摘要
奈米科學近來引起學術界和工業界的高度興趣和關注。因此，奈米科學的研究正快速發展中。在半導體領域裡，更是朝向“奈米尺度”發展，而研究上，樣品的物理尺寸已經從三維塊材發展到： 二維量子井（異質結構）、一維量子線、零維量子點。因為結構上物理維度的減少，產生不同的能量分佈，改變了元件的性能。 本論文探討了三種以矽為基材的奈米結構之電性傳輸。包括了双位能障異質結構（DBH）、delta摻雜的異質結構、絕緣層上極薄矽之場效應電晶體（ETSOI FET），我們針對上述不同的元件，個別應用了不同的理論方法去建立模型，包含量子傳輸和多通道傳輸矩陣理論。 由模擬來分析比較RTD成長在全鬆弛和部分鬆弛的SiGe緩衝層，結果顯示出室溫下的峰值到谷比（PVR），可通過使用部分鬆弛的SiGe緩衝層的方法來實現。 另一種p-i-p的異質結構，是將硼(Boron) 摻雜在一層本質矽之間，我們對此結構的穿隧效應與双穩態”電壓-電流”特性， 分別描述了實驗測量數據和理論模擬分析。由分析上顯示出双穩態”電壓-電流”特性是由電荷累積所導致的。 我們亦使用了多通道傳輸矩陣理論來分析ETSOI-FET在扭場下的穿透係數和傳輸電流，我們發現由閘極和汲極偏壓造成的扭場將使得彈道傳輸變成非彈道傳輸。
關鍵字
共振穿隧二極體(RTD) ； 雙位能障異質結構（DBH) ； 峰值到谷比（PVR) ； delta摻雜 ； 絕緣層上極薄矽之場效應電晶體（ETSOI FET) ； 量子傳輸 ； 多通道傳輸矩陣並列摘要
Nanoscience has attracted great attention from both academia and industry. Consequently, research on “nanoscience” has advanced rapidly. In the move toward “nano-scale semiconductor”, the physical dimensions of the structures under investigation have moved from 3D bulk material, to 2D films (heterostructure), then 1D quantum wire, and 0D quantum dot. The reduction in the physical dimensions of the structure gives rise to different energy profile that modifies the performances of the devices. This thesis investigate the electrical transport of three types of Si-based nanostructures: (a) n-type resonant tunneling diodes (RTD) with double barrier heterostructure, (b) p-i-p structure with delta-doped at the i-layer, and (c) silicon on insulator field-effect transistor (ETSOI-FET). Different theoretical models are employed to analyze the electrical characteristics depending on the structure of the devices, including conventional quantum transport, multi-channel transfer-matrix. On the RTD, analysis is performed on structure deposited on fully and partially relaxed buffer layer. We show that room temperature peak to valley ratio can be achieved by using partially relaxed SiGe buffer layers. For the p-i-p structure with boron delta-doped in the i-layer, we report both experimental measurement and theoretical analysis of the electrical tunneling. The characteristic of bistability is found. From the analysis, it shows that the charge accumulation at the delta-doped in the i-layer dominated the observation. We have also proposed a theoretical analysis on the transmission coefficients and the transport currents in the ETSOI-FET under the distorted fields formed by gate bias and drain bias which makes ballistic transport non-ballistic.
參考文獻
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