後再藉由控制鍺量子點上方之氧化層，可製備成鍺量子點浮點記憶體。 藉由光電特性量測，可得知鍺量子點光電晶體分別在 850 nm 、980 nm 波長光源(功率分別為146 μW、102 μW) 照射下，通道關閉區域的光電流與暗電流比值可達到4.7×10^6 、1.1×10^6倍且響應度 (responsivity) 在 850 nm 、980 nm 波長光源照射下最高分別可達到 4.1、1.5 A/W。在近紅外光有極高的光暗電流比與響應度。 鍺量子點浮點記憶體在寫入/抹除偏壓分別為 8 V 及 -5 V、操作時間分別約為 60 ms 以及 30 ms 的條件下，可使得元件產生有 0.5 V 的記憶窗口。在儲存能力方面，經過10^5 秒的寫入之後，儲存的電荷量尚保存原本的 32%。在耐用性方面，元件的寫入/抹除操作次數可達到 10^5次以上，仍未見明顯的衰退。本論文呈現之鍺量子點光電晶體及浮點記憶體的製程與現今之互補式金氧半電晶體技術相容，有利於日後的實際整合與應用。 ;A near infrared phototransistor is manufactured with the prototype of Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET) and germanium quantum dots (Ge QDs) in this thesis. The light absorption layer is made by 100 nm Ge QDs, and the gate electrode is made by poly-silicon to consider sequent high-temperature processes and clean integration. Ge QDs are formed by selective oxidation of SiGe pillars and buried in dielectric layer. In the meantime, there is a 4.4 nm SiO2 below the Ge QD which can be applied as a tunneling oxide of floating-dot transistor. Then, Ge QDs flash memory can be achieved by controlling the oxide on the top of Ge QDs. Under 146 uW/102 μW illumination at 850 nm/980 nm, the photo-current-to-dark current ratio and responsivity of Ge QDs phototransistors is 4.7×106/1.1×106 tines and 4.1/1.5 A/W, respectively. The Ge QDs phototransistors exhibit high photo-current-to-dark current and responsivity at near-infrared region. Under the conditions of write/read voltage at 8 V/-5 V and program/erase time of 60 ms/ 30 ms, the Ge QDs floating dots memory devices exhibit the memory window of 0.5 V. The charge retention properties of Ge QDs flash memory devices are 32% after 10¬5 seconds. Moreover, there do not have noticeable degradations of the Ge QDs flash memory devices after the read/write operations up to 105. In this thesis, we demonstrate the process of Ge QDs phototransistors and floating-dots memory devices which can be compatible with prevailing Si CMOS technologies.
