臺灣博碩士論文加值系統

本論文使用選擇性熱氧化複晶矽鍺柱形成高品質之單晶鍺量子點，並將鍺量子點作為有效的光吸收層，成功製備出不同本質層厚度的P-I (鍺量子點) -N近紅外線光偵測器。藉由不同大小之鍺量子點陣列整合於複晶矽/鍺量子點/單晶矽異質接面之 P-I-N光偵測器二極體架構中，我們在近紅外光的波段下可觀察到光響應。在850 nm、980 nm、 1310 nm 及 1570 nm之雷射光源於2.5 mW的照射下，元件得到的光電流與暗電流比值最高為28、15、2.3以及1.6倍。在近紅外光線照射下，鍺量子點/矽界面所侷限之正電荷造成內建電場的產生，使得元件在操作速度上最快可達到440 MHz之操作頻率。
本文另一主題是以UHV-CVD沉積約1 μm厚堆疊式偶合矽/鍺量子點堆疊結構，來製備近紅外線光偵測器。評估在單一偶合量子點中，增加矽/鍺量子點接面數目的設計，對於光響應之影響。於850 nm、980 nm、1310 nm 及1570 nm 的雷射光源於照射下，其元件所展現之光電流與暗電流比值最高為4000 (0.45 mW)、2200 (0.45 mW)、52 (9.4 mW) 與 4.2 (5.4 mW) 倍。隨著單位元下矽/鍺量子點異質接面的數目增加，可清楚地觀察到元件之開路電壓會隨接面數目增加而變大，因此證明了矽/鍺接面數目越多，內建電場也隨之增強，有利於光響應的增進。

This thesis produced high-quality and single-crystal Ge quantum dots (QDs) using selectively oxidation of SiGe pillars, and demonstrated Ge-QD P-I-N near-infrared photodetectors with various sizes of Ge QD. The P-I-N photodetectors exhibit various near-infrared photoresponsivities by tuning different sizes of Ge-QD arrays integrated in the photodetectors. Under 2.5 mW illumination at 850, 980, 1310, and 1570 nm, the photodetectors exhibit the photo-current-to-dark-current ratio as high as 28, 15, 2.3, and 1.6, respectively. Under near-infrared illumination, the positive holes confined in the valance band offset between Ge QD and the Si substrate, establishing a built-in electric field (E-field), leading the transient response of the photodetectors as high as 440 MHz.
The other topic of this thesis focused the formation of near-infrared photodetectors with a 1-μm-thick Ge QD/Si heterojunction contained various number of Ge QD/Si stacks by using Ultra-High Vacuum Chemical Vapor Deposition (UHV-CVD), and investigated the photoresponsivity of the photodetectors affected by the number of Ge QD/Si stacks. The photo-current-to-dark-current ratio of the photodetectors is 4000 (0.45 mW), 2200 (0.45 mW), 52 (9.4 mW), and 4.2 (5.4 mW) under illumination at 850, 980, 1310, and 1570 nm, respectively. The open-circuit voltage increases with the number of heterojunction of Ge QD/Si, which indicates the increasing built-in E-field improves the photoresponsivity.

第一章 研究動機 1
1-1簡介 1
1-2鍺在光電元件上的應用 2
1-3矽鍺整合時所存在的問題 2
1-4研究動機 3
1-5論文概要 5
第二章 鍺/矽異質接面之成長及光偵測器之元件物理 9
2-1前言 9
2-2 光二極體及PIN光偵測器之操作原理 9
2-2-1光二極體 9
2-2-2 P-I-N光偵器 10
2-3光偵測器之重要參數 10
2-3-1光響應度 (Responsivity) 10
2-3-2截止波長 (Cut off Wavelength) 11
2-3-3量子效率 (Quantum efficiency) 11
2-4控制鍺量子點大小以調控本質層厚度 11
2-5藉由不同鍺量子點堆疊結構以調變能帶結構與鍺含量 11
第三章 P-I-N光偵測二極體製備及電性量測分析 16
3-1前言 16
3-2 P-I-N光偵測器的完整製作與關鍵製程 16
3-2-1關鍵製程-本質層厚度之調控 16
3-2-2關鍵製程-回蝕刻裸露量子點 16
3-2-3 P-I-N光偵測器完整製作流程 18
3-3 P-I-N光偵測器光電特性量測分析 21
3-3-1 P-I-N光偵測器之功率相依特性 21
3-3-2 P-I-N光偵測器之波長相依特性 23
3-3-3 P-I-N 光偵測器之溫度相依特性 24
3-3-4 P-I-N 光偵測器之操作速度 24
第四章 調變能帶結構與鍺含量以應用於光偵測元件製作與電性分析 39
4-1前言 39
4-2調變能帶結構與鍺含量應用於光偵測器完整製作流程 39
4-3調變能帶結構與鍺含量應用於光偵測器光電特性量測分析 40
4-3-1調變能帶結構與鍺含量應用於光偵測器之暗電流特性 40
4-3-2調變能帶結構與鍺含量應用於光偵測器之功率相依特性 41
4-3-3調變能帶結構與鍺含量應用於光偵測器之波長相依特性 42
4-3-4調變能帶結構與鍺含量應用於光偵測器之溫度相依特性 43
第五章 結論與未來展望 50
參考文獻 51

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